Styrofoam Installation

"One day.....tin boats will rule the world....one day"

Hello there fellow tinboaters,

I got a quetion about my 14ft jon boat mod. Before I bolt down my deck I want to put some styrofoam in the hull to help out with the weight and to maybe keep me floating if I hit an iceberg out there. Where can I find some cheap styrofoam? I just got back from Lowe's and they were asking $40 for a short stack of styrofoam! Home Depot sells 1/2 inch sheets for about $20. I'm over here in Camp Lejuene, NC so does anybody know somewhere close I can go or somewhere online? Also, is spray on styrofoam just as good? Please let me know tinboaters......I just got the plywood for my deck and I'm ready to get this mod finished.

Keep a weather eye on the horizon,
sheffsboat

If I were looking for REALLY CHEAP Styrofoam...I'd be cruising the dumpsters behind the big box stores ... Best Buy etc.

Also, auto mechanics get large parts shipped in Styrofoam. I found some (to be used for a model airplane project) up at my local gas station. They shipped a rebuilt transmission in it..

The shipping packaging has cutouts and indentations, but none of that should bother you if you cut your pieces up and fit them into the boat.

Personally, I would put all the Styrofoam into a double plastic big before stuffing it into the boat. That should help keep it out of the water which will, sooner or later, get into the hold. Rich

Yeah, you can look at it like foam costs x $$$ per sheet. Or you can look at it a different way, foam is cheap insurance... and you only have to buy it once if you buy the good stuff.

Figure up how much money you have invested in your boat and motor, plus add up the cost of your fishing tackle that'll be in your boat if it sinks.

Then figure up how much foam you're going to need, if you have a 600 lb. max capacity you'll need 10 cubic feet. 10 cubic feet is just a little less than 2 4x8 sheets of 2" foam or 8 sheets of 1/2" foam. Even at 20$ a sheet, that's $160. Is your boat, motor, and all the stuff in your boat worth $160? If not, ship the foam and put your deck down. If your boat is worth more than $160 than buy the good foam.

When you're adding up the cost of everything you may also want to include how much your life is worth, not having enough or good foam may cost you your life too.

+1 to what jigngrub said. Let me tell you a story about what happens when you decide to skip on flotation foam.



Several years ago, I bought a used 16 foot Crestliner, the previous owners has removed all the decking, flooring, etc, so that the ribs could be welded and repaired....but then they ended up getting a new boat.

Since this one was fairly well gutted, I think I only paid 500 dollars for it. But, all the panels and everything were still in the boat, it was just torn apart. Since it was going to be my girlfriend's boat, she was helping me put it back together.

When we went to install the false bottom/floor, I said "this thing really needs some 1 & 1/2" styrofoam panels under the floor." After all, this is what I had already done when I built my jetboat, as well as my 14 foot DuraCraft.

My girlfriend says don't worry about it, not to spend any more money on the boat....and against my better judgement, I listened to her.

Well, we got it all put together, found a used 30 HP Johnson outboard for about 500 bucks, and everything ran good. We used it out in the creek for a while.


We had it tied up at the dock, and the tide went way out one day, leaving the boat sitting on the mud. Which would have been fine, except for the fact that the boat was sitting at an angle, with the bow being a good bit higher than the stern, and not only that, but the stern had also been cut down, to allow the motor to fit. And where the stern was sitting, there was a hole, with about 2 foot of water at low tide, from where prop wash had blown out a hole next to the dock.

So, the high angle of the bow, and the low stern, allowed water to flood right into the boat on the rising tide. And with no flotation foam, guess what happened? Yep, she sank, and when I say "sank" I mean to the bottom.

We had to wait for the next low tide, then, had to attach a come-along to a bridle hooked to the transom, then hooked to the piling of the floating dock, to be able to lift the transom high enough that it was above the waterline, so we could pump the boat out.

Once we got it de-watered, and hauled out, then came the task of rinsing everything with fresh water, having to use compressed air to dry all electrical connectors, then putting dielectric grease on all of them. It was a MAJOR PITA to get the engine running again, but we did.

At that point, I told my girlfriend not to put that boat back in the water unless we ripped up the decking and installed foam. After seeing how it sank, she sure as hell didn't have any inclination to go back on the water with it as it was.

But rather than re-do the decking, we ended up selling the boat to someone else for next to nothing, with the cautionary statement that there was no foam in the boat, it either needed to be re-done, or use at their own risk.

Lesson learned: foam is VERY important in a boat.

Also Remember that there are two kinds of styrofoam; Expanded and Extruded. Expanded soaks up water at a much,much faster rate than extruded. Use extruded,you'll be much happier with it.

shellfsboat...the foam will actually only make your boat heavier and not help with the weight.
Pool noodles are cheap and watertight,the right amount should keep your boat afloat,if swamped.

PSG-1...not sure why your boat sank(other then the no foam part).The bow being higher then the stern,doesn't seem to fit(atleast in my mind).Wouldn't it just rise until even,anyways guess it doesn't matter.

