| |
| 23 Apr 2008 19:37:20 |
| Charles Carroll |
| Hurrying the recovery - Rushing into the catch |
Dear all - While out on the water yesterday morning I may have stumbled on another rowing metaphor. Taking a good catch is a like painting a house. Most of the work is in the preparation. Isn't this just as true for rowing? Most of the work is in the preparation. To be slightly more specific, it occurs to me that most of the work in sculling may be in the recovery, not the drive. Take Volker Nolte's assertion that ". the stroke rate is produced during the recovery." This means that to raise the rate, thus to go faster, you need to speed up the recovery. But whenever I try to speed up the recovery it has the opposite effect. Instead of going faster I go slower. I end up being jerky and tense and checking the boat. On the other hand, when I don't rush the recovery I tend to go faster because I am smoother and more relaxed. I think anyone who has sculled knows that it can be hard work to be smooth and relaxed in the recovery, especially when you are trying to speed up the recovery. For how do you speed up the recovery without slowing down the shell? What do you do to pick up the pace of the recovery while staying smooth and relaxed? Cordially, Charles |
| 24 Apr 2008 00:28:49 |
| sully |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 23, 7:37=A0pm, "Charles Carroll" <charles_carr...@comcast.net > wrote: > Dear all - > > While out on the water yesterday morning I may have stumbled on another > rowing metaphor. Taking a good catch is a like painting a house. =A0Most o= f > the work is in the preparation. > > Isn't this just as true for rowing? Most of the work is in the preparation= . > > To be slightly more specific, it occurs to me that most of the work in > sculling may be in the recovery, not the drive. Charles These are good questions that might serve to illuminate the ying and yang of rowing. To catch properly does depend on the recovery. You want to eliminate all active movements of your body by the last third of your recovery except for the lift of the hands so that you feel that the blades are being set by your seat. But this is not work, in any sense. All of the work happens in the drive. Often, this work can contribute to slowing the boat more drastically by poor catch technique, but overall moving the boat happens on the drive. |
| 24 Apr 2008 01:12:32 |
| carolinetu |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 24, 8:28=A0am, sully <s...@slac.stanford.edu > wrote: > On Apr 23, 7:37=A0pm, "Charles Carroll" <charles_carr...@comcast.net> > wrote: > > > Dear all - > > > While out on the water yesterday morning I may have stumbled on another > > rowing metaphor. Taking a good catch is a like painting a house. =A0Most= of > > the work is in the preparation. > > > Isn't this just as true for rowing? Most of the work is in the preparati= on. > > > To be slightly more specific, it occurs to me that most of the work in > > sculling may be in the recovery, not the drive. > > Charles > These are good questions that might serve to illuminate the ying and > yang of rowing. > > To catch properly does depend on the recovery. =A0 You want to eliminate > all active movements of your body by the last third of your recovery > except for the lift of the hands so that you feel that the blades are > being set by your seat. > > But this is not work, in any sense. > > All of the work happens in the drive. > > Often, this work can contribute to slowing the boat more drastically > by poor catch technique, but overall moving the boat happens on the > drive. I would interpret Nolte's remark to mean two things: 1. Raise the rate by fast hands at the finish and catch 2. Don't slow the boat down on the recovery - shift your weight onto the feet early and minimise any movement which is likely to upset the balance and trim of the boat. I'd better go and read what Nolte actually wrote, in case I've got it wrong! Caroline |
| 24 Apr 2008 13:19:30 |
| Carl Douglas |
| Re: Hurrying the recovery - Rushing into the catch |
Charles Carroll wrote: > Dear all - > > While out on the water yesterday morning I may have stumbled on another > rowing metaphor. Taking a good catch is a like painting a house. Most > of the work is in the preparation. > > Isn't this just as true for rowing? Most of the work is in the preparation. > > To be slightly more specific, it occurs to me that most of the work in > sculling may be in the recovery, not the drive. > > Take Volker Nolte's assertion that ". the stroke rate is produced during > the recovery." This means that to raise the rate, thus to go faster, > you need to speed up the recovery. But whenever I try to speed up the > recovery it has the opposite effect. Instead of going faster I go > slower. I end up being jerky and tense and checking the boat. On the > other hand, when I don't rush the recovery I tend to go faster because I > am smoother and more relaxed. > > I think anyone who has sculled knows that it can be hard work to be > smooth and relaxed in the recovery, especially when you are trying to > speed up the recovery. For how do you speed up the recovery without > slowing down the shell? What do you do to pick up the pace of the > recovery while staying smooth and relaxed? > Charles - Nolte's right. But whence came the idea that the catch is a painted & decorated edifice? Nor do you necessarily shorten recovery time by faster hands away (which I think is implied in what you wrote) - sometimes rather the opposite. The recovery should be one smooth action, no part exaggerated in comparison to any other part. It leads directly into the catch _without hesitation_. It is a common fault to come forward & then think about the catch. The catch is a moving dynamic thing, not a slow-down, pause, scratch yer bum & stick it in affair. It must be quick, slick & without interruption, or you both check the boat & lose the first part working part of the stroke. When folk find rating hard to get, so often that's because, as you seem to find, what they're doing is jerky. It's jerky because they concentrate on some bits while doing other bits as slowly as ever. If you try to speed recovery by moving the hands away significantly faster, but then slow down to "normal" speed &, worse still, continue to check before the catch, you imposing a string of accelerations & decelerations on your action, all of which waste time, cost effort & spoil flow. The fastest way from A to B is always by a smooth process. The rhythm, & the inter-relationship of speeds at all stages, should be much the same at the higher & the lower speeds. to try to increase speed by forcing just part of the action is bound to screw you up. And now to the catch, which is often where attempts at increased rating fail: So many of us spend idle time at the catch. Partly because someone told us we had to have pressure on the feet to help us compress, & partly because we're told we should slow before the catch. Since the catch has to be fast (but not very fast) it makes no sense to stop & then try to achieve instant acceleration from zero when the inevitable circular action at the catch (NB there is no corresponding circular action at the finish) allows you to sustain hand speed around that turn & into the catch. Only you decide otherwise. Now imagine a time interval of 0.1 second: that's not long, but it is long in terms of a total recovery time of ~1 second at 32spm. Suppose you spend that .1 second hanging at the catch while kidding yourself you're "building" for the catch? Now suppose you cut that time to 0.05 second? Hey presto! your rate's up by almost 1 pip. Or cut out all of that dead spot & your rate will rise by almost 2 pips. And then concentrate less on the hands-away & more on just relaxing & on keeping all of the recovery moving - I'm sure you will nolonger find rating a problem. Put simply, the simpler & smoother all your actions, & the fewer stylistic twiddles you impose on finish, recovery & catch, & the more you put into finishing solid & catching quickly, the easier those higher ratings will be. Cheers - Carl -- Carl Douglas Racing Shells - Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK Find: http://tinyurl.com/2tqujf Email: carl@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682 URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers) |
| 24 Apr 2008 05:20:10 |
| Paul |
| Re: Hurrying the recovery - Rushing into the catch |
On 24 Apr, 03:37, "Charles Carroll" <charles_carr...@comcast.net > wrote: > Dear all - > > While out on the water yesterday morning I may have stumbled on another > rowing metaphor. Taking a good catch is a like painting a house. =A0Most o= f > the work is in the preparation. > > Isn't this just as true for rowing? Most of the work is in the preparation= . > > To be slightly more specific, it occurs to me that most of the work in > sculling may be in the recovery, not the drive. > > Take Volker Nolte's assertion that ". the stroke rate is produced during t= he > recovery." =A0This means that to raise the rate, thus to go faster, you ne= ed > to speed up the recovery. But whenever I try to speed up the recovery it h= as > the opposite effect. Instead of going faster I go slower. I end up being > jerky and tense and checking the boat. On the other hand, when I don't rus= h > the recovery I tend to go faster because I am smoother and more relaxed. > > I think anyone who has sculled knows that it can be hard work to be smooth= > and relaxed in the recovery, especially when you are trying to speed up th= e > recovery. For how do you speed up the recovery without slowing down the > shell? What do you do to pick up the pace of the recovery while staying > smooth and relaxed? > > Cordially, > > Charles An excersise I do to try and work on this is to reverse the ratio of the stroke. No work in the water, no really none at all, and very fast recovery and catch. The only way to do it with no run on the boat to stabilise it is to be very relaxed. You look prety stupid doing it but I think it helps. Paul |
| 24 Apr 2008 05:26:03 |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 24, 1:20=A0pm, Paul <pgosl...@hotmail.co.uk > wrote: > On 24 Apr, 03:37, "Charles Carroll" <charles_carr...@comcast.net> > wrote: > > > > > > > Dear all - > > > While out on the water yesterday morning I may have stumbled on another > > rowing metaphor. Taking a good catch is a like painting a house. =A0Most= of > > the work is in the preparation. > > > Isn't this just as true for rowing? Most of the work is in the preparati= on. > > > To be slightly more specific, it occurs to me that most of the work in > > sculling may be in the recovery, not the drive. > > > Take Volker Nolte's assertion that ". the stroke rate is produced during= the > > recovery." =A0This means that to raise the rate, thus to go faster, you = need > > to speed up the recovery. But whenever I try to speed up the recovery it= has > > the opposite effect. Instead of going faster I go slower. I end up being= > > jerky and tense and checking the boat. On the other hand, when I don't r= ush > > the recovery I tend to go faster because I am smoother and more relaxed.= > > > I think anyone who has sculled knows that it can be hard work to be smoo= th > > and relaxed in the recovery, especially when you are trying to speed up = the > > recovery. For how do you speed up the recovery without slowing down the > > shell? What do you do to pick up the pace of the recovery while staying > > smooth and relaxed? > > > Cordially, > > > Charles > > An excersise I do to try and work on this is to reverse the ratio of > the stroke. No work in the water, no really none at all, and very fast > recovery and catch. The only way to do it with no run on the boat to > stabilise it is to be very relaxed. You look prety stupid doing it but > I think it helps. > > Paul- Hide quoted text - > > - Show quoted text - Our coach is working on this with us, the aim is to place the blade in the water without any pause or hesitation. Harder than it sounds without the slightest hesitation. |
| 24 Apr 2008 05:55:16 |
| donal.casey@gmail.com |
| Re: Hurrying the recovery - Rushing into the catch |
