What and where to foam

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BB Sig
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Re: What and where to foam

Post by BB Sig » Sat May 19, 2018 9:38 pm

Jaysen wrote:
Sat May 19, 2018 8:05 pm
Maybe my experience is abnormal though.
When is it not?! :lol:

I vote foam. You got me thinking about what to do for my GT. I like the idea of foam under the gunwales. I could do it behind the seat backs. It would serve to float the boat up right but also stiffen the sides.



OrangeQuest

Re: What and where to foam

Post by OrangeQuest » Sat May 19, 2018 9:48 pm

For most boats to roll there would have to be more weight towards the upper part of the boat than the bottom. The wood in most wooden boats float which would aid in the boat staying up right. One thing about floatation in the bottom of the boat is it displaces the water. major leak water comes into the hull till the boat reaches neutral buoyance then the water stops coming in. Maximum floatation is below the surface so maximum help at keeping the boat at the surface. If most the floatation is in the upper parts of the boat then it doesn't help with any of that till more of the boat is under water. Most the time a boat rolls because the people are putting their weight on the side of the boat or a wave rolled it.

People wear a life jacket loosely and if they fall in the water the jacket floats high out of the water but the person in it is not. When they tighten the jacket down more of them is out of the water but more of their jacket is under water so more lift.

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cape man
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Re: What and where to foam

Post by cape man » Sun May 20, 2018 7:24 am

My dory has 13 separate compartments below the sole, each fully sealed and taped, and full of 2 part poured foam, sold here. The sole is sealed and taped to the sides and covered with glass. The only penetrations are the screws to hold the fuel tank and leaning post, and they are all drilled oversized, filled with epoxy, and predrilled. If I ever penetrate the bottom, the only water will be what can fill any void around the foam in that compartment, which will be measured in ounces.

I spent extra time and materials sealing each compartment, paying special attention to the chase tubes.

While indeed, shit happens, I am VERY confident there is no way for water to get below my sole without a major incident puncturing the bottom or the deck. Part of building the boat was to consider all this and make sure to do it right, as prescribed here.

The assertion that water will inevitably get in doesn't apply to my boat, or most others built here, and built right.

As to turning turtle if fully swamped, I hope we never learn that answer for an OD18, especially mine. I have no plans to ever be somewhere where that might even remotely happen.
The world always seems brighter when you've just made something that wasn't there before - Neil Gaiman

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Re: What and where to foam

Post by Capt UB » Sun May 20, 2018 9:02 am

Fuzz wrote:
Wed May 16, 2018 6:24 pm
There is a lot of debate going on now and in the past so I thought I would start this thread to get folks input.

Lots of folks foam in the whole bottom. Some want no foam below the water line and limber holes for draining. Both have their good and bad points. So what are you guys doing and why?

I follow the TO foam group... I have owned 3 CC Scout SportFish (141, 145, 155) all were foam filled. The foam was/is part of the strength of the hull and deck. As for water soaked foam, never had that problem with them, they all were over 10 years old. BUT what I did have was water trapped in the hull.

On my FS14, I epoxied the stringers and floor frames very well. Any pumbing/electrical pipes (pvc) holes were sealed with 5200. I glassed the sole to the hull and bulkheads.

If I were to foam a compartment I would epoxy the all sides and use heavy duty lawn and garden bags inside the compartment (fill them up with foam).

The lower the foam is, the higher the boat will rise out of the water... If you get swamped, but are upright, you could still use your motor (right amount of foam) and bilge pump and a bucket will save you...

Never had a way to stay afloat on my Offshore sailboats! Lots of ways to stop water from coming in.....

I think if you use foam, bag it.....
FS14 (SandPiper) launched 10/20/2018

LM18 Starting build in November 2018

OrangeQuest

Re: What and where to foam

Post by OrangeQuest » Mon May 21, 2018 7:26 pm

Here is a picture of what I was talking about the flotation being high and the whole boat has to go under before floating. Here is a kayak that became swamped from a wave. You can see were the blue behind me is the boat and my PFD is the only flotation. Disregard the fact the boat is sitting on the bottom. :lol:
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Re: What and where to foam

Post by Fuzz » Tue May 22, 2018 2:22 am

cape man wrote:
Sun May 20, 2018 7:24 am
My dory has 13 separate compartments below the sole, each fully sealed and taped, and full of 2 part poured foam, sold here. The sole is sealed and taped to the sides and covered with glass. The only penetrations are the screws to hold the fuel tank and leaning post, and they are all drilled oversized, filled with epoxy, and predrilled. If I ever penetrate the bottom, the only water will be what can fill any void around the foam in that compartment, which will be measured in ounces.

