alluminum boats and pour in foam. explain this to me.

[tincanman]

I'm farly new to this forum. what a great database of info and some great people.

I have only owned fiberglass boats, but looking into getting into alluminum boats as most of my boating will be inland lakes now. been preparing for a reso, and reading up on all these great tin boat threads. My question is, why do some of you use pour in foam in these builds? From what I can tell, these tin boats are not made to keep water above deck like a sealed deck fiberglass boat(which we all know doesn't keep all water above deck anyway) Even the best closed cell foam will absorb water, and fairly fast if the deck is just letting water go down around the edges. Can someone explain this to me?

If this has been covered, I apologize, havnt found the thread yet.

 

[carpedium]

Re: alluminum boats and pour in foam. explain this to me.

It has been covered in parts in many threads, but you would need to spend an hour perusing to find it i think.

Here are the main reasons:

- Pour in foam these days are supposedly tougher and will not soak water in as quickly
- It acts as a sounds and vibration deadener
- It conforms to fit the most flotation in a given area vs. noodles, etc.
- "If its good for the OEM, its good enough for me"

That said, I went with Extruded polystyrene boards based on never have to worry about soaking up water, I got enough buoyancy, its less expensive, not as messy, and it allows for channels for bilge drainage.

 

[64osby]

Re: alluminum boats and pour in foam. explain this to me.

That said, I went with Extruded polystyrene boards based on never have to worry about soaking up water, I got enough buoyancy, its less expensive, not as messy, and it allows for channels for bilge drainage.

Nice answer Carp, +1 on not using poured in foam.

 

[djpeters]

Re: alluminum boats and pour in foam. explain this to me.

some of you use pour in foam in these builds?

"Some" could only mean me. LOL.

I put it back in because of ALL the reasons carpedium mentioned. Pool noodles have a hole in them and because they are round you lose roughly 1/3 of the possible flotation because of the shape. Some others have questioned how long they will last as well. I didn't go foam board because I didn't want to risk squeaks and it would seem time consuming cutting it all up to get it to fit just right. No one can prove they have enough flotation when using noodles. The common answer is "I think it's enough". To me I poured in x amount of foam in which equals a specific amount of flotation. In my particular case I have almost twice what I would need. I did this even after spending the better part of a month digging out the old, and after 32 years only a very very small amount was wet. My original deck was damp all the way through, but the foam directly under it was dry. My .02c.

 

[carpedium]

Re: alluminum boats and pour in foam. explain this to me.

In fairness to Dave, I would have thought harder about going back in with pour-in foam if my experience was not this:

As a point of fact, calculating the buoyancy of foam board or noodles is fairly easy. Basically it = (volume of foam * weight of water) - weight of foam.

 

[kfa4303]

Re: alluminum boats and pour in foam. explain this to me.

The pour in foam also serves a structural purpose on many boats that have it installed from the factory. Many people will still choose to remove and replace the factory foam using pink/blue foam board, or other methods as described, but they will also have to add some bracing in the form of aluminum angle to make up for the lack of structural integrity that comes about as a result of removing the factory foam. Regardless of the type of closed cell foam you use, make sure you use enough. I believe the rule of thumb is that 1 cu.ft. of pink/blue insulation board will float approx. 60 lbs. of weight and 1 pool noodle will float about 100 lbs. Make sure you factor in your weight and that of your passengers, along with the weight of the motor and all your gear when trying to determine how much foam to add.

 

[jasoutside]

Re: alluminum boats and pour in foam. explain this to me.

Foam talk!!!!

Yah, you pretty well have it there tin man.

I love pour in....


....now, if only it had some sort of drainage. Rats. Back to alternative methods.

 

[jigngrub]

Re: alluminum boats and pour in foam. explain this to me.

Read this from the USComposites site:

Common Applications: Our 2LB density marine foam is recommended for void filling in nonstructural applications. This product can be poured underneath decks and inside cavities where a lightweight flotation foam is needed to provide buoyancy. This foam has been tested in accordance with U.S. Coast Guard Regulation # 33 CFR 183.114 . This foam is approximately 95-98% closed cell which resists absorbing water, however continuous water submersion can eventually lead to loss of buoyancy over a period of years. We recommend this product strictly for flotation applications. If looking for a liquid foam for sculpting or casting we recommend using at minimum our 3LB or 4LB density. More questions?

