14 Mar 2005 19:25:57
Andy Nield
Roof racks and SINGLE sculls

Can you carry a single scull on just the roof bars, or do you need one of
those V bar scull rack things?

I haven't tried it yet as I don't keep the bars on the car. But I'm almost
ready to start trying some off cam races, and I'm guessing I won't be able
to use just the roof bars with the riggers still on?

I want to be able to carry the boat without taking the riggers off, but
without buying a V rack if I don't need to... what do you recommend as the
best way to carry a single on top of a car?

Thanks







14 Mar 2005 21:05:13
John Mulholland
Re: Roof racks and SINGLE sculls

It depends on the single. My Lola has strong saxboards and can be strapped
straight onto the roofbars. Some more traditional wooden boats have thin
saxboards (to keep water out, not for mounting riggers), which would be
damaged. Either way you should tie a rope from each end of the boat down to
the bumper (US: fender) to prevent the ends of the boat flexing too much on
bumps.

John Mulholland

"Andy Nield" <andy.nield@ge.com > wrote in message
news:9zlZd.246$6P4.144@newsfe2-gui.ntli.net...
> Can you carry a single scull on just the roof bars, or do you need one of
> those V bar scull rack things?
>
> I haven't tried it yet as I don't keep the bars on the car. But I'm
> almost
> ready to start trying some off cam races, and I'm guessing I won't be
> able
> to use just the roof bars with the riggers still on?
>
> I want to be able to carry the boat without taking the riggers off, but
> without buying a V rack if I don't need to... what do you recommend as the
> best way to carry a single on top of a car?
>
> Thanks
>




14 Mar 2005 22:18:09
Carl Douglas
Re: Roof racks and SINGLE sculls

John Mulholland <john.mulholland@*NO*SPAM*tiscali.co.uk > writes
>It depends on the single. My Lola has strong saxboards and can be strapped
>straight onto the roofbars. Some more traditional wooden boats have thin
>saxboards (to keep water out, not for mounting riggers), which would be
>damaged. Either way you should tie a rope from each end of the boat down to
>the bumper (US: fender) to prevent the ends of the boat flexing too much on
>bumps.
>
>John Mulholland
>

You _can_ carry a single on transverse bars, but it is never to be
recommended.

Although some saxboards can "take it", none will benefit from the
spreading loads that a firm tie-down can impose and which they were not
designed to withstand.

However, the primary objection to tying down straight onto the bars is a
human safety consideration - the safety of other road users.

Very few scullers seem to know how to tie something down so that it
cannot slip sideways (please see my explanation of how this can be done
on the 2x transport thread). And most ladder bars are rather close
together. So you have over 8 metres length of boat secured (if that is
the right word) rather dodgily with a good 4 metres of projecting boat
(at one end at least). Yet you know how much a good side-gust and make
the car move when you have a boat on top, & you know how hard you'd have
to push at roof level to move the car as suddenly. And much of that
side load is applied near the forward end of the boat.

I note John's comment re bow & stern tie-downs, but how many cars have
more than one tie-down point at either end (& that one is off-set to one
side of the car. A rope down to one point only can give no protection
against a significant amount of side-slew, & then it will apply rather
severe down-forces on the boat.

Actually, a sculling boat has in itself ample strength to resist quite
phenomenal wind loadings - much greater than those which the tie-downs
done by most scullers will resist. The prime reason for the extra
tie-down at each bumper (vertical, please, not led out to the bow!) is
to prevent the initial upwards movements which mark the onset of severe
vertical pitching which could build up to a dangerous degree - due to
the relatively poor bending stiffness of some ladder bars.

All of which is why it makes the best possible sense always to car-top
your boat on a purpose-built V-bar rack, which is immovably secured by
steel U-bolts to the transverse bars. Only if you have a vehicle with a
long roof (estate or similar), plus vee-shaped chocks for bow & stern
decks, does it make any sense not to use a V-bar rack.

Cheers -
Carl
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing low-drag Riggers/Advanced Accessories
Write: The Boathouse, Timsway, Chertsey Lane, Staines TW18 3JY, UK
Email: carl@carldouglas.co.uk Tel: +44(0)1784-456344 Fax: -466550
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)



14 Mar 2005 16:26:27
oarsman
Re: Roof racks and SINGLE sculls

I would say it depends on two things, the spacing of the roof bars, and
the type of boat. If the bars are far enough apart (on my truck they
are 9') it does not seem to be a problem. If the deck is flat, just a
some padding seems to work, if there is more shape to the deck, I will
cut a piece of wood to match the shape, and put some padding on the
wood. For short bar spacing I would either use a boat carrier, or
strap an extension ladder to the rack. On top of my Toyota Tacoma PU,
I have carried my double and 2 singles to regattas as far as 1,200
miles away without problems. My double is a Van Dusen which I must say
has the best rack system out there. No straps are required on the
boat.

If your boat has a wing rigger, there are some that would argue that
this should be removed before transporting. They claim that at speed
the rigger will put stress on the boat.


Andy Nield wrote:
> Can you carry a single scull on just the roof bars, or do you need
one of
> those V bar scull rack things?
>
> I haven't tried it yet as I don't keep the bars on the car. But I'm
almost
> ready to start trying some off cam races, and I'm guessing I won't
be able
> to use just the roof bars with the riggers still on?
>
> I want to be able to carry the boat without taking the riggers off,
but
> without buying a V rack if I don't need to... what do you recommend
as the
> best way to carry a single on top of a car?
>
> Thanks



14 Mar 2005 19:36:04
Tony Curran
Re: Roof racks and SINGLE sculls

Either way you should tie a rope from each end of the boat down to
> the bumper (US: fender) to prevent the ends of the boat flexing too much
> on bumps.