On 24 Apr, 13:26, JBC8...@googlemail.com wrote: > On Apr 24, 1:20=A0pm, Paul <pgosl...@hotmail.co.uk> wrote: > > > > > > > On 24 Apr, 03:37, "Charles Carroll" <charles_carr...@comcast.net> > > wrote: > > > > Dear all - > > > > While out on the water yesterday morning I may have stumbled on anothe= r > > > rowing metaphor. Taking a good catch is a like painting a house. =A0Mo= st of > > > the work is in the preparation. > > > > Isn't this just as true for rowing? Most of the work is in the prepara= tion. > > > > To be slightly more specific, it occurs to me that most of the work in= > > > sculling may be in the recovery, not the drive. > > > > Take Volker Nolte's assertion that ". the stroke rate is produced duri= ng the > > > recovery." =A0This means that to raise the rate, thus to go faster, yo= u need > > > to speed up the recovery. But whenever I try to speed up the recovery = it has > > > the opposite effect. Instead of going faster I go slower. I end up bei= ng > > > jerky and tense and checking the boat. On the other hand, when I don't= rush > > > the recovery I tend to go faster because I am smoother and more relaxe= d. > > > > I think anyone who has sculled knows that it can be hard work to be sm= ooth > > > and relaxed in the recovery, especially when you are trying to speed u= p the > > > recovery. For how do you speed up the recovery without slowing down th= e > > > shell? What do you do to pick up the pace of the recovery while stayin= g > > > smooth and relaxed? > > > > Cordially, > > > > Charles > > > An excersise I do to try and work on this is to reverse the ratio of > > the stroke. No work in the water, no really none at all, and very fast > > recovery and catch. The only way to do it with no run on the boat to > > stabilise it is to be very relaxed. You look prety stupid doing it but > > I think it helps. > > > Paul- Hide quoted text - > > > - Show quoted text - > > Our coach is working on this with us, the aim is to place the blade in > the water without any pause or hesitation. Harder than it sounds > without the slightest hesitation.- Hide quoted text - > > - Show quoted text - If you hold the blades out of the water and tap the blades in and out you will soon see that the speed of the blade of its own volition into the water is plenty fast enough. During the recovery you are holding the blades away from the water. The preparation for the catch should be relaxing sufficiently quickly for the blades to be able to take the catch with pretty much a maximum of their own gravity as controlled by you. Im a firm believer in , the illusion at least, of taking the catch whilst you are still going forward rather than when you have reached the catch. Better to be a bit splashy and onto the next stroke than hanging around to get the blade in................... Donal |
| 24 Apr 2008 06:54:10 |
| alston |
| Re: Hurrying the recovery - Rushing into the catch |
Finally, a topic and discussion worth reading, and keeping. Thanks. |
| 24 Apr 2008 10:06:51 |
| Charles Carroll |
| Re: Hurrying the recovery - Rushing into the catch |
Caroline - The pages you want in "Rowing Faster" are 179-181, the Strictly Science section of Nolte's chapter on the recovery. You'll find the quote on page 181. I think you'll see that these pages provide serious support for what Carl has been saying about the relationship between the recovery, drive, and stroke rate. Gotta run if I am going to get any sculling in this morning. Cordially, Charles |
| 24 Apr 2008 14:36:21 |
| Lauren G |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 24, 5:55 am, "donal.ca...@gmail.com" <donal.ca...@gmail.com > wrote: > > If you hold the blades out of the water and tap the blades in and out > you will soon see that the speed of the blade of its own volition into > the water is plenty fast enough. During the recovery you are holding > the blades away from the water. The preparation for the catch should > be relaxing sufficiently quickly for the blades to be able to take the > catch with pretty much a maximum of their own gravity as controlled by > you. Im a firm believer in , the illusion at least, of taking the > catch whilst you are still going forward rather than when you have > reached the catch. Better to be a bit splashy and onto the next stroke > than hanging around to get the blade in................... > > Donal My coach put it just that way this morning - "feel like you're putting the blade in while still coming forward" He's trying to cure me of shooting the slide - quicker catch=better connection=less shooting the slide? I hope so, something's gotta work! Lauren |
| 24 Apr 2008 18:45:12 |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 24, 2:37 pm, "Charles Carroll" <charles_carr...@comcast.net > wrote: > Dear all - > > While out on the water yesterday morning I may have stumbled on another > rowing metaphor. Taking a good catch is a like painting a house. Most of > the work is in the preparation. > > Isn't this just as true for rowing? Most of the work is in the preparation. > > To be slightly more specific, it occurs to me that most of the work in > sculling may be in the recovery, not the drive. > > Take Volker Nolte's assertion that ". the stroke rate is produced during the > recovery." This means that to raise the rate, thus to go faster, you need > to speed up the recovery. But whenever I try to speed up the recovery it has > the opposite effect. Instead of going faster I go slower. I end up being > jerky and tense and checking the boat. On the other hand, when I don't rush > the recovery I tend to go faster because I am smoother and more relaxed. > > I think anyone who has sculled knows that it can be hard work to be smooth > and relaxed in the recovery, especially when you are trying to speed up the > recovery. For how do you speed up the recovery without slowing down the > shell? What do you do to pick up the pace of the recovery while staying > smooth and relaxed? > > Cordially, > > Charles Carl's got good points as are references to Nolte (Rowing Faster). I get to watch some pretty good catches on a regular basis with 7 olympic qualified boats training outside my office window. That aside. One thing people forget is that even though the oars are out of the water AND the boat is speeding up during the recovery, the SYSTEM (boat, blades, rower - the sum of their centres of mass) can do nothing except slow down when the blades are out of the recovery unless at that moment you went over a waterfall. With intermitent propulsion is intermittent non-propulsion, and once the propulsive phase of the stroke is over, it's just a drag what happens to the boat ;-) One thing you can try at the catch - even before you go out on the water - ask yourself - if the SYSTEM is slowing down, and the BOAT is going faster, how does it do that? Look at the boat carefully, and think about how the boat goes faster and "goes past you" while you're preparing for the next stroke. (here's a hint - it might be where you put your feet). A little experiment - a) move to and from the catch position without the blades going in the water (or with them skimming the surface), and try to pay attention to the movements of the seat - feet. See if you can make the FOOT STRETCHER move with as little hesitation as possible at the point of transition from recovery to drive. When you've managed that, do it again, but watch something floating next to the boat - THE BOAT moves back and forth beside the floating object, YOU sit there, moving forward and backward very little, while your boat moves back and forth. so - when your feet (in answer to the question above) get to that "tucked up position" and are about to push again, you want your sticks to enter the water so that when you start to push (remember, no time at the catch position), that push on the boat (normally causing it to want to go backwards) causes the oarlocks/gates/pins to run into the back of the blade at the wear-plate-collar junction. If the blades are in the water at this point, the boat moves forward relative to the motion, if the blades are in the air at this point, the boat moves aft relative to the motion of the mass centre of the system. So - put the blades in at full reach - not before, not after... AT full reach. and keep moving before (carefully) and after (dynamically) the catch position. If you take time off the recovery to get a higher rate, you need to be quicker at getting the blades in, but you also need to keep the same timing relationship. Longer discussion left out - it's posted elsewhere. |
| 25 Apr 2008 09:54:46 |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 24, 6:45=A0pm, wmart...@gmail.com wrote: > On Apr 24, 2:37 pm, "Charles Carroll" <charles_carr...@comcast.net> > wrote: > > > > > > > Dear all - > > > While out on the water yesterday morning I may have stumbled on another > > rowing metaphor. Taking a good catch is a like painting a house. =A0Most= of > > the work is in the preparation. > > > Isn't this just as true for rowing? Most of the work is in the preparati= on. > > > To be slightly more specific, it occurs to me that most of the work in > > sculling may be in the recovery, not the drive. > > > Take Volker Nolte's assertion that ". the stroke rate is produced during= the > > recovery." =A0This means that to raise the rate, thus to go faster, you = need > > to speed up the recovery. But whenever I try to speed up the recovery it= has > > the opposite effect. Instead of going faster I go slower. I end up being= > > jerky and tense and checking the boat. On the other hand, when I don't r= ush > > the recovery I tend to go faster because I am smoother and more relaxed.= > > > I think anyone who has sculled knows that it can be hard work to be smoo= th > > and relaxed in the recovery, especially when you are trying to speed up = the > > recovery. For how do you speed up the recovery without slowing down the > > shell? What do you do to pick up the pace of the recovery while staying > > smooth and relaxed? > > > Cordially, > > > Charles > > Carl's got good points as are references to Nolte (Rowing Faster). =A0I > get to watch some pretty good catches on a regular basis with 7 > olympic qualified boats training outside my office window. > That aside. =A0One thing people forget is that even though the oars are > out of the water AND the boat is speeding up during the recovery, the > SYSTEM (boat, blades, rower - the sum of their centres of mass) can do > nothing except slow down when the blades are out of the recovery > unless at that moment you went over a waterfall. =A0With intermitent > propulsion is intermittent non-propulsion, and once the propulsive > phase of the stroke is over, it's just a drag what happens to the > boat ;-) > One thing you can try at the catch - even before you go out on the > water - ask yourself - if the SYSTEM is slowing down, and the BOAT is > going faster, how does it do that? =A0Look at the boat carefully, and > think about how the boat goes faster and "goes past you" while you're > preparing for the next stroke. =A0(here's a hint - it might be where you > put your feet). =A0A little experiment - a) move to and from the catch > position without the blades going in the water =A0(or with them skimming > the surface), and try to pay attention to the movements of the seat - > feet. =A0See if you can make the FOOT STRETCHER move with as little > hesitation as possible at the point of transition from recovery to > drive. =A0When you've managed that, do it again, but watch something > floating next to the boat - THE BOAT moves back and forth beside the > floating object, YOU sit there, moving forward and backward very > little, while your boat moves back and forth. > so - when your feet (in answer to the question above) get to that > "tucked up position" and are about to push again, you want your sticks > to enter the water so that when you start to push (remember, no time > at the catch position), that push on the boat (normally causing it to > want to go backwards) causes the oarlocks/gates/pins to run into the > back of the blade at the wear-plate-collar junction. =A0If the blades > are in the water at this point, the boat moves forward relative to the > motion, if the blades are in the air at this point, the boat moves aft > relative to the motion of the mass centre of the system. > So - put the blades in at full reach - not before, not after... AT > full reach. and keep moving before (carefully) and after (dynamically) > the catch position. > If you take time off the recovery to get a higher rate, you need to be > quicker at getting the blades in, but you also need to keep the same > timing relationship. > > Longer discussion left out - it's posted elsewhere.