what is foam for

[fastang00]

I am restoring a 1976 sea shark 18 ft. tri hull when I pulled out the flooring i found a lot of foam that is soaking wet. I am just wondering what the foam is for and does it need replaced? thanks for any info this is my first boat restoration im used to restoring cars.

 

[MTboatguy]

Re: what is foam for

It is used for flotation, the idea is if your boat gets swamped and starts to go down it will keep the boat above water, in some boats it is part of the structure of the boat as well. If it is wet, yes it needs to be removed and then look at your options for replacing it. Your best bet is going to be do a search about foam and start reading all about it, cause if yours is wet, I can guarantee you, it is not going to dry out,, once wet, it is always wet.

 

[seabob4]

Re: what is foam for

20' and under, it's required by the CG for flotation...on new boats. Granted, at waterlogged, it's not really helping the flotation matters much.

I'd dig it all out, and start from scratch. Builders use an isocyanate 2-part foam from BASF...

 

[Dave Taylor]

Re: what is foam for

Fastang00.......

That boat foam you see serves three purposes:

The first is what has already been said.... flotation.
The second is foam is a great insulator for noise.... holding things solid that may rattle or go bump.
The last is structural.... make a hull respond and feel better (stronger) when underway in choppy waters.

I hope this helps.

 

[H20Rat]

Re: what is foam for

Just to be clear, when people say its for floatation, they mean worst case scenario, instead of the boat sinking it will float at the surface, barely. Foam in a boat does not add floatation for normal conditions, technically your boat actually rides lower in the water because of foam. (if its waterlogged, it rides substantially lower, but even dry foam has mass.)

 

[fastang00]

Re: what is foam for

Thanks for all your responses I have been looking for foam online to replace and was wondering if Two-Component Polyurethane Foam Kits would work? It expands so it would form to the shape of the boat. Is this the best option or is there something better?

 

[ezmobee]

Re: what is foam for

It's so your boat does this:

If you get swamped instead of sinking like a stone.

 

[jigngrub]

Re: what is foam for

Thanks for all your responses I have been looking for foam online to replace and was wondering if Two-Component Polyurethane Foam Kits would work? It expands so it would form to the shape of the boat. Is this the best option or is there something better?

The 2 part urethane foam is what boat manufacturers use.

This place has good prices.

http://www.uscomposites.com/foam.html

I personally would use the 4 lb. mix, but the 2 lb. mix is USCG approved.

 

[DuckHunterJon]

Re: what is foam for

It's so your boat does this:

If you get swamped instead of sinking like a stone.

Ouch, I hope that wasn't yours EZ!

 

[ezmobee]

Re: what is foam for

Ouch, I hope that wasn't yours EZ!

LOL, nope! Someone else found that on a fishing forum. I saved it in my pictures just to answer this type of question.

 

[Silvertip]

Re: what is foam for

Not only was swamping a sad thing, whoever opted for a 40 HP motor on that boat probably wishes it had a minimum 75 or 90. Way too small for that boat on that big water. Bets he took a wave over the stern.

 

[ezmobee]

Re: what is foam for

Not only was swamping a sad thing, whoever opted for a 40 HP motor on that boat probably wishes it had a minimum 75 or 90. Way too small for that boat on that big water. Bets he took a wave over the stern.

Yes, I believe the guy had that thing out on one of the great lakes and got caught in some weather. Should of had quite a bit more motor.

 

[Thalasso]

Re: what is foam for

The guy was lucky it didn't roll. Boats with outboards become top heavy and have a tendency to roll when swamped. Did this on the St Lawerance in 97.Boat will float bow up when this happens.Bigger motor will make this happen quicker

 

[beckoning]

Re: what is foam for

I have also seen people buy thick (2", 3" ?) blueboard at Home Depot and glue it together then cut it to shape. Although expanding foam seems like a good solution, it can cause havoc with wiring channels and popping rivets and pushing flooring up if it is applied after the floor is installed.