No John,

A bumper is a bumper. A fender is a wing. Got it?

Tony
Ottawa RC





15 Mar 2005 04:11:19
sue t
Re: Roof racks and SINGLE sculls

A boat rack is a good investment. I like mine for several reasons:
- my shell doesn't rattle around up top
- my shell sits at a slightly higher height than it would if it was attached
to the car roof racks only
- the deck is protected from the hard surface because it sits in a cradle

One trip we attached the roof rack to the top of our motorhome and headed
off. One day we hit wicked cross winds that resulted in all traffic slowing
to about 30 mph due to the buffeting we were all experiencing. It was just
about impossible to stand in the wind so we didn't even try to get on top
the RV to check the shell out. I fretted until we hit calmer air. No
problems though. My 1x rotated slightly in the slings, but other than that
no issues.




15 Mar 2005 07:32:32
Re: Roof racks and SINGLE sculls

I thought a fender was a Guitar.... Strange cars you must have in the
UK... [;o)



19 Mar 2005 10:29:30
Ad Brandt
Re: Roof racks and SINGLE sculls

Andy Nield wrote:
> Can you carry a single scull on just the roof bars, or do you need one of
> those V bar scull rack things?
>
> I haven't tried it yet as I don't keep the bars on the car. But I'm almost
> ready to start trying some off cam races, and I'm guessing I won't be able
> to use just the roof bars with the riggers still on?
>
> I want to be able to carry the boat without taking the riggers off, but
> without buying a V rack if I don't need to... what do you recommend as the
> best way to carry a single on top of a car?
>
> Thanks
>
>
>
>
I've seen the answers so far, but no one yet has said anything about
traansporting the boat with the riggers still on. At my club, we always
take them off. Is that unnecessary? Are the loads on the boat during
travel maybe less that that during rowing, where the riggers are loaded
by the sculls during the recover?

Ad


19 Mar 2005 04:03:32
oarsman
Re: Roof racks and SINGLE sculls

Actually,

I made a statement about riggers.

"If your boat has a wing rigger, there are some that would argue that
this should be removed before transporting. They claim that at speed
the rigger will put stress on the boat."

but maybe I should go on say a single piece wing, not the tubular
wings.

I have logged many miles carrying Hudsons with the riggers (old style)
still attached with out problem. I often see many cars at the regattas
with the rigger still attached. The drawbacks to this are that you can
only fit one boat on your rack, and there is a greater risk of
scratching you car. Becuase of the areodynamic shape of my vandusen
riggers, and ease of which they are removed, I always remove them for
transporting.



19 Mar 2005 05:15:46
oarsman
Re: Roof racks and SINGLE sculls

After reading this I realize I left out that the stress is not so much
the rigger on the boat, but the rigger applying a force to the boat
that is then transferred to the rack, thus putting undesirable stress
between the boat and the rack. Without measuring it, I am sure that
the force between the riggers and boat are much grater when rowing than
car topping. I base this on the fact that I have broken two riggers
while rowing, but never while car topping.



19 Mar 2005 13:42:58
Carl Douglas
Re: Roof racks and SINGLE sculls

oarsman <oarsman101@yahoo.com > writes
>Actually,
>
>I made a statement about riggers.
>
>"If your boat has a wing rigger, there are some that would argue that
>this should be removed before transporting. They claim that at speed
>the rigger will put stress on the boat."
>
>but maybe I should go on say a single piece wing, not the tubular
>wings.
>
>I have logged many miles carrying Hudsons with the riggers (old style)
>still attached with out problem. I often see many cars at the regattas
>with the rigger still attached. The drawbacks to this are that you can
>only fit one boat on your rack, and there is a greater risk of
>scratching you car. Becuase of the areodynamic shape of my vandusen
>riggers, and ease of which they are removed, I always remove them for
>transporting.
>

The aerodynamic drag on riggers when car-topping is trivial compared
with the loads applied when rowing, even when driven at illegally high
road speeds. A boat which can't take those loads is unfit to row.

A single-stay wing rigger with flat or aerofoil section generates
substantial lift forces (positive or negative), far exceeding the drag
forces, so you do need to ponder the hold-down stresses on a wing-rigged
boat, on the ties holding it to the rack, on the fastenings holding rack
to roof bars & on the attachment of those roof bars to the vehicle.
Having the boat nose-down on the car helps to bias those forces
downwards, but curvature of the airflow around the car, & due to passing
vehicles, may still impose upward forces, while cross-winds may generate
positive lift on one side & negative on the opposite side, imposing
rotational forces on the boat.

Removing riggers for transport does make sense by reducing overall drag
& hence car fuel consumption (although wings don't fit too well in many
cars). So it amuses me that we have this serious discussion of drag
forces on riggers when discussing car transport but not when discussing
racing performance.

Cheers -
Carl
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing low-drag Riggers/Advanced Accessories
Write: The Boathouse, Timsway, Chertsey Lane, Staines TW18 3JY, UK
Email: carl@carldouglas.co.uk Tel: +44(0)1784-456344 Fax: -466550
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)