I spent extra time and materials sealing each compartment, paying special attention to the chase tubes.

While indeed, shit happens, I am VERY confident there is no way for water to get below my sole without a major incident puncturing the bottom or the deck. Part of building the boat was to consider all this and make sure to do it right, as prescribed here.

The assertion that water will inevitably get in doesn't apply to my boat, or most others built here, and built right.

As to turning turtle if fully swamped, I hope we never learn that answer for an OD18, especially mine. I have no plans to ever be somewhere where that might even remotely happen.
I know at least one beach where WE might be able to put this to the test :wink:

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Re: Level Flotation

Post by Magnetic4 » Wed Aug 08, 2018 4:49 pm

I just purchased plans for a C19 based on description that boat could be provided with Level Flotation as required by USCG.
Unfortunately absolutely no information on how to achieve this on the plans.
The minimal foam flotation indicated on plans between stringers is inadequate in my opinion.
Looked up the USCG info and fairly obvious that Level Flotation calculation should be undertaken by the designer.
Has anybody any information on how to make a C19 comply with the USCG Level Flotation requirements ?
Is there a supplementary shhet of plans available ?

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Re: What and where to foam

Post by Jaysen » Wed Aug 08, 2018 4:54 pm

Keep in mind that USCG regs aren’t applicable in all cases. There are different regs for commercially built vessels and home built.

Not saying it isn’t a good idea. Just may not be needed

OrangeQuest

Re: Level Flotation

Post by OrangeQuest » Wed Aug 08, 2018 5:53 pm

Magnetic4 wrote:
Wed Aug 08, 2018 4:49 pm
I just purchased plans for a C19 based on description that boat could be provided with Level Flotation as required by USCG.
Unfortunately absolutely no information on how to achieve this on the plans.
The minimal foam flotation indicated on plans between stringers is inadequate in my opinion.
Looked up the USCG info and fairly obvious that Level Flotation calculation should be undertaken by the designer.
Has anybody any information on how to make a C19 comply with the USCG Level Flotation requirements ?
Is there a supplementary shhet of plans available ?
What does your boat weight before you build it?

narfi
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Re: What and where to foam

Post by narfi » Wed Aug 08, 2018 6:15 pm

fallguy1000 wrote:
Thu May 17, 2018 12:40 am
However, my Lund aluminum fishing boat jas foam.

The foam in it is well placed and it allows for drainage and it will not hold water in it.
I have a coworker who is working on a 20ft Lund, it has seen ~10yrs of use or so.
He told me he removed 1000lbs of foam from it. Not sure if he weighted it or was just frustration talking with the 1000lbs quoted. I did pick up a piece of the foam though and it was heavy.

There are no stringers, just bulkheads every 15" or so and they are all cracked out along the sides. The boat has a lot of flex and he is trying to figure out how to stretch some more life out of it.
The seat benches along the sides seam to have been designed to give it some rigidity, but they were not well attached and are all cracked out. He has it dismantled down to about the same spot I have my fs17 built up to (Bare hull with bottom bulkheads in and no side bulkheads) and mine is much much MUCH more rigid than the Lund at this stage.

Does Lund use different types of foam? or what is the issue with it getting waterlogged? Obviously with an aluminum boat there is no chance of completely sealing it, add to that the holes through the bulkheads are 1/4" off the bottom so it would be impossible to drain it all out under normal conditions as well. He is trying to figure out how to get flotation back in without causing the same issues before beefing up some of the structure to keep the sides from flexing and the boxes from breaking out. One idea I had was heavy bags of foam under the sole instead of just layed out, perhaps the bags would keep the foam from getting soaked under normal conditions?

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