- Hide quoted text - > > - Show quoted text - Lucky You! Another section of "required reading" in Rowing Faster is the bit by Richard Tonks. IMO, if his short bit on the catch and drive was understood and implemented by a rower, they would be a boat mover, no matter what it looked like externally. Recognizing that the hull must move faster than the system during the recovery, and that this will increase Drag exponentially (which efffects system decelleration proportionally), there must be a way to figure out what sort of optimal ratio should be sought after for best efficiency. Who has the Maths Skills to tackle that monster? (Perhaps a simpler problem could be tackled first, the one that shows that gravity is NOT enough to get the blade in quick enough at the catch. While it gets used quite a lot, I heard it in a coaches clinic recently, the rower that actually does as requested will be late, late, late; perhaps even a bit later than that.) That said, the fastest speeds are not likely to be done while adhering to maximal efficiency, however practicing for maximum efficiency might just keep us closer to that when going faster, and thus allow us to go faster for longer periods of time. I rotated my rowers through in pairs on the C2 + Slides (2-) this morning, most everyone was shocked to find out how out of synch they were in the beginning (banging the ends and such) but they also tended to work it out once they gave up the notion that it was the fault of the slides not being level and focused on getting together by feel instead of by sight (It's almost a zen like state, i.e. "You want to feel that you are alone, and that is when you are together."). Still lots of work to do, but hopefully at least a little bit of feel was acquired through the process. Hopefully they will carry a bit of it to the boat where the connection to the water is a bit tougher than the chain/cog connection on the Erg. Next week I think a Slides 4- will be on the menu. - Paul Smith |
| 25 Apr 2008 19:14:42 |
| John Mulholland |
| Re: Hurrying the recovery - Rushing into the catch |
"Charles Carroll" <charles_carroll@comcast.net > wrote in message news:G7idnUo_FIVEII3VnZ2dnUVZ_v2pnZ2d@comcast.com... > Caroline - > > The pages you want in "Rowing Faster" are 179-181, the Strictly Science > section of Nolte's chapter on the recovery. You'll find the quote on page > 181. > > I think you'll see that these pages provide serious support for what Carl > has been saying about the relationship between the recovery, drive, and > stroke rate. > > Gotta run if I am going to get any sculling in this morning. > > Cordially, > > Charles There you go... rushing to the catch! I believe you should try to speed your hands at the finish. Pull a little harder at the finish, spin the hands and get them moving away quicker. That will naturally increase your speed all the way forward. Of course you should try to keep it smooth and relaxed up to the catch. Increasing the hand speed ten per cent should give you nearly two pips on the rating. -- John Mulholland |
| 25 Apr 2008 20:10:12 |
| Carl Douglas |
| Re: Hurrying the recovery - Rushing into the catch |
paul_v_smith@hotmail.com wrote: > On Apr 24, 6:45 pm, wmart...@gmail.com wrote: > >>On Apr 24, 2:37 pm, "Charles Carroll" <charles_carr...@comcast.net> >>wrote: >> >> >> >> >> >> >>>Dear all - >> >>>While out on the water yesterday morning I may have stumbled on another >>>rowing metaphor. Taking a good catch is a like painting a house. Most of >>>the work is in the preparation. >> >>>Isn't this just as true for rowing? Most of the work is in the preparation. >> >>>To be slightly more specific, it occurs to me that most of the work in >>>sculling may be in the recovery, not the drive. >> >>>Take Volker Nolte's assertion that ". the stroke rate is produced during the >>>recovery." This means that to raise the rate, thus to go faster, you need >>>to speed up the recovery. But whenever I try to speed up the recovery it has >>>the opposite effect. Instead of going faster I go slower. I end up being >>>jerky and tense and checking the boat. On the other hand, when I don't rush >>>the recovery I tend to go faster because I am smoother and more relaxed. >> >>>I think anyone who has sculled knows that it can be hard work to be smooth >>>and relaxed in the recovery, especially when you are trying to speed up the >>>recovery. For how do you speed up the recovery without slowing down the >>>shell? What do you do to pick up the pace of the recovery while staying >>>smooth and relaxed? >> >>>Cordially, >> >>>Charles >> >>Carl's got good points as are references to Nolte (Rowing Faster). I >>get to watch some pretty good catches on a regular basis with 7 >>olympic qualified boats training outside my office window. >>That aside. One thing people forget is that even though the oars are >>out of the water AND the boat is speeding up during the recovery, the >>SYSTEM (boat, blades, rower - the sum of their centres of mass) can do >>nothing except slow down when the blades are out of the recovery >>unless at that moment you went over a waterfall. With intermitent >>propulsion is intermittent non-propulsion, and once the propulsive >>phase of the stroke is over, it's just a drag what happens to the >>boat ;-) >>One thing you can try at the catch - even before you go out on the >>water - ask yourself - if the SYSTEM is slowing down, and the BOAT is >>going faster, how does it do that? Look at the boat carefully, and >>think about how the boat goes faster and "goes past you" while you're >>preparing for the next stroke. (here's a hint - it might be where you >>put your feet). A little experiment - a) move to and from the catch >>position without the blades going in the water (or with them skimming >>the surface), and try to pay attention to the movements of the seat - >>feet. See if you can make the FOOT STRETCHER move with as little >>hesitation as possible at the point of transition from recovery to >>drive. When you've managed that, do it again, but watch something >>floating next to the boat - THE BOAT moves back and forth beside the >>floating object, YOU sit there, moving forward and backward very >>little, while your boat moves back and forth. >>so - when your feet (in answer to the question above) get to that >>"tucked up position" and are about to push again, you want your sticks >>to enter the water so that when you start to push (remember, no time >>at the catch position), that push on the boat (normally causing it to >>want to go backwards) causes the oarlocks/gates/pins to run into the >>back of the blade at the wear-plate-collar junction. If the blades >>are in the water at this point, the boat moves forward relative to the >>motion, if the blades are in the air at this point, the boat moves aft >>relative to the motion of the mass centre of the system. >>So - put the blades in at full reach - not before, not after... AT >>full reach. and keep moving before (carefully) and after (dynamically) >>the catch position. >>If you take time off the recovery to get a higher rate, you need to be >>quicker at getting the blades in, but you also need to keep the same >>timing relationship. >> >>Longer discussion left out - it's posted elsewhere.- Hide quoted text - >> >>- Show quoted text - > > > Lucky You! Another section of "required reading" in Rowing Faster is > the bit by Richard Tonks. IMO, if his short bit on the catch and > drive was understood and implemented by a rower, they would be a boat > mover, no matter what it looked like externally. > > Recognizing that the hull must move faster than the system during the > recovery, and that this will increase Drag exponentially (which > efffects system decelleration proportionally), there must be a way to > figure out what sort of optimal ratio should be sought after for best > efficiency. Who has the Maths Skills to tackle that monster? The hull drag during recovery will only increase if you recover in a manner which applies appropriately more forward force to the boat than the frictional drag it is encountering to increase boat velocity against that quadratic drag vs speed relationship. Accelerating the boat during recovery is not a good idea (yet another reason for not making haste off the finish, BTW) as it does impose a crippling drag penalty, whereas aiming for constant velocity minimises drag losses for a given average speed. What you actually get is a declining velocity, with a sudden dip near the catch which, as you've pointed out in the past, ain't so bad as long as it's kept short. I don't think the maths is too difficult, just messy 'cos of all the different lumps of body which move differently while still part of a complex linkage. It all depends what you want out of the maths, & that depends on the forces you choose to apply at the various links in the body/boat system > (Perhaps a simpler problem could be tackled first, the one that shows > that gravity is NOT enough to get the blade in quick enough at the > catch. While it gets used quite a lot, I heard it in a coaches clinic > recently, the rower that actually does as requested will be late, > late, late; perhaps even a bit later than that.) Dead right on that, Paul. If all the mass of the oar were concentrated at the tip of the blade it would still be too slow in (never mind the fluid resistance as it enters & cuts into the water). For a mass to fall the minimum necessary 23cm (= blade tip width) from static, in vacuum, would take 0.21 seconds. But your blade has its mass fairly near to the pivot point, & a relatively high moment of inertia to boot. Si I'd guess that for the tip to fall that 23cm under gravity would take the very best part of 1 second, even if it didn't have to bury itself into the water. And that supposes you take all the downward force off your hands first, & lift them to keep them our of the way of the rising handles (which gets conveniently forgotten when folk advocate these appealing but naive notions). > > That said, the fastest speeds are not likely to be done while adhering > to maximal efficiency, however practicing for maximum efficiency might > just keep us closer to that when going faster, and thus allow us to go > faster for longer periods of time. Yup. > > I rotated my rowers through in pairs on the C2 + Slides (2-) this > morning, most everyone was shocked to find out how out of synch they > were in the beginning (banging the ends and such) but they also tended > to work it out once they gave up the notion that it was the fault of > the slides not being level and focused on getting together by feel > instead of by sight (It's almost a zen like state, i.e. "You want to > feel that you are alone, and that is when you are together."). Still > lots of work to do, but hopefully at least a little bit of feel was > acquired through the process. Hopefully they will carry a bit of it > to the boat where the connection to the water is a bit tougher than > the chain/cog connection on the Erg. Next week I think a Slides 4- > will be on the menu. > > - Paul Smith Cheers - Carl -- Carl Douglas Racing Shells - Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK Find: http://tinyurl.com/2tqujf Email: carl@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682 URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers) |
| 27 Apr 2008 18:07:44 |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 26, 4:54 am, paul_v_sm...@hotmail.com wrote: > > > - Show quoted text - > > Lucky You! Another section of "required reading" in Rowing Faster is > the bit by Richard Tonks. IMO, if his short bit on the catch and > drive was understood and implemented by a rower, they would be a boat > mover, no matter what it looked like externally. > I think I'm kinda lucky, too. Have read Richard's remarks, and later this week I'm going out in his coach boat with the video camera... 8-) Beautiful day here at Karapiro. W |
| 28 Apr 2008 04:59:03 |
| Paul |
| Re: Hurrying the recovery - Rushing into the catch |
