Message-Id: <v01510101ad93152ce4dc@[199.170.68.47]>
Date: Thu, 11 Apr 1996 15:23:00 -0500
To: baidarka@imagelan.com
From: shaysnet.com!laughing_loon@imagelan.com (Rob Macks)
Subject: Re: Frame question: aluminum vs. wood
>Into the fray go I.....
>
>> Why a skin boat is not easily fitted with bulkheads is obvious when
>> you consider the difficulty of fitting a waterproof cross-sectional wall to
>> a flexible skin when the longitudinal strength members that support this
>> skin would necessarily pierce this wall in several places. Why bulkheads
>> are useful is because they can very substantially limit the amount of water
>> that will swamp the boat after a blown sprayskirt or a swim. The less
>> water sloshing around inside your boat, the more likely you will be able to
>> successfully recover from a capsize that results in a swim. There is a
>> device sometimes used called a sea-sock which will serve many of the same
>> purposes as a set of bulkheads, but it has the drawbacks of being extremely
>> uncomfortable to wear in warm or even moderate weather and of giving
>> practically no easy stowage space there in the cockpit with you.
>> Furthermore, as it is a separate piece of gear from the boat, there is a
>> chance it will not be set up and ready for use just when it is needed. A
>> kayak that is built with waterproof bulkheads always has this safety
>> feature available.
>
>While it is true that like you, I have never seen a skin boat with truly
>waterproof bulkheads and hatches, I was sitting here mulling over your
>reply to Philip Wylie and had a thought.
>
>In my hardshell ww kayak, I have fore and aft airbags. The aft bags double
>as storage bags. Thinking on this, I wonder if it might not be possible to
>create, not truly waterproof, but rather water resistant bulkheads through
>the use of inflatable bulkheads that would rest on the frames themselves
>and blow up to the skin on each side. I can see the initial problem, and
>as yet have no solution, where the force of blowing up pushes against the
>skin on each side of the rib used, possibly raising the skin and disrupting
>the smooth flow of water. But would this be any worse than the bulge created
>by the rib proper? Stow the gear, put this inflatable bulkhead at the rib
>closest to the gear and inflate for a "snug" fit against the skin on both
>sides of the rib. By design most of the force could be put against the rib
>to hold it in place and only a little of the bulkhead pushes against the
>skin. (We KNOW the diameter of the rib, we design the bulkhead to inflate
>and push against the rib with flaps that are designed to go 1/8" past the
>diameter of the rib, for example. Also, gear or foot kicking hard against
>the center of this inflatable bulkhead could concievably break the seal
>against the skin by dislocating it from sitting squarely on the rib.
>___ ___
>| | ________ | | Fully inflated, this height is 1/16" to 1/8" past
>| | | | | | the rib
>| | | RIB | | |
>| | |______| | |
>\ \__________/ /
> \ /
> \ /
> | |
> | |
>
>I think that it might be possible, using dry suit technology, to create
>truly waterproof hatches. But I agree, the cockpit is a leak, however
>slight that can't safely be made fully watertight. But floatation bags
>and possibly some such bulkhead as I describe above could do a lot to
>prevent a flooded boat in the event of a swim or blown sprayskirt.
>
>Further, I also agree that wood has a warmth that aluminum doesn't, and
>that there are roles best suited by each, not the least of which is the
>builder's desire.
>
>Just some thoughts.
>
>Bill B.
>bblohm@hpbs1686.boi.hp.com
Listening to your ideas about creating waterproof storage, accessable
similar to hard shell boats has made me think about it and I offer the
following.
Given the differences between hard shell boat and skin on frame boats it
seems to problematic to try to do the same thing in a skin boat as a hard
shell.
Focusing on the idea which is to have water proof storage accessable from
fore and aft hatch openings, why not;
Install net bulkheads. to hold storage socks in place.
Make a storage sock out of neoprene with closable collar that would be
pulled through a hatch that had it's own neoprene spray cover.
I make my own spray skirts from neoprene I buy from John R. Sweet at (703)
468-2222. It is so easy to make spray skirts. Just cut out a shape and butt
glue the edges and back up the seams with tape. For a closure you could
make a roll and Fastex snap collar like the ones on the market.
You could make fore and aft hatches just like your cockpit, smaller of
course and seal them with a neoprene spray cover. To make a spray cover
just put neoprene over the opening rubber up and put shock cord on the
hatch combing over the neoprene. Trim excess neoprene leaving 1-1/2" flap
that will fold over the sock cord and be glued in place. The ends of the
sock cord come through a hole in the skirt to the outside edge for tension
adjustment.
Hey this sounds better the more I think about it. Remember folks I have the
patent!
Rob Macks
Laughing Loon Custom Canoes & Kayaks
http://www.shaysnet.com/~robm/