"sealing" a new wood floor in a aluminum boat

[root beer guy]

I have completely gutted my 1981 16' blue fin, and need to put it back together.

this is my first boat project, but I am a machinist of 17+ years, and with plenty of home remodeling experience too.

I need advice on replacing this floor. I have heard a good exterior grade is okay to use, but I am wondering about the edges where the wood meets the aluminum boat.....the wood will be covered in carpeting when finished, but I am confused about drainage. do I want a perfect seal all the way around, so essentially the water runs all the way ("on top") back to the bow and then down to the bilge pump, or, do I want a sort of "drain holes" in particular locations to let the water run under the existing floor?

I ask this because everything I pulled out of the boat was rotten, I have nothing to go by.

also, I have a ton of left over waterproof membrane from working on my bathroom. this is the kind of stuff that you put behind tiles to prevent any and all moisture from getting to the wood. I am thinking this may come in handy for creating a dry storage area, or sealing up any edges I don't want water to get through.

attached is a pic of the current state of the boat, bare alum, it has since been power washed.

the old floor had a bunch of styrofoam blocks hap-hazardly placed, I am guessing these were installed by the previous owner to try to create some more support. I personally plan to try to beef it up a bit more with wood, running length-wise down the boat.

thanks for any and all advice-

 

[jasoutside]

Re: "sealing" a new wood floor in a aluminum boat

Hey root beer, lot of good questions there.

Just one fellas opinion, in short...

-You don't want the wood deck coming in contact with the aluminum hull. You'll want to have a small gap there so the water can make it's way down into the hull, into the bilge, over the side via pump.

-Having flotation that helps that drainage is key. Many of the guys around here use pink/blue foam board or pool noodles for flotation. This stuff helps with drainage vs. pour in foam.

-Exterior grade plywood is totally fine. Seal it up with epoxy, or porch and floor paint, or poly resin and fiberglass.

-I'm not so sure a plastic membrane would be very helpful for ya. My humble opinion on these boats is that you really want to work with the water, letting it go where it wants to go, getting it back out over the side, and allowing things to dry out.

-Click on the "Starcraft Rebuilds" link in my signature and you'll see great ways to put these old metal boats back together.

-Again, just one fellas thoughts. There are a lot of different ways to go about it.

-Welcome to iboats!

 

[jigngrub]

Re: "sealing" a new wood floor in a aluminum boat

We really need to see a picture of the overall inside of your boat, maybe one from bow looking back and the from the sten looking forward.

My opinion...

The foam may have been placed in there for support, buy probably for floatation too. You need floatation below your deck.

I wouldn't use wood to shore up anything below deck, use aluminum tubing or angle.

As J said you decking doesn't need to fit tight.

I would suggest you use marine vinyl instead of carpet, carpet soaks up water and holds it.

For the decking use exterior grade plywood, the glue is waterproof.

If your deck was rotten you should check your transom for rot too, more than likely it will need replacing as well and it's better to do it when the boat is already torn apart.

 

[root beer guy]

Re: "sealing" a new wood floor in a aluminum boat

thanks for the responses!

I will read through jasoutside's posts as soon as I get more time.

I am attaching another picture, one that was taken before I completely cleaned it out......it was infested with thousands of carpenter ants.......

as I understand it, I can use a good exterior plywood and should not seal it to the aluminum (edges). as far as sealing the wood itself goes, I should still seal both sides of it up with floor paint, epoxy, or fiberglass and resin as suggested? when you refer to resin and fiberglass, this is the same sort of stuff made by brands like "bondo" right? I want to make sure I use the right suff. this is also the type I could use to seal a new transom also?

the transom is shot.....I have been reading posts on here about it. I am planning to use the same exterior grade plywood epoxied together, then sealed with resin and fiberglass mat.

the carpet I had planned on using is the indoor/outdoor "all weather" stuff they sell at menards, with a rubber backing. I have only glanced at it, I will take a closer inspection next time I go. is there anything special I should look for?

now as far as floatation material goes, I also have on hand a bunch of the pink foam (closed cell) 1.5" thick insulation. I think this is what you are refering to to use. as I understand it, there should be a good amount in there, but not so much as to block water flow.

please advise with any other suggestions, thanks again.

 

[jigngrub]

Re: "sealing" a new wood floor in a aluminum boat

In your second pic it looks like you just have the center stringer and maybe an angle around the perimeter to fasten the decking to? If this is true your boat came from the factory with 2 part urethane foam poured in the bilge after the decking was installed, this was the main support for your deck. You won't have a solid deck if you just lay the plywood over what you have now, it'll feel "springy". If this is the way you're going to do it (not recommended) I strongly suggest you run the decking with the grain running from side to side and not front to back.

There are better ways to put your deck back in your boat, and if you're interested I'll explain them to you.

 

[third times the charm]

Re: "sealing" a new wood floor in a aluminum boat

hey rootbeer, check azlo post as well, hes is redoing a 68 hoilday. He has some great step by step pics of the floor and what he did to reframe his

 

[root beer guy]

Re: "sealing" a new wood floor in a aluminum boat

thanks again everyone-

jigngrub, I would love to have you explain everything you can to me, I have allot to learn about this.