On 25 Apr, 20:10, Carl Douglas <c...@carldouglas.co.uk > wrote: > paul_v_sm...@hotmail.com wrote: > > On Apr 24, 6:45 pm, wmart...@gmail.com wrote: > > >>On Apr 24, 2:37 pm, "Charles Carroll" <charles_carr...@comcast.net> > >>wrote: > > >>>Dear all - > > >>>While out on the water yesterday morning I may have stumbled on another= > >>>rowing metaphor. Taking a good catch is a like painting a house. =A0Mos= t of > >>>the work is in the preparation. > > >>>Isn't this just as true for rowing? Most of the work is in the preparat= ion. > > >>>To be slightly more specific, it occurs to me that most of the work in > >>>sculling may be in the recovery, not the drive. > > >>>Take Volker Nolte's assertion that ". the stroke rate is produced durin= g the > >>>recovery." =A0This means that to raise the rate, thus to go faster, you= need > >>>to speed up the recovery. But whenever I try to speed up the recovery i= t has > >>>the opposite effect. Instead of going faster I go slower. I end up bein= g > >>>jerky and tense and checking the boat. On the other hand, when I don't = rush > >>>the recovery I tend to go faster because I am smoother and more relaxed= . > > >>>I think anyone who has sculled knows that it can be hard work to be smo= oth > >>>and relaxed in the recovery, especially when you are trying to speed up= the > >>>recovery. For how do you speed up the recovery without slowing down the= > >>>shell? What do you do to pick up the pace of the recovery while staying= > >>>smooth and relaxed? > > >>>Cordially, > > >>>Charles > > >>Carl's got good points as are references to Nolte (Rowing Faster). =A0I > >>get to watch some pretty good catches on a regular basis with 7 > >>olympic qualified boats training outside my office window. > >>That aside. =A0One thing people forget is that even though the oars are > >>out of the water AND the boat is speeding up during the recovery, the > >>SYSTEM (boat, blades, rower - the sum of their centres of mass) can do > >>nothing except slow down when the blades are out of the recovery > >>unless at that moment you went over a waterfall. =A0With intermitent > >>propulsion is intermittent non-propulsion, and once the propulsive > >>phase of the stroke is over, it's just a drag what happens to the > >>boat ;-) > >>One thing you can try at the catch - even before you go out on the > >>water - ask yourself - if the SYSTEM is slowing down, and the BOAT is > >>going faster, how does it do that? =A0Look at the boat carefully, and > >>think about how the boat goes faster and "goes past you" while you're > >>preparing for the next stroke. =A0(here's a hint - it might be where you= > >>put your feet). =A0A little experiment - a) move to and from the catch > >>position without the blades going in the water =A0(or with them skimming= > >>the surface), and try to pay attention to the movements of the seat - > >>feet. =A0See if you can make the FOOT STRETCHER move with as little > >>hesitation as possible at the point of transition from recovery to > >>drive. =A0When you've managed that, do it again, but watch something > >>floating next to the boat - THE BOAT moves back and forth beside the > >>floating object, YOU sit there, moving forward and backward very > >>little, while your boat moves back and forth. > >>so - when your feet (in answer to the question above) get to that > >>"tucked up position" and are about to push again, you want your sticks > >>to enter the water so that when you start to push (remember, no time > >>at the catch position), that push on the boat (normally causing it to > >>want to go backwards) causes the oarlocks/gates/pins to run into the > >>back of the blade at the wear-plate-collar junction. =A0If the blades > >>are in the water at this point, the boat moves forward relative to the > >>motion, if the blades are in the air at this point, the boat moves aft > >>relative to the motion of the mass centre of the system. > >>So - put the blades in at full reach - not before, not after... AT > >>full reach. and keep moving before (carefully) and after (dynamically) > >>the catch position. > >>If you take time off the recovery to get a higher rate, you need to be > >>quicker at getting the blades in, but you also need to keep the same > >>timing relationship. > > >>Longer discussion left out - it's posted elsewhere.- Hide quoted text - > > >>- Show quoted text - > > > Lucky You! =A0Another section of "required reading" in Rowing Faster is > > the bit by Richard Tonks. =A0IMO, if his short bit on the catch and > > drive was understood and implemented by a rower, they would be a boat > > mover, no matter what it looked like externally. > > > Recognizing that the hull must move faster than the system during the > > recovery, and that this will increase Drag exponentially (which > > efffects system decelleration proportionally), there must be a way to > > figure out what sort of optimal ratio should be sought after for best > > efficiency. =A0Who has the Maths Skills to tackle that monster? > > The hull drag during recovery will only increase if you recover in a > manner which applies appropriately more forward force to the boat than > the frictional drag it is encountering to increase boat velocity against > that quadratic drag vs speed relationship. =A0Accelerating the boat during= > recovery is not a good idea (yet another reason for not making haste off > the finish, BTW) as it does impose a crippling drag penalty, whereas > aiming for constant velocity minimises drag losses for a given average > speed. =A0What you actually get is a declining velocity, with a sudden dip= > near the catch which, as you've pointed out in the past, ain't so bad as > long as it's kept short. =A0I don't think the maths is too difficult, just= > messy 'cos of all the different lumps of body which move differently > while still part of a complex linkage. =A0It all depends what you want out= > of the maths, & that depends on the forces you choose to apply at the > various links in the body/boat system > > > (Perhaps a simpler problem could be tackled first, the one that shows > > that gravity is NOT enough to get the blade in quick enough at the > > catch. =A0While it gets used quite a lot, I heard it in a coaches clinic= > > recently, the rower that actually does as requested will be late, > > late, late; perhaps even a bit later than that.) > > Dead right on that, Paul. =A0If all the mass of the oar were concentrated > at the tip of the blade it would still be too slow in (never mind the > fluid resistance as it enters & cuts into the water). =A0For a mass to > fall the minimum necessary 23cm (=3D blade tip width) from static, in > vacuum, would take 0.21 seconds. =A0But your blade has its mass fairly > near to the pivot point, & a relatively high moment of inertia to boot. > =A0 Si I'd guess that for the tip to fall that 23cm under gravity would > take the very best part of 1 second, even if it didn't have to bury > itself into the water. =A0And that supposes you take all the downward > force off your hands first, & lift them to keep them our of the way of > the rising handles (which gets conveniently forgotten when folk advocate > these appealing but naive notions). > > > > > That said, the fastest speeds are not likely to be done while adhering > > to maximal efficiency, however practicing for maximum efficiency might > > just keep us closer to that when going faster, and thus allow us to go > > faster for longer periods of time. > > Yup. > > > > > I rotated my rowers through in pairs on the C2 + Slides (2-) this > > morning, most everyone was shocked to find out how out of synch they > > were in the beginning (banging the ends and such) but they also tended > > to work it out once they gave up the notion that it was the fault of > > the slides not being level and focused on getting together by feel > > instead of by sight (It's almost a zen like state, i.e. "You want to > > feel that you are alone, and that is when you are together."). =A0Still > > lots of work to do, but hopefully at least a little bit of feel was > > acquired through the process. =A0Hopefully they will carry a bit of it > > to the boat where the connection to the water is a bit tougher than > > the chain/cog connection on the Erg. =A0Next week I think a Slides 4- > > will be on the menu. > > > - Paul Smith > > Cheers - > Carl > -- > Carl Douglas Racing Shells =A0 =A0 =A0 =A0- > =A0 =A0 =A0Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories= > Write: =A0 Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK > Find: =A0 =A0http://tinyurl.com/2tqujf > Email: c...@carldouglas.co.uk =A0Tel: +44(0)1932-570946 =A0Fax: -563682 > URLs: =A0www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)- Hide q= uoted text - > > - Show quoted text - Carl I am not sure about your math, but it takes a lot less than 1 second for a released blade to bury itself, and the time it takes to bury itself is often less than the time people actually take to put the blade in. Getting people to relax and stop holding the blade back at the catch is a first step, but not in many cases an easy one for people to do. Paul |
| 28 Apr 2008 13:35:22 |
| Carl Douglas |
| Re: Hurrying the recovery - Rushing into the catch |
Paul wrote: > On 25 Apr, 20:10, Carl Douglas <c...@carldouglas.co.uk> wrote: > >>paul_v_sm...@hotmail.com wrote: >> >>>On Apr 24, 6:45 pm, wmart...@gmail.com wrote: >> >>>>On Apr 24, 2:37 pm, "Charles Carroll" <charles_carr...@comcast.net> >>>>wrote: >> >>>>>Dear all - >> >>>>>While out on the water yesterday morning I may have stumbled on another >>>>>rowing metaphor. Taking a good catch is a like painting a house. Most of >>>>>the work is in the preparation. >> >>>>>Isn't this just as true for rowing? Most of the work is in the preparation. >> >>>>>To be slightly more specific, it occurs to me that most of the work in >>>>>sculling may be in the recovery, not the drive. >> >>>>>Take Volker Nolte's assertion that ". the stroke rate is produced during the >>>>>recovery." This means that to raise the rate, thus to go faster, you need >>>>>to speed up the recovery. But whenever I try to speed up the recovery it has >>>>>the opposite effect. Instead of going faster I go slower. I end up being >>>>>jerky and tense and checking the boat. On the other hand, when I don't rush >>>>>the recovery I tend to go faster because I am smoother and more relaxed. >> >>>>>I think anyone who has sculled knows that it can be hard work to be smooth >>>>>and relaxed in the recovery, especially when you are trying to speed up the >>>>>recovery. For how do you speed up the recovery without slowing down the >>>>>shell? What do you do to pick up the pace of the recovery while staying >>>>>smooth and relaxed? >> >>>>>Cordially, >> >>>>>Charles >> >>>>Carl's got good points as are references to Nolte (Rowing Faster). I >>>>get to watch some pretty good catches on a regular basis with 7 >>>>olympic qualified boats training outside my office window. >>>>That aside. One thing people forget is that even though the oars are >>>>out of the water AND the boat is speeding up during the recovery, the >>>>SYSTEM (boat, blades, rower - the sum of their centres of mass) can do >>>>nothing except slow down when the blades are out of the recovery >>>>unless at that moment you went over a waterfall. With intermitent >>>>propulsion is intermittent non-propulsion, and once the propulsive >>>>phase of the stroke is over, it's just a drag what happens to the >>>>boat ;-) >>>>One thing you can try at the catch - even before you go out on the >>>>water - ask yourself - if the SYSTEM is slowing down, and the BOAT is >>>>going faster, how does it do that? Look at the boat carefully, and >>>>think about how the boat goes faster and "goes past you" while you're >>>>preparing for the next stroke. (here's a hint - it might be where you >>>>put your feet). A little experiment - a) move to and from the catch >>>>position without the blades going in the water (or with them skimming >>>>the surface), and try to pay attention to the movements of the seat - >>>>feet. See if you can make the FOOT STRETCHER move with as little >>>>hesitation as possible at the point of transition from recovery to >>>>drive. When you've managed that, do it again, but watch something >>>>floating next to the boat - THE BOAT moves back and forth beside the >>>>floating object, YOU sit there, moving forward and backward very >>>>little, while your boat moves back and forth. >>>>so - when your feet (in answer to the question above) get to that >>>>"tucked up position" and are about to push again, you want your sticks >>>>to enter the water so that when you start to push (remember, no time >>>>at the catch position), that push on the boat (normally causing it to >>>>want to go backwards) causes the oarlocks/gates/pins to run into the >>>>back of the blade at the wear-plate-collar junction. If the blades >>>>are in the water at this point, the boat moves forward relative to the >>>>motion, if the blades are in the air at this point, the boat moves aft >>>>relative to the motion of the mass centre of the system. >>>>So - put the blades in at full reach - not before, not after... AT >>>>full reach. and keep moving before (carefully) and after (dynamically) >>>>the catch position. >>>>If you take time off the recovery to get a higher rate, you need to be >>>>quicker at getting the blades in, but you also need to keep the same >>>>timing relationship. >> >>>>Longer discussion left out - it's posted elsewhere.