Re: [Paddlewise] Bulkhead Pressure Relief

On 20 Jul 2003 at 10:55, Seakayakerjb_at_aol.com wrote:

> What's the experience with leakage from cockpit into "dry"
> compartment?

Minimal leakage.  If I'm doing lots of rolling and rescue practice, 
the rear compartment gets maybe a tablespoon of water in it.  The 
forward compartment gets less.  With normal paddling, things stay 
bone dry.

> What size hole was drilled?

The smallest bit in the set - 1/16 inch.

> Where was hole positioned--top-center; middle-center; etc?

As close to the geometric centre of the bulkhead as I could guess by 
eye.  That way, the hole is furthest from the water regardless of the 
orientation of the kayak.

> Finally, if leakage is a problem, I would cover the hole (small hole)
> with a piece of Gore-tex on the wet side to allow pressue to pass, but
> not water  (electronics manufacturers use this technique--seems to
> make sense here too).

I thought of that, but have never got around to it.  Leakage hasn't 
been enough to worry me.  I've never been able to figure out if the 
GoreTex would breath fast enough to handle pressure changes.  The 
electronics devices (like my GPS) don't have a lot of volume to deal 
with compared to a kayak.  Taking a hot kayak and dropping it into 
cold water used to cause the hatch covers to suck in very noticibly 
before I drilled the holes.  That's several cubic inches of air in a 
short time.

You could also use a bit of tightly woven cotton and rely on the 
cotton swelling when wet to reduce water intrusion.   If the 
compartment heats, the cotton will breath easily.  If it cools, the 
wet cotton will likely allow a bit of water to be sucked in, but 
nothing serious.

Mike

***************************************************************************
PaddleWise Paddling Mailing List - Any opinions or suggestions expressed
here are solely those of the writer(s). You must assume the entire
responsibility for reliance upon them. All postings copyright the author.
Submissions:     PaddleWise_at_PaddleWise.net
Subscriptions:   PaddleWise-request_at_PaddleWise.net
Website:         http://www.paddlewise.net/
***************************************************************************