Zum said:

shellfsboat...the foam will actually only make your boat heavier and not help with the weight.
Pool noodles are cheap and watertight,the right amount should keep your boat afloat,if swamped.

PSG-1...not sure why your boat sank(other then the no foam part).The bow being higher then the stern,doesn't seem to fit(atleast in my mind).Wouldn't it just rise until even,anyways guess it doesn't matter.

Click to expand...

If the boat is on a bit of an incline when it ebbs out, with a cut-down transom, it's quite easy for water to simply spill right over that low spot, and flood the boat.

Had another boat sink at that same spot, except, it was an 18 foot Alindale skiff, and it did have flotation foam.....so, it didn't really sink, but it sure as hell wasn't floating, let's just say that.

What happened with the alindale was that as the tide came up, the water ran onto the deck, via the self-bailing deck scuppers, as the stern was squatting low. Which would have been OK, except that the round hatch plate that accessed the inner hull, had a bad O-ring, and/or a cracked cover plate, and this allowed the water to flood right in between the hull and the deck, adding enough weight that the stern wouldn't float up as the tide came up, causing it to sink.

But the difference in the 2 boats was that I was able to drag the alindale over to the ramp and get it de-watered, it wasn't sitting on the bottom until the next low tide, unlike the Crestliner.

Zum said:

Pool noodles are cheap and watertight,the right amount should keep your boat afloat,if swamped.

Click to expand...

Pound per pound of floatation pool noodles are actually more expensive than sheet foam and they take up more roomfor the same amount of floatation.

Sheet foam is your best bang for the buck.


Hey Sheff, I don't know what's up with your HD store... but around here we can get the 4x8' sheets of 2" foam for about $35:

https://www.homedepot.com/h_d1/N-5yc1v/R-100320352/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=foam+insulation&storeId=10051

you can order this stuff online and pick it up at the store without having to pay a shipping and handling charge.

Pound for pound pool noodles will withstand the elements far longer than sheet foam. Leave sheet foam in the weather a few months and see what happens.

Bugpac said:

Pound for pound pool noodles will withstand the elements far longer than sheet foam. Leave sheet foam in the weather a few months and see what happens.

Click to expand...

Cut 6 pool noodles up into 12" pieces and try to fit all the pieces in a 12"x12"x12" box and see what you get, then check to see if that box full of noodles will float 60 lbs of concrete.

jigngrub said:

Bugpac said:

Pound for pound pool noodles will withstand the elements far longer than sheet foam. Leave sheet foam in the weather a few months and see what happens.

Click to expand...

Cut 6 pool noodles up into 12" pieces and try to fit all the pieces in a 12"x12"x12" box and see what you get, then check to see if that box full of noodles will float 60 lbs of concrete.

Click to expand...

have you tried it?

jigngrub said:

Zum said:

Pool noodles are cheap and watertight,the right amount should keep your boat afloat,if swamped.

Click to expand...

Pound per pound of floatation pool noodles are actually more expensive than sheet foam and they take up more roomfor the same amount of floatation.

Sheet foam is your best bang for the buck.


Hey Sheff, I don't know what's up with your HD store... but around here we can get the 4x8' sheets of 2" foam for about $35:

https://www.homedepot.com/h_d1/N-5yc1v/R-100320352/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=foam+insulation&storeId=10051

you can order this stuff online and pick it up at the store without having to pay a shipping and handling charge.

Click to expand...

The HD here where I live doesn't carry the thicker stuff, either, I think 3/4 is the thickest they have. But the pink or blue foam board is what you want to use, as it's the most durable and water resistant. The white bead styrofoam board will also work, but the beads tend to break down and make a mess.

I used 1 & 1/2" pink foam board on both my boats, I got it from a friend who had a few sheets, but 2" would be even better, as long as the height of the ribs in the boat will allow for it, and most modern boats with square channel ribs are 2"

Bugpac said:

jigngrub said:

Cut 6 pool noodles up into 12" pieces and try to fit all the pieces in a 12"x12"x12" box and see what you get, then check to see if that box full of noodles will float 60 lbs of concrete.

Click to expand...

have you tried it?

Click to expand...

Don't take my word for it, try it for yourself because seeing is believing.

The best kind of foam to use in a boat has to be one of the most debated subjects on the forum, so I'm not even going there :LOL2: .

However there is no doubt in my mind that you want the proper amount of foam in your boat. If not for your personal safety, as stated before it's cheap insurance for your boat and equipment. Really unexpected things can happen on the water, quickly!
Over the years having foam in my boats has been a big benefit a couple of times. Once a number of years ago my wife and I were fishing on what was beautiful summer day when the sky suddenly turned black and the wind started howling. We headed for the landing and found a couple with two small children struggling to get their tin on the trailer in the wind. We tied out tin to the dock and managed to help them get their tin winched up on the trailer when the skies opened up. They took shelter in their car and we in our truck. I thought it was never going to stop raining. When the rain finally stopped our boat was almost full of water tied to the dock. It was sitting low, but still floating with the power head of our 50hp out of the water!
We managed to get it on the trailer, drained and dried out it was as good as new.