17 Feb 2006 10:04:52
Wilf Williams
r.s.r/buoyancy

Here is a dilema:
Last year I rowed the Rhein regatta, in a very old 4x+, I fitted it it
with a small plastic greenhouse like wooden structure, and we taped all
the riggers so that we had 'wings' to stop the splash coming in board.
Additionaly I bought a 12v bilge pump. During the 7 hours we used the
pump to keep the boat dry(ish) and floating. see photo's of my
greenhouse here http://www.treviris.de/albums/eurega2005

This year we have a spanking new BBG 4x+ gig. Fully buoyant, sealed
compartments under each seat, super boat. However the problem is that
each foot well will undoubtedly fill up with water, and there is no
chanel to drain back to the cox's feet, and the bilge pump.
So whilst I am happy that the new boat will not sink, I can't see how
we can empty the water from each foot well. I don't facy rowing 100 km
in waist deep water. Four bilge pumps ? Elaborate plumbing ? Anyone
have any ideas, apart from the obvious, stay at home.

Wilf



17 Feb 2006 19:28:44
Carl Douglas
Re: r.s.r/buoyancy

Wilf Williams wrote:
> Here is a dilema:
> Last year I rowed the Rhein regatta, in a very old 4x+, I fitted it it
> with a small plastic greenhouse like wooden structure, and we taped all
> the riggers so that we had 'wings' to stop the splash coming in board.
> Additionaly I bought a 12v bilge pump. During the 7 hours we used the
> pump to keep the boat dry(ish) and floating. see photo's of my
> greenhouse here http://www.treviris.de/albums/eurega2005
>
> This year we have a spanking new BBG 4x+ gig. Fully buoyant, sealed
> compartments under each seat, super boat. However the problem is that
> each foot well will undoubtedly fill up with water, and there is no
> chanel to drain back to the cox's feet, and the bilge pump.
> So whilst I am happy that the new boat will not sink, I can't see how
> we can empty the water from each foot well. I don't facy rowing 100 km
> in waist deep water. Four bilge pumps ? Elaborate plumbing ? Anyone
> have any ideas, apart from the obvious, stay at home.
>

Wilf -

You have the choice between potentially sinking in the old boat, &
potentially getting unpleasantly wet legs in the new one. You're
unlikely to die from rising damp of theh shin bones, so I suggest it's a
bit of a no-brainer.

I should note that, once you are _having_ to use a pump to stay afloat
in an under-buoyant, you are very close indeed to the sharp dividing
line between staying afloat & sinking. From the moment influx exceeds
the capacity of your pump your boat will proceed to go ever lower in
theh water &, as a result, the rate of influx will rise exponentially.
From that point there is no way back.

Pumps have a capacity measured in tens or, if you're lucky, fifties of
litres/minute. Once waves consistently overtop the gunwales of your C4,
the influx goes up into the thousands of litres/minute, against which
the contribution of your pump is irrelevant.

If, for comfort, you do carry pumps in the buoyant boat (you'll still
have water sloshing around or the pump will have nothing to suck on)
then I suppose you could run 4 separate hoses to a manifold with valves
to cut off any that are sucking dry. Actually, though, I suspect the
water will slosh from one footwell to teh next and collect largely in
one place - probably around cox.

More use in keeping water out may be, rather than having such a large
wind-jammer, to just tape thickish polythene tightly over as much of teh
open top of the boat as can be covered without inconveniencing you,
rolling up the edges where appropriate to deflect the water over the
sides instead of letting it running off into the boat - a bit of simple
origami.

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)