- Hide quoted text - >> >>>>- Show quoted text - >> >>>Lucky You! Another section of "required reading" in Rowing Faster is >>>the bit by Richard Tonks. IMO, if his short bit on the catch and >>>drive was understood and implemented by a rower, they would be a boat >>>mover, no matter what it looked like externally. >> >>>Recognizing that the hull must move faster than the system during the >>>recovery, and that this will increase Drag exponentially (which >>>efffects system decelleration proportionally), there must be a way to >>>figure out what sort of optimal ratio should be sought after for best >>>efficiency. Who has the Maths Skills to tackle that monster? >> >>The hull drag during recovery will only increase if you recover in a >>manner which applies appropriately more forward force to the boat than >>the frictional drag it is encountering to increase boat velocity against >>that quadratic drag vs speed relationship. Accelerating the boat during >>recovery is not a good idea (yet another reason for not making haste off >>the finish, BTW) as it does impose a crippling drag penalty, whereas >>aiming for constant velocity minimises drag losses for a given average >>speed. What you actually get is a declining velocity, with a sudden dip >>near the catch which, as you've pointed out in the past, ain't so bad as >>long as it's kept short. I don't think the maths is too difficult, just >>messy 'cos of all the different lumps of body which move differently >>while still part of a complex linkage. It all depends what you want out >>of the maths, & that depends on the forces you choose to apply at the >>various links in the body/boat system >> >> >>>(Perhaps a simpler problem could be tackled first, the one that shows >>>that gravity is NOT enough to get the blade in quick enough at the >>>catch. While it gets used quite a lot, I heard it in a coaches clinic >>>recently, the rower that actually does as requested will be late, >>>late, late; perhaps even a bit later than that.) >> >>Dead right on that, Paul. If all the mass of the oar were concentrated >>at the tip of the blade it would still be too slow in (never mind the >>fluid resistance as it enters & cuts into the water). For a mass to >>fall the minimum necessary 23cm (= blade tip width) from static, in >>vacuum, would take 0.21 seconds. But your blade has its mass fairly >>near to the pivot point, & a relatively high moment of inertia to boot. >> Si I'd guess that for the tip to fall that 23cm under gravity would >>take the very best part of 1 second, even if it didn't have to bury >>itself into the water. And that supposes you take all the downward >>force off your hands first, & lift them to keep them our of the way of >>the rising handles (which gets conveniently forgotten when folk advocate >>these appealing but naive notions). >> >> >> >> >>>That said, the fastest speeds are not likely to be done while adhering >>>to maximal efficiency, however practicing for maximum efficiency might >>>just keep us closer to that when going faster, and thus allow us to go >>>faster for longer periods of time. >> >>Yup. >> >> >> >> >>>I rotated my rowers through in pairs on the C2 + Slides (2-) this >>>morning, most everyone was shocked to find out how out of synch they >>>were in the beginning (banging the ends and such) but they also tended >>>to work it out once they gave up the notion that it was the fault of >>>the slides not being level and focused on getting together by feel >>>instead of by sight (It's almost a zen like state, i.e. "You want to >>>feel that you are alone, and that is when you are together."). Still >>>lots of work to do, but hopefully at least a little bit of feel was >>>acquired through the process. Hopefully they will carry a bit of it >>>to the boat where the connection to the water is a bit tougher than >>>the chain/cog connection on the Erg. Next week I think a Slides 4- >>>will be on the menu. >> >>>- Paul Smith >> >>Cheers - >>Carl >>-- >>Carl Douglas Racing Shells - >> Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories >>Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK >>Find: http://tinyurl.com/2tqujf >>Email: c...@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682 >>URLs: www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)- Hide quoted text - >> >>- Show quoted text - > > > Carl > > I am not sure about your math, Here it is:- A standard equation for motion under acceleration is: s = ut + 0.5ft^2 Insert the known data: s = distance to move = 0.23 metres u = initial velocity (in direction of fall) = 0 metres/sec f = acceleration = 9.81 metres/sec^2 (acceleration due to gravity) t = time of fall - the unknown Thus: 0.23 = 0 * t + 0.5 * 9.81 * t^2 And rearranging gives us: t^2 = 0.23/4.905 = 0.0469 t = 0.217 seconds but it takes a lot less than 1 second > for a released blade to bury itself, but you have less than 1 second to complete catch, stroke & extraction and the time it takes to bury > itself is often less than the time people actually take to put the > blade in. Getting people to relax and stop holding the blade back at > the catch is a first step, but not in many cases an easy one for > people to do. I couldn't agree more there. The problem is: how to get them to relax? Telling them to relax can be pretty counterproductive, but telling them the wrong things to do may get them to relax but instil the mistaken belief that the blade can be allowed to just fall into the catch - & then they tell others the same Life is so tough! Cheers - Carl -- Carl Douglas Racing Shells - Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK Find: http://tinyurl.com/2tqujf Email: carl@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682 URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers) |
| 28 Apr 2008 07:20:11 |
| Paul |
| Re: Hurrying the recovery - Rushing into the catch |
On 28 Apr, 13:35, Carl Douglas <c...@carldouglas.co.uk > wrote: > Paul wrote: > > On 25 Apr, 20:10, Carl Douglas <c...@carldouglas.co.uk> wrote: > > >>paul_v_sm...@hotmail.com wrote: > > >>>On Apr 24, 6:45 pm, wmart...@gmail.com wrote: > > >>>>On Apr 24, 2:37 pm, "Charles Carroll" <charles_carr...@comcast.net> > >>>>wrote: > > >>>>>Dear all - > > >>>>>While out on the water yesterday morning I may have stumbled on anoth= er > >>>>>rowing metaphor. Taking a good catch is a like painting a house. =A0M= ost of > >>>>>the work is in the preparation. > > >>>>>Isn't this just as true for rowing? Most of the work is in the prepar= ation. > > >>>>>To be slightly more specific, it occurs to me that most of the work i= n > >>>>>sculling may be in the recovery, not the drive. > > >>>>>Take Volker Nolte's assertion that ". the stroke rate is produced dur= ing the > >>>>>recovery." =A0This means that to raise the rate, thus to go faster, y= ou need > >>>>>to speed up the recovery. But whenever I try to speed up the recovery= it has > >>>>>the opposite effect. Instead of going faster I go slower. I end up be= ing > >>>>>jerky and tense and checking the boat. On the other hand, when I don'= t rush > >>>>>the recovery I tend to go faster because I am smoother and more relax= ed. > > >>>>>I think anyone who has sculled knows that it can be hard work to be s= mooth > >>>>>and relaxed in the recovery, especially when you are trying to speed = up the > >>>>>recovery. For how do you speed up the recovery without slowing down t= he > >>>>>shell? What do you do to pick up the pace of the recovery while stayi= ng > >>>>>smooth and relaxed? > > >>>>>Cordially, > > >>>>>Charles > > >>>>Carl's got good points as are references to Nolte (Rowing Faster). =A0= I > >>>>get to watch some pretty good catches on a regular basis with 7 > >>>>olympic qualified boats training outside my office window. > >>>>That aside. =A0One thing people forget is that even though the oars ar= e > >>>>out of the water AND the boat is speeding up during the recovery, the > >>>>SYSTEM (boat, blades, rower - the sum of their centres of mass) can do= > >>>>nothing except slow down when the blades are out of the recovery > >>>>unless at that moment you went over a waterfall. =A0With intermitent > >>>>propulsion is intermittent non-propulsion, and once the propulsive > >>>>phase of the stroke is over, it's just a drag what happens to the > >>>>boat ;-) > >>>>One thing you can try at the catch - even before you go out on the > >>>>water - ask yourself - if the SYSTEM is slowing down, and the BOAT is > >>>>going faster, how does it do that? =A0Look at the boat carefully, and > >>>>think about how the boat goes faster and "goes past you" while you're > >>>>preparing for the next stroke. =A0(here's a hint - it might be where y= ou > >>>>put your feet). =A0A little experiment - a) move to and from the catch= > >>>>position without the blades going in the water =A0(or with them skimmi= ng > >>>>the surface), and try to pay attention to the movements of the seat - > >>>>feet. =A0See if you can make the FOOT STRETCHER move with as little > >>>>hesitation as possible at the point of transition from recovery to > >>>>drive. =A0When you've managed that, do it again, but watch something > >>>>floating next to the boat - THE BOAT moves back and forth beside the > >>>>floating object, YOU sit there, moving forward and backward very > >>>>little, while your boat moves back and forth. > >>>>so - when your feet (in answer to the question above) get to that > >>>>"tucked up position" and are about to push again, you want your sticks= > >>>>to enter the water so that when you start to push (remember, no time > >>>>at the catch position), that push on the boat (normally causing it to > >>>>want to go backwards) causes the oarlocks/gates/pins to run into the > >>>>back of the blade at the wear-plate-collar junction. =A0If the blades > >>>>are in the water at this point, the boat moves forward relative to the= > >>>>motion, if the blades are in the air at this point, the boat moves aft= > >>>>relative to the motion of the mass centre of the system. > >>>>So - put the blades in at full reach - not before, not after... AT > >>>>full reach. and keep moving before (carefully) and after (dynamically)= > >>>>the catch position. > >>>>If you take time off the recovery to get a higher rate, you need to be= > >>>>quicker at getting the blades in, but you also need to keep the same > >>>>timing relationship. > > >>>>Longer discussion left out - it's posted elsewhere.