Floors in aluminum boat

BlackRussian

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Jul 25, 2014
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Hi, I'm replacing floors in an old aluminum Starcraft boat. It's a v-hull. I removed the floor, underneath there were large pieces of white foam - the same that they use for packing. The foam was porous, it absorbed water (the boat leaked), and it crumbled - it was a complete mess. I realized that I need to use another material. It has to provide enough support. If you take a look at the pictures, these two rails are feeble. So it has to support plywood. And after reading these forum I umderstood that it has to provide some boyancy in case if the boat capsizes. So, what should I use? I realized that it has to be some kind of closed cell foam. I checked West Marine - they sell Evercoat pour foam, but it's a bit pricey. $200 for 2 gallons. Is there anything cheaper? Are 2 gallons enough to fill 16 feet v-hull? What do people usually use? Does it have to be a spray, or I can use some foam mats? What is better - to use mats or spray? I saw some foam mats in Home depot, but I'm not sure that they are suitable for that. I don't want to spend too much money on this old boat, but at the same time I want make things right. The hull is in good shape, the motor is great, so I guess if I make it right I can use this boat for years. Any advice will be greatly appreciated. Pictures of the hull: http://instagram.com/p/q79PwMErpk/ http://instagram.com/p/q79WX4krp0/
 

Jeep Man

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Oct 17, 2008
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Welcome aboard BR. Check out the many repairs and restores in the forum. First item is to stop the leaks. Replace or tighten loose and missing rivets, clean the seams and apply Gluvit to all seams in the interior. You can use "pour in" foam but a lot of guys use blue builders foam from your local building supply. Some have used pool noodles. Pick up some Arouco plywood for the floor (5/8" but I preferred 3/4") and your good to go. Post some pics as you go. We like to butt in and think we're helping.
 

REdington

Seaman
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Apr 22, 2014
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69
I used pink foam from HD. Here is the way I did mine. I primed the hull and installed 1" between the ribs.



Used a piece of aluminum bar stock that I had the measure the depth for each piece. Using a tablesaw with the blade tilted to 11 degrees, I ripped the 2" foam so that each piece was 1/4" higher than what I measured. The top of the foam need to be cut again to get top level so I tilted the blade to 4 to 5 degrees. You want the foam just a hair high so when you put the floor down, it'll compress it slightly and you'll have a solid floor.

 

jbcurt00

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Oct 25, 2011
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if the stringers aren't torn up by damaged rivits or when you demo'd the deck, you'd be surprised how sturdy they become when they are firmly attached to the ribs & the plywood deck.

Open a photobucket acct and copy/paste the IMG code into your posts. The pix show up nice and big and IN your post rather then attachments that have to be opened:
00a0a_16fY4s537RF_600x450_zpsc593b88e.jpg


That way when you have questions, it's easy to scroll back and forth between typing a reply and looking at a pix.
 

BlackRussian

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Jul 25, 2014
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Thank you for the advice, guys. I fixed the leaks, sanded the surface, and I covered all seams with Epoxy resin. I didn't find any Gluvit in my area (i'm in Toronto, Canada). But I'm experienced enough with Epoxy, I did a lot of stuff with it. I found Epoxy at compositescanada.com, they also provided a good filler - Cabosil (very thin silica). The result compound is elastic enough and it sticks well. I'm going to paint the inside of the boat with Rust paint from home depot tomorrow. It doesnt require primer. And I'll definetely check those pool noodles. I checked the pink foam at HD. Will it actually withstand submersion in water? Is it possible to seal this foam with something so that water cannot penetrate it? Thanks.
 

Jeep Man

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Oct 17, 2008
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I'm just down the highway from you. Gluvit is available. I had mine sent to me from the Windsor area. I think West Marine carries it as well. Some members on here don't take kindly to putting fiberglass in a tinny. lol. The sheets of pink or blue foam is essentially the same material as the pour in stuff. It will repel water for a time but will eventually get waterlogged. Keep the center empty to allow water drainage.
 

BlackRussian

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Jul 25, 2014
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Hi Ray, I mean I checked Central outboard marine and a couple of other places, and didn't find Gluvit. And I couldn't wait for delivery. Anyway, the foam bothers me much more now. Are you sure that the pink foam is the same as pour in? I didn't find any note on it saying that it's closed cell.
 

jbcurt00

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The form insulation foam is extruded, NOT expanded. By its nature its closed cell. That's why builders put it against exterior block walls and back fill up to it. It isn't fuel proof, but you shouldn't have fuel below deck anyway.

EDIT: I should have been more specific. The Pink/Blue/Green foamular insulation panels at HD/Lowes is EXTRUDED (XPS). As Jig points out below, white styro bead insulation isn't, it's expanded (EPS), and not a good choice
 
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krakeon

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Jul 14, 2014
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If you check online, the pink stuff at Home Depot or the Blue stuff at Lowes.ca are closed cell.

There's a marine supplies store in Toronto called Noah's (I think it's south of Bloor W, just off Islington). In case you ever need more epoxy. West System has a suppliers page on their site as well.

Imgur.com is a great site for uploading pics. I'd love to see pics of your boat when you're done. I'm working on a 14' Princecraft right now myself.
 

jigngrub

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Mar 19, 2011
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8,155
The pink Owens Corning and blue Dow sheet foams are highly water resistant and good stuff. Stay away from the white beaded Styrofoam, it's junk and will absorb water.

Be sure to do a leak test on your boat before you paint it to make sure you sealed all the leaks. Finding out your boat still leaks after painting it sucks.
 

BlackRussian

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Jul 25, 2014
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Thanks, guys.
I think I'll use the pink foam from HD then. I tested the boat, there were no leaks anymore.I couldn't finish painting of the inside yesterday - the boat was wet atfer the rain, so I finished only half - whatever was dry.
Why should I keep the centre empty as Jeep man suggests? I saw that there are small gaps for drainage under transversal ribs. Besides, I could leave some gaps between foam pieces. I understand that the more foam your stick in under the floor - the better boyancy you will get (if it capsizes)? Or do you think that the foam may get waterclogged eventually?
I'll post some pictures, when I have something to show.
 

Fleetwin

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Nov 23, 2011
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1,141
The more foam you have the better. It will also make the hull quieter.

As mentioned, you need to think like water and how it can travel to aft should it get below the deck.

As long as you allow for drainage, put as much in as you can. Also install it under gunnels. In case the boat swamps, the gunnel foam will help stop it freom turning turtle.
 

Watermann

Starmada Splash of the Year 2014
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Jan 12, 2013
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Looks like your on your way to getting her all fixed up. I wouldn't overlook the need to replace the transom wood, especially if it's not been replaced. In the pic the wood seems very dark but that's about all I can tell. Dark wood can mean rotten wood.
 

BlackRussian

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Jul 25, 2014
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Hmm... Watermann, I didn't think about the transom yet. I just want to take it on water as soon as possible, before the summer is over. Besides, I don't have much time for all these repairs. I'll check how the transom is attached. Maybe, I can change it later - after I'm done with the floors.
 
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