It takes a long time of neglect (that's right, neglect) for today's 2 part foam to become waterlogged. If you maintain your boat properly your foam won't waterlog. This could be as simple as raising the bow up as high as your jack will go while the boat is on the trailer and remove the bilge plug. Even better is to keep your boat covered with the bow up and the plug pulled. the best is to keep it garaged.

I have a '97 Tracker with the original foam that is bone dry because I keep my boat covered and the plug pulled. Covering your boat also prevents UV damage when it's stored outside all the time like mine is.

Pool noodles aren't as long lived as the sheet foam and sheet can rattle around in the bilge if not secured.

If I ever have to install foam in a boat I will use the expanding foam and the sheet foam. I'll secure the sheet foam using the expanding foam as an adhesive and fill the smaller voids with the expanding foam

 

[64osby]

Re: alluminum boats and pour in foam. explain this to me.

Back to alternative methods.

I'm just wondering if you remembered to glue the caps on.

 

[jasoutside]

Re: alluminum boats and pour in foam. explain this to me.

Why, you aren't going to sneak under there and try to unscrew em are ya!!!!!

Darn kids these days...

 

[64osby]

Re: alluminum boats and pour in foam. explain this to me.

I have enough stuff to mess with on my boats. lol

 

[Captain Shikaboo]

Re: alluminum boats and pour in foam. explain this to me.

I don't know why, but that reminds me of Easter...

 

[tincanman]

Re: alluminum boats and pour in foam. explain this to me.

"Some" could only mean me. LOL

.

Well djpeters, I will freely admit that yours one one of them, but not the only one I have found. When I grow up, The 22' ss is the boat I wan't to own. Or when I can find one of the damn things with an outboard.

And wow on the soda bottles and such on flotation. do you guys use discarded alluminum cans to repair the hull? lol

 

[tincanman]

Re: alluminum boats and pour in foam. explain this to me.

Oh, and I would be an advocate of pour in foam If someone could prove to me that I wouldn't be scraping that stuff out in 5 years when my tin boat gained a few hundred pounds. No rattles, and sound deadening would be a nice addition.

 

[jasoutside]

Re: alluminum boats and pour in foam. explain this to me.

do you guys use discarded alluminum cans to repair the hull? lol

I know right? Next thing ya know some fella will put an alum ladder in for structure that should have been trashed at the curb. Embarrassing really:facepalm:

 

[djpeters]

Re: alluminum boats and pour in foam. explain this to me.

Those under deck pics of Jas' keep popping up all over the forum! LOL

A little wet foam in 32 years isn't going to worry me, but I feel good about the amount of flotation I have and the sound deadening it will provide to my hull. It might even add a little stiffness to the deck.

FWIW, I tried laying in sheet foam on the ribs first and then pouring the foam on top to try to leave a gap between the hull and foam, but that was pointless. When you pour the foam from the bucket, it's really runny, almost as thin as water. It will creep EVERYWHERE. After the first try I adopted the thought of "If it's good enough for the factory, it's good enough for me", and just poured it in, piece of cake!

Surprised the "Saltwater trapped in the hull" statement hasn't come up yet. My boat never saw salt and won't while I own it.

 

[carpedium]

Re: alluminum boats and pour in foam. explain this to me.

What mine ended up looking like:

The saltwater point is a good one as well. I do plan to dunk my boat in the brine once or twice.

 

[jigngrub]

Re: alluminum boats and pour in foam. explain this to me.

I don't know why, but that reminds me of Easter...

Looks like tsunami debris to me.

 

[kfa4303]

Re: alluminum boats and pour in foam. explain this to me.

I'm just wondering if you remembered to glue the caps on.

Awesome, economical, ecological, colorful, DIY and super safe and functional! Shoot you could even take out the foam if/when you have to make a repair, then just put it right back in. Perfecto! Not only is the boat itself recyclable, but so is the floatation. Tinny Power!

 

[jasoutside]

Re: alluminum boats and pour in foam. explain this to me.

Looks like tsunami debris to me.

Tsunami with a hint of "Mountain Fresh Scent"