- Hide quoted text = - > > >>>>- Show quoted text - > > >>>Lucky You! =A0Another section of "required reading" in Rowing Faster is= > >>>the bit by Richard Tonks. =A0IMO, if his short bit on the catch and > >>>drive was understood and implemented by a rower, they would be a boat > >>>mover, no matter what it looked like externally. > > >>>Recognizing that the hull must move faster than the system during the > >>>recovery, and that this will increase Drag exponentially (which > >>>efffects system decelleration proportionally), there must be a way to > >>>figure out what sort of optimal ratio should be sought after for best > >>>efficiency. =A0Who has the Maths Skills to tackle that monster? > > >>The hull drag during recovery will only increase if you recover in a > >>manner which applies appropriately more forward force to the boat than > >>the frictional drag it is encountering to increase boat velocity against= > >>that quadratic drag vs speed relationship. =A0Accelerating the boat duri= ng > >>recovery is not a good idea (yet another reason for not making haste off= > >>the finish, BTW) as it does impose a crippling drag penalty, whereas > >>aiming for constant velocity minimises drag losses for a given average > >>speed. =A0What you actually get is a declining velocity, with a sudden d= ip > >>near the catch which, as you've pointed out in the past, ain't so bad as= > >>long as it's kept short. =A0I don't think the maths is too difficult, ju= st > >>messy 'cos of all the different lumps of body which move differently > >>while still part of a complex linkage. =A0It all depends what you want o= ut > >>of the maths, & that depends on the forces you choose to apply at the > >>various links in the body/boat system > > >>>(Perhaps a simpler problem could be tackled first, the one that shows > >>>that gravity is NOT enough to get the blade in quick enough at the > >>>catch. =A0While it gets used quite a lot, I heard it in a coaches clini= c > >>>recently, the rower that actually does as requested will be late, > >>>late, late; perhaps even a bit later than that.) > > >>Dead right on that, Paul. =A0If all the mass of the oar were concentrate= d > >>at the tip of the blade it would still be too slow in (never mind the > >>fluid resistance as it enters & cuts into the water). =A0For a mass to > >>fall the minimum necessary 23cm (=3D blade tip width) from static, in > >>vacuum, would take 0.21 seconds. =A0But your blade has its mass fairly > >>near to the pivot point, & a relatively high moment of inertia to boot. > >> =A0Si I'd guess that for the tip to fall that 23cm under gravity would > >>take the very best part of 1 second, even if it didn't have to bury > >>itself into the water. =A0And that supposes you take all the downward > >>force off your hands first, & lift them to keep them our of the way of > >>the rising handles (which gets conveniently forgotten when folk advocate= > >>these appealing but naive notions). > > >>>That said, the fastest speeds are not likely to be done while adhering > >>>to maximal efficiency, however practicing for maximum efficiency might > >>>just keep us closer to that when going faster, and thus allow us to go > >>>faster for longer periods of time. > > >>Yup. > > >>>I rotated my rowers through in pairs on the C2 + Slides (2-) this > >>>morning, most everyone was shocked to find out how out of synch they > >>>were in the beginning (banging the ends and such) but they also tended > >>>to work it out once they gave up the notion that it was the fault of > >>>the slides not being level and focused on getting together by feel > >>>instead of by sight (It's almost a zen like state, i.e. "You want to > >>>feel that you are alone, and that is when you are together."). =A0Still= > >>>lots of work to do, but hopefully at least a little bit of feel was > >>>acquired through the process. =A0Hopefully they will carry a bit of it > >>>to the boat where the connection to the water is a bit tougher than > >>>the chain/cog connection on the Erg. =A0Next week I think a Slides 4- > >>>will be on the menu. > > >>>- Paul Smith > > >>Cheers - > >>Carl > >>-- > >>Carl Douglas Racing Shells =A0 =A0 =A0 =A0- > >> =A0 =A0 Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories= > >>Write: =A0 Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK > >>Find: =A0 =A0http://tinyurl.com/2tqujf > >>Email: c...@carldouglas.co.uk =A0Tel: +44(0)1932-570946 =A0Fax: -563682 > >>URLs: =A0www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)-Hide = quoted text - > > >>- Show quoted text - > > > Carl > > > I am not sure about your math, > > Here it is:- > A standard equation for motion under acceleration is: > =A0 =A0 =A0s =3D ut + 0.5ft^2 > Insert the known data: > =A0 =A0 =A0s =3D distance to move =3D 0.23 metres > =A0 =A0 =A0u =3D initial velocity (in direction of fall) =3D 0 metres/sec > =A0 =A0 =A0f =3D acceleration =3D 9.81 metres/sec^2 (acceleration due to g= ravity) > =A0 =A0 =A0t =3D time of fall - the unknown > Thus: > =A0 =A0 =A00.23 =3D 0 * t + 0.5 * 9.81 * t^2 > And rearranging gives us: > =A0 =A0 =A0t^2 =3D 0.23/4.905 =3D 0.0469 > =A0 =A0 =A0t =3D =A00.217 seconds > > =A0 but it takes a lot less than 1 second > > > for a released blade to bury itself, > > but you have less than 1 second to complete catch, stroke & extraction > > =A0 and the time it takes to bury > > > itself is often less than the time people actually take to put the > > blade in. Getting people to relax and stop holding the blade back at > > the catch is a first step, but not in many cases an easy one for > > people to do. > > I couldn't agree more there. > > The problem is: =A0how to get them to relax? =A0Telling them to relax can = be > pretty counterproductive, but telling them the =A0wrong things to do may > get them to relax but instil the mistaken belief that the blade can be > allowed to just fall into the catch - & then they tell others the same > > Life is so tough! > > Cheers - > Carl > > -- > Carl Douglas Racing Shells =A0 =A0 > ... > > read more =BB- Hide quoted text - > > - Show quoted text - I find this one of the most difficult parts of the stroke to coach because people can't feel when they are doing it right, at least initially. They have to be told, stroke by stroke. I usualy try a range of different approaches/excersises. What works really well with one person is often totally useless for the next. I tend to use the 'let the blade fall in' thing as a illustration - look how fast it falls in on its own, thats much faster than you are putting it in, you are actually holding it back etc. etc. |
| 28 Apr 2008 10:37:42 |
| Charles Carroll |
| Re: Hurrying the recovery - Rushing into the catch |
Carl - I don't know about life's being tough, but I do know how tough it is to be relaxed while you are sculling. When I think about all the rowing and sculling videos I have seen, and the scullers I have watched while I have been on the water, it occurs to me that the very best may have one, and only one, thing in common: being relaxed. This seems especially true for the recovery. Scull long enough and you may become really good and develop a technique uniquely your own, but you will still have one thing in common with other really good scullers and that is a smooth, relaxed recovery. Is this why elite scullers rowing at high rates in high stake races make it look easy? It seems to me that your question, "how do you get them to relax," is the central question. I wonder if Fairbairn may have the right idea about this when he advises "row to your strong point?" In any event, following his advice and rowing only to my strong point seems to be working for me, leastwise at the moment. But now the question becomes, what is your strong point? I'll quote Fairbairn: "Do not exaggerate in order to row longer. "Coaches and oarsmen are very apt to try and exaggerate. Length is the main thing in rowing; so coaches and oarsmen are apt to try and get longer. Rowing is an endless chain movement. The diameter of that movement varies according to the oarsman's proficiency and fitness. I call it diameter to accentuate and possibly exaggerate the importance of the circular movements. The length of the oarsman's endless chain movement is what I call rowing to his strong point. Rowing true is the only way to learn, and to do this the oarsman must work the oar correctly and only row to his strong point. That is the point from which he can row the blade through with a springing hit, and elastic draw, without feeling any heaviness or effort. His Subjective Mind knows where his strong point is, and as he rows the blade through truly from his strong point, thus his strong point will become a longer point, till at last his strong point will be the longest point to which he can reach. Trying to row to a longer point-beloved by coaches and oarsmen-kills the endless chain movement, kills the rhythm or harmony. The weight comes off; the spring and momentum die; the oar is lugged through in jerks, and the stroke is dead and heavy. So, oarsman, row to your strong point, never bite off more than you can chew, and your rowing will improve quickly." That's Fairbairn's idea of what "the strong point" is. For me the idea of the strong point is slightly less complicated. Your strong point is simply that point in the stroke when you are still relaxed. That point before you begin to exaggerate and become tense! And telling people to row to their strong point is how you get people to relax. Cordially, Charles |
| 29 Apr 2008 09:48:15 |
| A Browne |
| Re: Hurrying the recovery - Rushing into the catch |
wmartind@gmail.com said the following on 25/04/2008 02:45: <-- Much snippage of excellent stuff -- > > If you take time off the recovery to get a higher rate, you need to be > quicker at getting the blades in, but you also need to keep the same > timing relationship. > > Longer discussion left out - it's posted elsewhere. Not for the first time, a brilliant explanation of something we all think we understand perfectly, but find hard to explain. Nice. Alistair |
| 29 Apr 2008 14:50:42 |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 27, 6:07=A0pm, wmart...@gmail.com wrote: > On Apr 26, 4:54 am, paul_v_sm...@hotmail.com wrote: > > > > > > - Show quoted text - > > > Lucky You! =A0Another section of "required reading" in Rowing Faster is > > the bit by Richard Tonks. =A0IMO, if his short bit on the catch and > > drive was understood and implemented by a rower, they would be a boat > > mover, no matter what it looked like externally. > > I think I'm kinda lucky, too. =A0Have read Richard's remarks, and later > this week I'm going out in his coach boat with the video camera... 8-) > Beautiful day here at Karapiro. > W Would you be so kind as to ask him about this exact passage from Rowing Faster? (pg:169, Heading:Drive, Sentence 1): "Rowers who train on a riveer know that leg speed at the catch depends on whether they're rowing with or against the current." As I misunderstand it, whether rowing with, against, or across a current, I can come up with no reason why any differences would be encountered regarding the quickness of the legs. - Paul Smith |
| 30 Apr 2008 21:16:57 |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 30, 9:50 am, paul_v_sm...@hotmail.com wrote: > On Apr 27, 6:07 pm, wmart...@gmail.com wrote: > > > On Apr 26, 4:54 am, paul_v_sm...@hotmail.com wrote: > > > > > - Show quoted text - > > > > Lucky You! Another section of "required reading" in Rowing Faster is > > > the bit by Richard Tonks. IMO, if his short bit on the catch and > > > drive was understood and implemented by a rower, they would be a boat > > > mover, no matter what it looked like externally. > > > I think I'm kinda lucky, too. Have read Richard's remarks, and later > > this week I'm going out in his coach boat with the video camera... 8-) > > Beautiful day here at Karapiro. > > W > > Would you be so kind as to ask him about this exact passage from > Rowing Faster? > (pg:169, Heading:Drive, Sentence 1): > "Rowers who train on a riveer know that leg speed at the catch depends > on whether they're rowing with or against the current." > > As I misunderstand it, whether rowing with, against, or across a > current, I can come up with no reason why any differences would be > encountered regarding the quickness of the legs. > > - Paul Smith Oops.. Didn't see that query until after.. Will have to re-read it to see if I misunderstand it too. (Fortunately for me, Dick and I seem to think along similar lines about technique - I just use different language to express it, having learned what little I know about rowing during a masters...) |
| 02 May 2008 10:50:01 |
| Re: Hurrying the recovery - Rushing into the catch |
