Foam under the decking, pros and cons...

[MNHunter505]

I got a voyager 16 ft and plan to install floor decking. Other than putting foam under the deck to ensure there is foam in the boat if it capsizes, are there any other pros? Does it make the deck sturdier? If I still have the factory foam, is there a need to add more foam for reasons other than flotation?
Thanks in advance. Also, what size plywood for the deck?

 

[sixgun86]

See if you Factory foam has become water logged. Also marine closed cell foam is expensive. Some use Pool noodles which I know sounds ridiculous but they work! Foam could make your decking/etc more sturdy, not noodles though.. In regards to the deck, thicker the better but if you have ample bracing it could be unnecessary. Just don't use treated.

+ Boat won't sink. Hopefully.

- Will cost $$

 

[bluegillfisher]

will add support under thinner plywood. Quiets the dropping of tackle boxes. I have pink house foam under my aluminum deck. The PO used 5/8 PT plywood with beautiful astro turf as floor. The panels lifted out to clean leaves out. Guess it's all up to you and how you are going to use boat.

 

[PSG-1]

It's definitely a good thing, for numerous reasons. Flotation, first and foremost.

It provides rigidity for thin sheet aluminum floors, dampens vibration and makes for a smoother ride.

 

[Buddychrist]

Why don't we make open cell spray in foam in a vacuum seal bag, technically it would be closed cell for extra flotation.

Just thinking outside of the box

 

[PSG-1]

Too much chance of a hole being punched in a bag from vibration and jarring, and once that happens, water infiltrates the foam, and then you've got blocks of heavy, juicy foam in your boat.....you'd be better off with concrete blocks.

So, it's best to stay with closed-cell foam.

 

[Buddychrist]

Too much chance of a hole being punched in a bag from vibration and jarring, and once that happens, water infiltrates the foam, and then you've got blocks of heavy, juicy foam in your boat.....you'd be better off with concrete blocks.

So, it's best to stay with closed-cell foam.

You haven't seen my vacuum sealer bags! I'm using a 1/2 horse industrial vacuum sealer and the bags it uses
are extremely thick. I'll post a photo of my vac sealer, when you turn it on the lights in the house dim and it sounds like a small car

 

[acabtp]

You haven't seen my vacuum sealer bags! I'm using a 1/2 horse industrial vacuum sealer and the bags it uses
are extremely thick. I'll post a photo of my vac sealer, when you turn it on the lights in the house dim and it sounds like a small car

no matter how thick a bag, i wouldn't trust it against the effects of vibration and time... even if it's extremely thick it still only takes one puncture for it to be ruined. you can poke all sorts of holes in closed cell foam and it will still won't absorb water.

 

[bassboy1]

You haven't seen my vacuum sealer bags! I'm using a 1/2 horse industrial vacuum sealer and the bags it uses
are extremely thick. I'll post a photo of my vac sealer, when you turn it on the lights in the house dim and it sounds like a small car

Why bother with the foam, in that case? Bags of air would actually provide better flotation, as they wouldn't have the weight of the foam counteracting them. I'm not a big proponent of foam (there are better options for water displacement, which is all that is desired) in aluminum boats, but I'm also not real thrilled with the idea of plastic bags providing safe flotation.

Foam does have the benefit of sound deadening and deck support, however it also is a major cause of corrosion when placed or poured up against aluminum. The important thing to do with foam would be to pour it in blocks, sealed in plastic (you are using the plastic to protect the aluminum, not to protect the foam from water), furred up from the hull with 1/2" plastic of some sort. This allows bilge water to flow where it needs to, and grants the aluminum the airflow that it needs to maintain the correct oxidation level, and as such, remain chemically stable.

 

[Buddychrist]

The reason I say bagging the foam instead of just using bags of air is that there needs to be weight somewhere otherwise how are you planning on keeping airbags held in on an open deck Jon?

Personally I am not planning on installing any more foam in my boat. I would go with closed cell foam if i was going to do it at all but I was just thinking outside of the box

 

[PSG-1]

You haven't seen my vacuum sealer bags! I'm using a 1/2 horse industrial vacuum sealer and the bags it uses
are extremely thick. I'll post a photo of my vac sealer, when you turn it on the lights in the house dim and it sounds like a small car

Sounds like an over-amperage condition an a circuit to me, if it's dimming the lights in the house. That could be a hazardous condition. Make sure to plug into a 20 amp receptacle, or at least into a 15 amp with nothing else on that circuit.

 

[PSG-1]

The important thing to do with foam would be to pour it in blocks, sealed in plastic (you are using the plastic to protect the aluminum, not to protect the foam from water), furred up from the hull with 1/2" plastic of some sort. This allows bilge water to flow where it needs to, and grants the aluminum the airflow that it needs to maintain the correct oxidation level, and as such, remain chemically stable.

Amen to that!! This is why I prefer to use foam board, because, unlike poured-in factory foam, the board allows water to flow underneath, through the gutter system of the boat. Factory foam always seems to be clogged in the gutters (anyone that doubts that...dismantle a few factory boats, and you'll see what I mean) Not only does this provide poor drainage, and not only can the foam begin to get saturated (even with closed cell foam) it also leads to poultice corrosion between the aluminum and the foam, eventually causing hull damage.

 

[PSG-1]

The reason I say bagging the foam instead of just using bags of air is that there needs to be weight somewhere otherwise how are you planning on keeping airbags held in on an open deck Jon?

Not sure, but I don't see how foam-filled bags are going to stay in the boat any better, particularly if you started taking on any water. If foam is not placed under a deck, or behind some kind of structural component, if you ever start sinking, you'll be watching the boat sinking under you, while the foam floats out of the boat, and away from you.

 

[MNHunter505]

One reason bags of foam would be better than bags of air is bags of foam won't be affected if punctured.

Side topic...what size plywood is popular for the deck? I have a guy who is selling a 4X8X3/4 marine grade plywood.

 

[MNHunter505]

One reason bags of foam would be better than bags of air is bags of foam won't be affected if punctured.

Side topic...what size plywood is popular for the deck? I have a guy who is selling a 4X8X3/4 marine grade plywood.

UPDATE to my side topic question...found out that it's too expensive for my budget, will go with the exterior plywood instead and switched this subject over to a pre-existing thread already started by someone else...feel free to jump in on that conversation too! thanks.

 

[Backslider]

I used the blue board insulation. I liked it because its easy to cut and fit to the shape of the boat. The other board insulation probably is good for the same reasons. It has made the deck sturdier and more quiet.

 

[MNHunter505]

I used the blue board insulation. I liked it because its easy to cut and fit to the shape of the boat. The other board insulation probably is good for the same reasons. It has made the deck sturdier and more quiet.

Roger, I have decided to use it as well.

 

[Butthead]

Pool noodles on my boat!

 

[MNHunter505]

Pool noodles on my boat!

aaahh, I like that! Hey, how are you going to attach the wood to your ribs?

 

[xbacksideslider]

For decking, out of concern for weight and because I didn't want the weight of carpet and I wanted a veneer to stain, I decided on 1/2" solid core interior grade. It gets wet occasionally, so what? It dries, isn't sitting in a bilge . . .
Underneath the decking, contact cement out of a spray can sticks sheets of white encapsulated construction foam to sheets of the same stuff, and then to the bottom of the veneer.

For flooring, I used 1/8" veneer underlayment, backed up by that same white plastic film encapsulated construction foam. Built up slices of sheets of foam under the floor veneer to change the V floor to a flat floor and to support that 1/8" veneer, for a flat light floatation floor.