I have acces to allot of 1.25" square aluminum tubing, its hollow and the walls are .090 thick. I am thinking of screwing the wood down into this, if I run them left to right to try to reduce the springy-ness.

it was VERY springy when we first got it, and that was part of the reason I pulled it all up, along with the obvious rot after I pulled up the old coverings.

 

[jigngrub]

Re: "sealing" a new wood floor in a aluminum boat

That tubing will work very well, just run a ledger angle on both sides of your stringer like you have on the perimeter and rivet your tubing to both angles on each side for your framing. 24" centers should be ok with 3/4" ply and 16" centers for 1/2".

Here's a link for the marine vinyl if you should decide to use it, it'll let the water drain off the deck instead of sucking it up like a sponge like carpet does.

http://www.defender.com/category.jsp?path=-1|10918|311409&id=311410

I'll be puting it in my boat as soon as I get the decking prepped and you can see how it looks.

 

[fishrdan]

Re: "sealing" a new wood floor in a aluminum boat

Not sure if this was answered, but don't use the waterproof membrane, it will eventually get moisture below it and won't be able to dry out,,, a recipe for rotted wood again. Also, this is a good reason to leave a bit of a gap between the deck and hull, so air can get in there and dry things out.

For the deck, I wouldn't go 3/4 if you are going to glass/resin or epoxy the wood. I used 3/4 marine ply in my 18'er and the decks are SOLID! (No glass or resin, just treated it, dry desert environment) But, I also added 150# of extra weight..... Epoxy or glassing the decks will add a lot of rigidity to the plywood, so 1/2" 5 ply exterior, glassed, could be as rigid as plain 3/4. I haven't done it, but others have said it worked very well.

For the decks being springy, I wouldn't over-engineer your rebuild because of how the old rotted wood felt. If it was 1/2 ply stock, you will be making the decks much stiffer than originally built by glassing or epoxying them. How wide is your widest unsupported deck span? On my rig it's about 28x48" over the belly tank, which felt springy before putting in the 3/4 ply, original was 1/2" ply with 2- aluminum 1x4" U channel stiffeners. Honestly, I wished I had used 1/2" exterior 5 ply, glassed. Less weight and probably as rigid as unglassed 3/4 ply

If this a fishing rig I would go with the vinyl jigngrub posted up. I just got back from fishing and it was easy cheesy cleaning up the blood and carnage from catching 30 dink stripers last night. When I get a "gusher" I just grab the bucket of water and hit the decks, washes the blood away easily. Not so easy with carpet. The only reason I would go with carpet is for the "quiet" factor. Vinyl can squeek and dropping or dragging things across it makes a lot more noise than carpet. I have carpet in my jon boat, (stealth big striper fishing rig) and wouldn't put vinyl in it, too noisy....

 

[rwhodel]

Re: "sealing" a new wood floor in a aluminum boat

Rootbeer, I have a 19' Bluefin Sportsman that I am just about completed the restoration.. I relpaced the deck because of rot with 5/8" exterior plywood and finished it with Rustoleum marine paint. I just installed a new transom and am just about finished with the whole boat. My deck is about 3/4 " from the side of the boat and I used pink foam that I got at Home Depot.
Here is a link to my restoration project.
http://forums.iboats.com/showthread.php?t=376040

 

[root beer guy]

Re: "sealing" a new wood floor in a aluminum boat

thanks for the responses guys.

Just to be sure, the resin/fiberglass mat that is reffered to here is the everyday stuff made by brands like "bondo" right?

I am thinking of going with floor paint, just because of the ease of use and time involved. would I use oil or latex? how long does this stuff hold up versus the fiberglass?

jigngrub, I want to make sure I understand you correctly, you are saying attach the tubing the the existing stringer running down the length of the boat, to give me a larger (more stable) surface and provide a area to attach the floor too, and then run my supports perpendicular to the stringer (left to right) attaching to the ledger and the stringer? I think I got that.

it is going to be the family fishing boat, nothing real fancy, but I will install the live well over again and put in some new seats and a rod locker.

 

[Cadwelder]

Re: "sealing" a new wood floor in a aluminum boat

thanks for the responses guys.


I am thinking of going with floor paint, just because of the ease of use and time involved. would I use oil or latex? how long does this stuff hold up versus the fiberglass?

No comparison between paint alone and fiberglass. CSM and resin will far our last any paint you use. Personally the painting idea is fine, but I'd paint over the fiberglass and then you'll be set for years and years to come.

Seal both sides of your plywood and you'll be fine. The back side doesn't have to be pretty, and on the top side you can just roll the resin and matt good let it cure and then paint, it should look fine.

 

[fishrdan]

Re: "sealing" a new wood floor in a aluminum boat

No comparison between paint alone and fiberglass. CSM and resin will far our last any paint you use.

^^^ Yup

You can use Rustoleum, it's a good bang for the buck oil based paint. A gallon is about $25.