On Apr 30, 9:16=A0pm, wmart...@gmail.com wrote: > On Apr 30, 9:50 am, paul_v_sm...@hotmail.com wrote: > > > > > > > On Apr 27, 6:07 pm, wmart...@gmail.com wrote: > > > > On Apr 26, 4:54 am, paul_v_sm...@hotmail.com wrote: > > > > > > - Show quoted text - > > > > > Lucky You! =A0Another section of "required reading" in Rowing Faster= is > > > > the bit by Richard Tonks. =A0IMO, if his short bit on the catch and > > > > drive was understood and implemented by a rower, they would be a boa= t > > > > mover, no matter what it looked like externally. > > > > I think I'm kinda lucky, too. =A0Have read Richard's remarks, and late= r > > > this week I'm going out in his coach boat with the video camera... 8-)= > > > Beautiful day here at Karapiro. > > > W > > > Would you be so kind as to ask him about this exact passage from > > Rowing Faster? > > (pg:169, Heading:Drive, Sentence 1): > > "Rowers who train on a riveer know that leg speed at the catch depends > > on whether they're rowing with or against the current." > > > As I misunderstand it, whether rowing with, against, or across a > > current, I can come up with no reason why any differences would be > > encountered regarding the quickness of the legs. > > > - Paul Smith > > Oops.. Didn't see that query until after.. Will have to re-read it to > see if I misunderstand it too. =A0(Fortunately for me, Dick and I seem > to think along similar lines about technique - I just use different > language to express it, having learned what little I know about rowing > during a masters...)- Hide quoted text - > > - Show quoted text - Thanks, I'll look forward to your take on it (as well as the authors). I have a tough time putting language to many of the things rowing, having learned what little I know from actual hands on handles, moving boats on lakes (for the most part). I've had a few outings on rivers and noticed sensations that were a little strange from a visual perception sense (which is quite dominant for most humans, and can override our other senses realtively easily). Additional thoughts have been provoked by reading some rather complete books (IMO) written by folks whom seemed to care about figuring out what really goes on in rowing. And as you imply, there are many ways to describe what is happening, always flavored by the knowlege base of the person creating the description. Most all that I've seen seem to be close in same basic principles, but vary enough in description to create endless, and sometimes heated, debate. Some descriptions are completely wrong as far as reality is concerned (i.e. "Let the blade fall in under the force of gravity"), but as noted by others, seem to improve getting the desired effect (getting the blade covered 6 times quicker than gravity would do, at the apex of the achieved reach). - Paul Smith |
| 02 May 2008 15:00:03 |
| Charles Carroll |
| Re: Hurrying the recovery - Rushing into the catch |
Paul - Now wait a second. Who knows less about rowing? You or Walter? I have had a pet theory about the kind of personality attracted to rowing. It comes from observations over the years while washing down boats and eavesdropping on conversations. My theory is that rowers are among the most competitive people I have ever known. I have seen rowers compete over who's the fastest? Who has the best boat? The best oars? Who knows more about blade shapes? Who has the best idea of the difference between power vs. force? Etc. Etc. Etc. I have even eavesdropping on a conversation where two people have competed over who is the worst rower. Now it appears that I am eavesdropping on a conversation where two people are competing over who knows less about rowing. Amazing! Cordially, Charles |
| 02 May 2008 17:06:18 |
| Charles Carroll |
| Re: Hurrying the recovery - Rushing into the catch |
Did I write that it now appears that I am eavesdropping on a conversation where two people are competing over who knows less about rowing? I might add that in this particular competition I am the champion. When it comes to a showdown on who knows less about rowing no one is even in my league. I win this one hands down. |
| 02 May 2008 17:14:12 |
| Re: Hurrying the recovery - Rushing into the catch |
On May 2, 3:00 pm, "Charles Carroll" <charles_carr...@comcast.net > wrote: > Paul - > > Now wait a second. Who knows less about rowing? You or Walter? > > I have had a pet theory about the kind of personality attracted to rowing. > It comes from observations over the years while washing down boats and > eavesdropping on conversations. > > My theory is that rowers are among the most competitive people I have ever > known. I have seen rowers compete over who's the fastest? Who has the best > boat? The best oars? Who knows more about blade shapes? Who has the best > idea of the difference between power vs. force? Etc. Etc. Etc. > > I have even eavesdropping on a conversation where two people have competed > over who is the worst rower. > > Now it appears that I am eavesdropping on a conversation where two people > are competing over who knows less about rowing. > > Amazing! > > Cordially, > > Charles It's not so much that either of us know so little about rowing, it's that we both know a good deal about shooting (not that there is terribly much to know about ballistics, especially since the internal bits are kind of chaotic, we're stuck with making reasonable guesses.). [;o) But back to the misunderstandings of Rowing, it would seem that all we can do is strive to reduce our various spheres of misunderstanding to tolerable levels, for each time that someone says they "know something" it sparks that heated debate mentioned. I like that sort of thing, but not everyone shares in my enthusiasm for provocative debate. - Paul Smith |
| 04 May 2008 03:18:33 |
| Re: Hurrying the recovery - Rushing into the catch |
On May 3, 12:14 pm, paul_v_sm...@hotmail.com wrote: > On May 2, 3:00 pm, "Charles Carroll" <charles_carr...@comcast.net> > wrote: > > > > > Paul - > > > Now wait a second. Who knows less about rowing? You or Walter? > > > I have had a pet theory about the kind of personality attracted to rowing. > > It comes from observations over the years while washing down boats and > > eavesdropping on conversations. > > > My theory is that rowers are among the most competitive people I have ever > > known. I have seen rowers compete over who's the fastest? Who has the best > > boat? The best oars? Who knows more about blade shapes? Who has the best > > idea of the difference between power vs. force? Etc. Etc. Etc. > > > I have even eavesdropping on a conversation where two people have competed > > over who is the worst rower. > > > Now it appears that I am eavesdropping on a conversation where two people > > are competing over who knows less about rowing. > > > Amazing! > > > Cordially, > > > Charles > > It's not so much that either of us know so little about rowing, it's > that we both know a good deal about shooting (not that there is > terribly much to know about ballistics, especially since the internal > bits are kind of chaotic, we're stuck with making reasonable > guesses.). [;o) > > But back to the misunderstandings of Rowing, it would seem that all we > can do is strive to reduce our various spheres of misunderstanding to > tolerable levels, for each time that someone says they "know > something" it sparks that heated debate mentioned. I like that sort > of thing, but not everyone shares in my enthusiasm for provocative > debate. > > - Paul Smith Oh well. Just to P-O some tree huggers - we were out about 10 days ago and got 16 possoms near Pyes Pa. We could only collect about 10 of them because the others fell into some pretty rugged country or behind deer fences. $120NZ for a kg of possom hair - that's about 15 animals.. Blended with Merino wool, it's probably the warmest and softest garment you'll find. Apparently the fellows thought I was a pretty decent shot and want to do this again. (for the non-Kiwis in this NG, the possom is to New Zealand's vegetation almost what the bubonic plague flea was to European people, way back when, so if you kill LOTS of possoms, you're a good Kiwi). I've just finished conducting a coaching course in Wanganui, where they row on a river. We discussed upstream vs. downstream feeling and boat speed. One coach has lots of experience with impeller based speed monitors, and reports that the boat doesn't really know the difference between upstream vs. downstream relative to the water. However people in the boat report tending to feel heavier at the catch going with the current, and lighter (need to be quicker to "lock up") at the catch going upstream. Of course, they discuss tide rather than current, because the tide goes quite a way up the river.. While I've studied some aspects of rowing myself, and I'm happy to take on whatever knowledge is research-generated (and I usually remember to acknowledge the source when I'm describing things), I don't claim to know it "all". I'm WAY too slow of mind to do the optimisation research. One of the early computer-driven optimisation studies was done in South Africa, where they did a study of kicking a target at waist height. The study subject was essentially constrained (tied in place except his leg) and he had a weight attached to his foot so that he couldn't move too fast to study, and it required 28 (IIRC) hours of cpu time on a PDP11 computing more than 20 differential equations with more than 20 variables. (old unix based computer, but it was pretty top-o-the-line in the late 70s). That's for a tightly constrained kick. The rowing movement with both legs, the trunk/head/neck and both arms doing 3D movement in a changing environment on a moving boat, with all of the muscle groups working, joints moving, emg firing, etc., (and etc covers a lot of things), the optimisation study of sculling is possibly not done yet.Then there's rowing. Computers are faster now but someone still has to put things together to do the inertial and theoretical muscle contraction speeds etc., whilst the current level of research is still largely at the descriptive stage. It's nearly a decade ago that I asked a fluid dynamics specialist about the theoretical aspects of blade entry. He thought about it for a couple of days, and said that it's really complex and he didn't have the time or money to think about it (he was at our Aikido club, not a rower). Any time you learn something new, it's usually good for generating more questions. W |
| 04 May 2008 15:06:05 |
| Carl Douglas |
| Re: Hurrying the recovery - Rushing into the catch |
wmartind@gmail.com wrote: > On May 3, 12:14 pm, paul_v_sm...@hotmail.com wrote: > >>On May 2, 3:00 pm, "Charles Carroll" <charles_carr...@comcast.net> >>wrote: >> >> >> >> >>>Paul - >> >>>Now wait a second. Who knows less about rowing? You or Walter? >> >>>I have had a pet theory about the kind of personality attracted to rowing. >>>It comes from observations over the years while washing down boats and >>>eavesdropping on conversations. >> >>>My theory is that rowers are among the most competitive people I have ever >>>known. I have seen rowers compete over who's the fastest? Who has the best >>>boat? The best oars? Who knows more about blade shapes? Who has the best >>>idea of the difference between power vs. force? Etc. Etc. Etc. >> >>>I have even eavesdropping on a conversation where two people have competed >>>over who is the worst rower. >> >>>Now it appears that I am eavesdropping on a conversation where two people >>>are competing over who knows less about rowing. >> >>>Amazing! >> >>>Cordially, >> >>>Charles >> >>It's not so much that either of us know so little about rowing, it's >>that we both know a good deal about shooting (not that there is >>terribly much to know about ballistics, especially since the internal >>bits are kind of chaotic, we're stuck with making reasonable >>guesses.). [;o) >> >>But back to the misunderstandings of Rowing, it would seem that all we >>can do is strive to reduce our various spheres of misunderstanding to >>tolerable levels, for each time that someone says they "know >>something" it sparks that heated debate mentioned. I like that sort >>of thing, but not everyone shares in my enthusiasm for provocative >>debate. >> >>- Paul Smith > > > Oh well. Just to P-O some tree huggers - we were out about 10 days > ago and got 16 possoms near Pyes Pa. We could only collect about 10 > of them because the others fell into some pretty rugged country or > behind deer fences. $120NZ for a kg of possom hair - that's about 15 > animals.. Blended with Merino wool, it's probably the warmest and > softest garment you'll find. Apparently the fellows thought I was a > pretty decent shot and want to do this again. (for the non-Kiwis in > this NG, the possom is to New Zealand's vegetation almost what the > bubonic plague flea was to European people, way back when, so if you > kill LOTS of possoms, you're a good Kiwi). Wasn't the possum foolishly imported from that bigger island over to your left? Just like the fox, rabbit, sheep - & the white man - whom the Brits thought it'd be clever to send there. And, of