RE: Bow Bouyancy w/ styrofoam

From: Ken Preston (preston@gencc.com)
Date: Wed Apr 05 2000 - 10:19:20 PDT


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I think I'm right with you except that you refer to the hatch and the cabin
door and the gunnels as if they were the limiting factors. I think in each
case the larger issue is the centerboard trunk top slot. If you're trying
to blow air into your turtled problem can't it freely excape out said slot?
If you're swamped I'm positive the slot is quite a lot lower than the hatch
or the gunnels, and not terribly blockable (though I'd try I'm sure). I
liked Robert Manry's modification to his "Tinkerbelle". . .converted from a
centerboard to a daggerboard that ran in a trunk extending all the way from
the bottom of the boat plum through the cabin top. . .the British do that in
a number of boats one way or another and it does seem "seamanlike" to me. I
doubt I'd ever try such a thing on my P-15, I like the ability to hoist the
board as I bump toward the beach so easily, but an enclosed CB trunk and an
alternative method of hoisting the CB seems like something well worth while.

For an extended cruise I'd be interested in putting essentially everything
into river raft type waterproof bags and securing it all to the sides/bottom
of the boat with straps. Other than that, the buoyancy bags under the
cockpit seats would be grand. . .

-----Original Message-----
From: Jim Nolan [mailto:panache426@hotmail.com]
Sent: Wednesday, April 05, 2000 8:55 AM
To: wwpotter@tscnet.com
Subject: Re: Bow Bouyancy w/ styrofoam

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Robert:
The question is - what is the purpose of the flotation? The stock foam that
was in my P-15 did the job of keeping the boat afloat when fully swamped.
Adding 100 lbs of flotation will displace about 14 gallons of water in a
swamped boat. A swamped P-15 holds roughly 500+ gallons of water or 3500 lbs

of water.
If your intent is to make the P-15 self rescuable in the event of a swamping

I would recommend filling every bit of unused space with some type of
flotation. This is to get the gunwales above the water to be able to bail
the boat out. Otherwise you have an unrecoverable boat that sits slightly
higher in the water. If it floats with the nose down - great! you can pump
it out as long as the hatch isn't under water. I don't think flotation on
the cabin roof is practical, as that part is the only part that sticks out
of the water when the boat is swamped.
Annapolis Performance Sailing offers some nice flotation bags at reasonable
prices. They are perfect for under the cockpit which is mostly unused space
and where the water goes when you swamp it. It's also the hardest place to
remove water from. You have to get the water out of there to get your boat
back on the trailer. Check the winch and trailer capacity and figure how
many gallons of water in your boat will make you exceed it.
The best way to see this for yourself is to get some brave volunteer to
swamp his P-15 in about 5-6 feet of calm water and find out how it floats
and what it takes to get the thing out of the water. Then you'll have some
idea of what is involved when you are a few miles offshore, alone with big
waves.
One thing I haven't considered in much detail, but is ripe for discussion,
is to take a swamped P-15, turn it turtle and then blow air up under the
boat into the cabin with the door on. This will displace water and it may
float higher when un-turtled.

Jim Nolan ex P-15; P-19 #426 Panache; Colorado (temperature today in
60-70's, 4 feet of snow on ground, wind gusts 100+ mph)

>From: Robert Skinner <robert@140.com>
>To: HandyM2@aol.com
>CC: wwpotter@tscnet.com
>Subject: Re: Bow Bouyancy w/ styrofoam
>Date: Wed, 05 Apr 2000 09:51:30 -0400
>
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> West Wight Potter Mailing List maintainer
> dfarrell@ridgecrest.ca.us
> List hosted by www.tscnet.com
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>HandyM2@aol.com wrote:
> > << Another approach to bow buoyancy -- 1" styrofoam secured on top of
>the
> > cabin floor/bunks would provide about 100 lbs of floatation. >>
> > Why not go for closed cell foam padding? Softer to the humans and will
>not
> > crumble under the loading of feet and bodys upon it.
>
>Michael -
>
>The closed cell flex foam is an interesting idea. I could cement it
>to the top of some floorboards I plan to put in. On the other hand,
>as I will be stowing gear in 1/2 of the cabin and sleeping in the
>other, and stowing some gear in the sleeping area during the day, I
>wonder how the foam would stand up -- let alone stay clean enuf to be
>pleasant.
>
>Little Dipper has a fiberglass cabin floor. It is so weak in places
>that I hesitate to step or kneel on it. Therefore, I am covering it
>with 1/2" plywood, secured to the existing floor where it is strong
>enough to hold screws. The foam could go between the fiberglass and
>the plywood.
>
>Re. the already low headroom in the cabin: As I cannot sit up or
>squat in the cabin now, not much loss...
>
>With the noodles below the floor and the foam in the sandwich, I would
>have 80 + 100 lbs of floatation. The key question is -- is this
>overkill?
>
>Any comments will be appreciated.
>--
>Robert Skinner, Rockville, Maryland
>'87 Potter 15 HMS #1618 "Little Dipper"
>

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