to foam or not to foam

[Cutlass18]

I've got an old 18' speedboat that we're replacing stringers, sole and hopefully not transom on. The boat's got no foam beneath the sole, and I'm debating adding a two part mix to fill the space between the stringers. Is this going to throw off my buoyancy and mess with the boat in ways I don't wanna deal with?

 

[harleyman1975]

just adding about 20 pounds and flotation. use the correct product. closed cell.

 

[GA_Boater]

Welcome to iboats.

Foam doesn't affect buoyancy. You can fill a boat from gunnel to gunnel and it won't change how it floats. It may settle a wee little bit deeper in the water from the added weight of the foam, which is minuscule.

What boat are you working on?

 

[jbcurt00]

............................. I'm debating adding a two part mix to fill the space between the stringers. Is this going to throw off my buoyancy and mess with the boat in ways I don't wanna deal with?

Use 2lb pour in foam, unless you overfill the space below deck and deform the hull, then no, it won't mess w/ the boat or it's buoyancy.....

 

[DeepBlue2010]

What year/make and model is your boat? And where are you located? If it is 18 foot, and assuming you are in USA, it was supposed to have foam right out of the factory but I am blanking on the year this regulation was implemented.

In any case, I dont expect it to mess with your boat any more than a child weight would. Floation foam is one of the best and cheapest insurance you can have for your boat specially if you take into account that if your boat sinks - G forbid - you are responsible for all the fees to retrieve it from the bottom and all the fees to clean up fuel and oil. At least in US you are

 

[Corjen1]

check this out....

http://forums.iboats.com/forum/boat...u-who-ask-about-flotation-foam-is-it-worth-it

 

[Cutlass18]

Its a Pacific Mariner Cutlass, built in La Conner, WA, in what must be the early 60s. I'm in the Seattle area. We've never been able to pin down a year on the boat. I've had it for a dozen years. we did a half assed stringer and floor repair a bunch of years ago, but I was in high school and stupid and did a crappy job at it. I'm gearing up to get going on the project in the next few weeks here.

 

[82rude]

Like the looks of the oldie.A good buff and wax would make her look great.

 

[Cutlass18]

I got her from a friend who's neighbor bought the boat new. He remembers it as a 1954, but I have no way of confirming if she's actually that old. This weekend she gets cleaned up inside and out, and the engine run for the first time in about a year and a half.

 

[NAT1VE]

Foam it.

 

[sphelps]

Very nice old runabout ! http://www.fiberglassics.com/library/Pacific_Mariner
I would put some kind of flotation ... Just make sure it's closed cell .... The pink or blue sheet foam you get from the hardware stores will work also ... Just cut it to fit between the stringers before the deck goes down ...

 

[mickyryan]

foam is better then no foam , would hate to lose this beauty

 

[bob johnson]

is that 2 part 2lb foam the same thing the manufacturers use?????? I just pulled the foam out of my Lowe....it was blown in as two part... and it absorbed 15 lbs of water per cubic foot!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! what a disaster!

I just cut the fuel tank out of a 1996 Bayliner capri 19.5 footer.... its foam was Totally saturated as well..........

that stuff is horrible

bob

 

[DeepBlue2010]

Bob, The way I see it, foam is a tool designed for certain purpose; misuse it and you will get hurt. Closed cell foam will absorb water if exposed to it for any significant length of time. Keeping the boat will drained and ventilated with the bow raised up in storage and covered during rain season would help great deal keeping the boat/foam dry.

I personally uses Oops method of wrapping the foam in shrink bags but I don't expect everyone to go to this extent.

 

[mickyryan]

thing about foam , it don't store water if water has someplace to evacuate so drilling homes into each compartment will allow air to breath and remove the water by evaporation or dripping out, if left wet all the time , I can see the reason someone would think its bad but if water has a place to go the foam will release it as does a sponge when left sitting to dry ..
best example I can use is stick a sponge in Tupperware, wet leave for a week, see all the condensation inside , now drill a small hole in the Tupperware and recheck 2 weeks later, I bet water is gone and sponge is dry , same thing with boats.

 

[gm280]

thing about foam , it don't store water if water has someplace to evacuate so drilling homes into each compartment will allow air to breath and remove the water by evaporation or dripping out, if left wet all the time , I can see the reason someone would think its bad but if water has a place to go the foam will release it as does a sponge when left sitting to dry ..
best example I can use is stick a sponge in Tupperware, wet leave for a week, see all the condensation inside , now drill a small hole in the Tupperware and recheck 2 weeks later, I bet water is gone and sponge is dry , same thing with boats.

Not contradicting your premise, but merely making some statements for thought. If there is any place that water can pool it will. Even with drilling holes will allow water in as well as water out. But the hole placement would be critical. I thought over this exact same dilemma on my rebuild boat project for a long time. I thought and thought about how to allow water to get out of any compartment. And everything i could think of also allowed water to get in. So I went with sealing up all those compartments instead of drilling any holes to drain. So everybody has to think about their own project and do what they think is best for them. In my opinion, there is no one way or only way to do such things. To each their own. If you think drilling holes is the better idea, go for it. If you think sealed compartments is the better idea, then do that as well. Personal choice. And for the record I can easily see both side of this. JMHO

 

[GA_Boater]

thing about foam , it don't store water if water has someplace to evacuate so drilling homes into each compartment will allow air to breath and remove the water by evaporation or dripping out, if left wet all the time , I can see the reason someone would think its bad but if water has a place to go the foam will release it as does a sponge when left sitting to dry ..
best example I can use is stick a sponge in Tupperware, wet leave for a week, see all the condensation inside , now drill a small hole in the Tupperware and recheck 2 weeks later, I bet water is gone and sponge is dry , same thing with boats.

The sponge is open cell or it would never absorb water. 2 part foam is closed cell, so it doesn't absorb water.

But add freezing temps to the mix to wet 2 part and all the nice closed cell foam becomes open cell and absorbs water. The longer it goes through freeze cycles, the more water it absorbs.

I know that doesn't account for Southern boats, but maybe constant exposure to water also causes the breakdown.

 

[bob johnson]

well if your boat is a garage queen!! sure it might just last a lot longer.... but if you motor out on the salt, it can get rough and there is NO keeping water out of the boat!....and once there...it is TRAPPED......is it the duty of every boat owner to tear up his welded or riveted or fiberglassed in floor to look for ways to drain water!!!!!!!! heck no!..... Lowe designed my boat there are 1" wide channles crimped in the hull material to add stiffness.. and this alone would allow water to run to the bilge...all by itself....but Lowe went ahead and blew expanding foam into all the spaces under the floor and that foam totally filled those channels.... I had to drill out all those passages and blast it with a powerful power washer.....to remove that foam!!........to me it is just a cost cutting feature....expanding foam.... they could cut each piece and insert them like I am doing now..... but they wouldn't.....

bob

 

[bob johnson]

each one of those spaces was holding 15 lbs of water...I weighed them!

look at those perfectly places channels.....now they drain water.....I cut and places solid 2" wide foam in ach space and the water runs to the back underneath the foam now...


bob

 

[gm280]

each one of those spaces was holding 15 lbs of water...I weighed them!

look at those perfectly places channels.....now they drain water.....I cut and places solid 2" wide foam in ach space and the water runs to the back underneath the foam now...


bob

That is a good idea for YOUR boat. Bu not all boats are built that way. So that is why each person have to evaluate which way they want to go when thinking about foaming or not foaming. A lot of folks have contemplated this exact situation and I believe many of them still wonder if they chose the best option for their rebuild.
Like I previously stated, there is no right way or wrong way. Only what the owner ways to do. JMHO