course, rats went everywhere that sailors ventured. Not to mention the grey squirrel brought to England from N America, & the mink, & the ever growing flocks of green parakeets (from Oz) that infest this locality. Perhaps a bit more tree-hugging at the right time, a bit more forethought on the likely influence of imported species? Nah! We don't do that kind of thinking! And no amount of artillery will reverse the irreversible. > > I've just finished conducting a coaching course in Wanganui, where > they row on a river. We discussed upstream vs. downstream feeling and > boat speed. One coach has lots of experience with impeller based > speed monitors, and reports that the boat doesn't really know the > difference between upstream vs. downstream relative to the water. > However people in the boat report tending to feel heavier at the catch > going with the current, and lighter (need to be quicker to "lock up") > at the catch going upstream. Of course, they discuss tide rather than > current, because the tide goes quite a way up the river.. Which demonstrates the importance of double-blind testing. Only when a rower can't tell which way the water is flowing can you eliminate the judgement-impairing influence of what their eyes try to tell them. And, of course, we all like to kid ourselves that we contribute a bit of unique personal magic to the mundane mechanics of our rowing. > > While I've studied some aspects of rowing myself, and I'm happy to > take on whatever knowledge is research-generated (and I usually > remember to acknowledge the source when I'm describing things), I > don't claim to know it "all". I'm WAY too slow of mind to do the > optimisation research. One of the early computer-driven optimisation > studies was done in South Africa, where they did a study of kicking a > target at waist height. The study subject was essentially constrained > (tied in place except his leg) and he had a weight attached to his > foot so that he couldn't move too fast to study, and it required 28 > (IIRC) hours of cpu time on a PDP11 computing more than 20 > differential equations with more than 20 variables. (old unix based > computer, but it was pretty top-o-the-line in the late 70s). That's > for a tightly constrained kick. The rowing movement with both legs, > the trunk/head/neck and both arms doing 3D movement in a changing > environment on a moving boat, with all of the muscle groups working, > joints moving, emg firing, etc., (and etc covers a lot of things), the > optimisation study of sculling is possibly not done yet.Then there's > rowing. > Computers are faster now but someone still has to put things together > to do the inertial and theoretical muscle contraction speeds etc., > whilst the current level of research is still largely at the > descriptive stage. It's nearly a decade ago that I asked a fluid > dynamics specialist about the theoretical aspects of blade entry. He > thought about it for a couple of days, and said that it's really > complex and he didn't have the time or money to think about it I spent a day, about 11 years back, discussing blade fluid dynamics with a UK firm known for their CFD competence. At that time they said they could handle steady-state computations for any given blade position & loading, which might give useful insights, but agreed this was very different from the real problem of analysing the dynamic, transient (non-steady-state) & constantly evolving & changing flows & loadings that arise throughout the stroke. However, their steady-state examination of the orthogonal (stalled) blade position was quite interesting. It confirmed what I already knew, what some have found by experiment or accident & what others naively describe as "flaws in technique" - that the top few % of the blade plays no significant part in the loading of the blade. There is trivial pressure on the front, & none on the back of blade in that region because the fall in pressure deeper down the back face of the blade draws away the water which might otherwise (by internal tension) have provided useful pressure differential. It also showed substantial pressure drop lower down behind the blade & the beneficial effect of water being able to pass around the blade edges, top & bottom & thus, to a degree, slow down the evolution of a back face cavity. And this further confirmed the benefit resulting from rowing the blade at greater depth, such that air could nolonger entrain & get behind the blade to separate it from the surrounding water. To some of us this is what we'd expect, but in rowing as a whole the notion of rowing deep & not creating a cavity is still anathema. But those who feel that way doubtless still kid themselves that a blade works by pushing water, rather than pulling against the much larger mass of solid water which should surround its convex back. In those intervening 11 years, & even more since your days on the PDP11, Walter, the capabilities of computational fluid dynamics have much improved, following Moore's Law like so much else in computing (except maybe the declining utility of ever-bloating word processors & the general clunkiness & error proneness of programs written by accountants?). So it should by now be possible, if not to solve the entire problem (which at that time was described jokingly to me as maybe tougher than getting a man on the moon), then at least to extend way beyond the limited but useful computer-generated insights that were quite readily obtainable 11 years ago. Indeed, I am quite sure we can now make big advances by breaking the problem up into manageable chunks & running sensible computational & practical experiments on these chunks in tandem - just as I did when I cut the top inch off 1 of a pair of sculls to prove that this bit was irrelevant to the blade's performance, & had that insight confirmed by CFD. We just need to break down this wooden-headed attitude that the only way to go faster is to pull harder. And the other damaging belief that good rowing must always carry the same sensations & rhythms as those to which we became attached when we first learned to row "well". Mind you, it'd do no harm for starters for those who coach to understand that blades don't work by pushing water.... Fat chance, do I hear you say? (he was > at our Aikido club, not a rower). > Any time you learn something new, it's usually good for generating > more questions. > W -- Carl Douglas Racing Shells - Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK Find: http://tinyurl.com/2tqujf Email: carl@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682 URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers) |
| 04 May 2008 15:55:49 |
| John Mulholland |
| Re: Hurrying the recovery - Rushing into the catch |
<wmartind@gmail.com > wrote in message news:f8215b55-4f34-49c1-96ef-1dbd603a58ad@t12g2000prg.googlegroups.com... > On May 3, 12:14 pm, paul_v_sm...@hotmail.com wrote: >> On May 2, 3:00 pm, "Charles Carroll" <charles_carr...@comcast.net> >> wrote: >> <snip > > It's not so much that either of us know so little about rowing, it's >> that we both know a good deal about shooting (not that there is >> terribly much to know about ballistics, especially since the internal >> bits are kind of chaotic, we're stuck with making reasonable >> guesses.). [;o) >> <snip > > >> - Paul Smith > > Oh well. Just to P-O some tree huggers - we were out about 10 days > ago and got 16 possoms near Pyes Pa. We could only collect about 10 > of them because the others fell into some pretty rugged country or > behind deer fences. $120NZ for a kg of possom hair - that's about 15 > animals.. Blended with Merino wool, it's probably the warmest and > softest garment you'll find. Apparently the fellows thought I was a > pretty decent shot and want to do this again. (for the non-Kiwis in > this NG, the possom is to New Zealand's vegetation almost what the > bubonic plague flea was to European people, way back when, so if you > kill LOTS of possoms, you're a good Kiwi). > <snip > > W With the way this thread is heading, perhaps it should now be titled "shooting the slide"? -- John Mulholland |
| 04 May 2008 12:03:35 |
| Re: Hurrying the recovery - Rushing into the catch |
On May 5, 2:06 am, Carl Douglas <c...@carldouglas.co.uk > wrote: > > Wasn't the possum foolishly imported from that bigger island over to > your left? Just like the fox, rabbit, sheep - & the white man - whom > the Brits thought it'd be clever to send there. And, of course, rats > went everywhere that sailors ventured. Not to mention the grey squirrel > brought to England from N America, & the mink, & the ever growing flocks > of green parakeets (from Oz) that infest this locality. Perhaps a bit > more tree-hugging at the right time, a bit more forethought on the > likely influence of imported species? Nah! We don't do that kind of > thinking! And no amount of artillery will reverse the irreversible. > > Um... If fox were imported to NZ I think it was only short-lived. Yes, the possum were brought in from the West Island. Apparently you're not allowed shoot them there, but here they're considered a true pest. W |
| 04 May 2008 21:12:45 |
| Carl Douglas |
| Re: Hurrying the recovery - Rushing into the catch |
wmartind@gmail.com wrote: > On May 5, 2:06 am, Carl Douglas <c...@carldouglas.co.uk> wrote: > > >>Wasn't the possum foolishly imported from that bigger island over to >>your left? Just like the fox, rabbit, sheep - & the white man - whom >>the Brits thought it'd be clever to send there. And, of course, rats >>went everywhere that sailors ventured. Not to mention the grey squirrel >>brought to England from N America, & the mink, & the ever growing flocks >>of green parakeets (from Oz) that infest this locality. Perhaps a bit >>more tree-hugging at the right time, a bit more forethought on the >>likely influence of imported species? Nah! We don't do that kind of >>thinking! And no amount of artillery will reverse the irreversible. >> >> > > Um... If fox were imported to NZ I think it was only short-lived. No, I didn't say they were. By there I was referring to Oz - but I admit it could have been better put. AIUI you don't get what Wilde called "The unspeakable in pursuit of the uneatable" in the land of the long cloud > Yes, the possum were brought in from the West Island. Apparently > you're not allowed shoot them there, but here they're considered a > true pest. No top predator to keep 'em down, except those who sprinkle shot around the place. Does possum make good eating, or just a sitting (if marsupial) duck? By the bye - what about the rowing questions? Cheers - Carl -- Carl Douglas Racing Shells - Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK Find: http://tinyurl.com/2tqujf Email: carl@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682 URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers) |
| 04 May 2008 17:55:35 |
| Re: Hurrying the recovery - Rushing into the catch |
On May 5, 8:12 am, Carl Douglas <c...@carldouglas.co.uk > wrote: > wmart...@gmail.com wrote: > > On May 5, 2:06 am, Carl Douglas <c...@carldouglas.co.uk> wrote: > > >>Wasn't the possum foolishly imported from that bigger island over to > >>your left? Just like the fox, rabbit, sheep - & the white man - whom > >>the Brits thought it'd be clever to send there. And, of course, rats > >>went everywhere that sailors ventured. Not to mention the grey squirrel > >>brought to England from N America, & the mink, & the ever growing flocks > >>of green parakeets (from Oz) that infest this locality. Perhaps a bit > >>more tree-hugging at the right time, a bit more forethought on the > >>likely influence of imported species? Nah! We don't do that kind of > >>thinking! And no amount of artillery will reverse the irreversible. > > > Um... If fox were imported to NZ I think it was only short-lived. > > No, I didn't say they were. By there I was referring to Oz - but I > admit it could have been better put. AIUI you don't get what Wilde > called "The unspeakable in pursuit of the uneatable" in the land of the > long cloud > > > Yes, the possum were brought in from the West Island. Apparently > > you're not allowed shoot them there, but here they're considered a > > true pest. > > No top predator to keep 'em down, except those who sprinkle shot around > the place. Does possum make good eating, or just a sitting (if > marsupial) duck? > > By |