Decking Replacement - Boat Rebuild

[carpedium]

So... now its time to decide on material to be used to replace my semi-soft decking. I know some here have used advantech OSB with some level of success, but I am concerned with the extra weight it adds. Some other online forums have raved about this stuff for this use. It always goes back to " I've had this piece of advantech floating in my pond for 5 years with no dimensional change or warping...."

This is a ~18 ft aluminum boat. The deck is going to be primed and sprayed with "spray-in" bed liner, so this will also act as a moisture barrier and UV protectant from the top.

Option 1 - Standard 1/2 plywood treated with a few layers of 2-part epoxy for outdoor water fitness. (almost 1.5x cost)

Option 2 - 5/8 Advantech OSB (Need to be treated on cut edges with epoxy?)

I know that the safe bet is to go with marine grade plywood and coat with epoxy, but that blows my budget and with the standard plywood coated, others have experienced similar results.

Any info or experience would be appreciated.

[Has Been]

I saw a guy at the launch last year w/ an alum boat around 18 '. He used 12" wood grain composite facia board. Same thing we use on deck joists for trim. Said it worked great for him. Rivited it down to the stringers. Looked good. Azek also makes a T&G 1X that also looked like it would work well. This stuff is pure poly. Can't rot & it's made for outdoor use.

[carpedium]

Has Been,

Thats a really neat idea. Are you talking about stuff like this:?

http://www.lowes.com/pd_371964-46086-22 ... facetInfo=

I'll have to see if I can get these in 16 footers. If so, this may be a great option. Then I wouldn't need the bedliner, just paint the sides, etc.

[GAMBLER]

Only problem with that material is the gaps between the boards. Any water that gets between the bards is going to soak into your floatation foam.

[carpedium]

Only problem with that material is the gaps between the boards. Any water that gets between the bards is going to soak into your floatation foam.

Yeah thats true. Also will have fish slime migrating down in there.

[Chautauqua Tony]

You can actually buy 5'x12' sheets of 3/4" azak. The stuff would be extremely slippery. I thought about using it on my boat. You would defiantly have to put like a rhino lining or something like interlux non slip paint. Home depot actually has a product called deck renew. Can be rolled on. Kinda like the rhino lining by more pliable. They can tint it too.

[ Post made via Android ]

[buckboardjr]

I saw a boat done with exterior plywood and then he glued Linoleum on. At the time I saw it he said it was 8 yrs going strong. He got the stuff on discount super cheap.

[lineman49]

All that stuff seems like a good idea, but what about getting fish slim / wet & slippery ??

[carpedium]

All that stuff seems like a good idea, but what about getting fish slim / wet & slippery ??

Yeah, for the cost i'm leaning toward the advantech with the bedliner. Its nice and textured so it won't be slippery and it will keep the foam dry and free of slime from the top anyway.

[J.D.]

Instead of bed liner, check this out.

http://www.tuffcoat.net/wordpress/

[buckboardjr]

I want to try building a set of planner boards out of that deck trim. I wonder if it floats a little?

[rolmops]

I talked about the same question with an engineer friend. He told me that any 1/2 inch plywood if it is well painted (2 or 3 layers) will last for 10 to 15 years. That being said, an 18 foot boat floor is not always flat.It often comes up from the sides to the middle (don't ask me how I know) and in that case it is very hard to screw the 1/2 inch boards down, a good way to go then,is by using two 1/4 inch layers which you lay down one after the other. That way you will not have any problems with the curving.

[t2al]

I woud use aluminium tread plate,will never rot

[carpedium]

Well, a buddy came over to help me out - ended up getting the thing stripped down. There was an extra 120lbs of water soaked into the foam alone. What shocked me was that the front half of the boat was completely foam with no void in the middle to allow any water to flow out. This was from the factory. The decking was in horrible condition. Turns out i was just walking on wood pulp over foam.

[rolmops]

Keep those pics coming, they tell a great story!

[buckboardjr]

I did this exact strip down on a 19.5 ft Sea Nymph Great lakes special in 1999. My pics from back then are on film. I cut a square chunk of foam, about 18in by 18in, out of mine that was saturated in water and it wieghed 20lb. I set it on a shelf and after it evaperated it was less than a lb. When I went and priced the foam it was gonna cost $300 from boat places. I bought mine local from a place that repaired wrecked stainless steel milk tankers. Got it for $100 and the quaility was better for structual strenghth. I know your on a budget but I went with marine plywood, marine spar vanished undersides and edges, then coverd with marine vinyl from cabelas. That's great that you are bringing it back to life. WTG

[Has Been]

Amazing to me that the foam absorbs water like that.Couldn't they use some sort of closed cell foam that wont absorb like a sponge? They must have known it would. Looks like its built to fail to me.

[buckboardjr]

I was told that trapped water, left to freeze, is what ruined the closed cells and allowed it to absorb. Don't know if that is true or not.

[carpedium]

Thanks for the words of encouragement!

I have also heard that about the freeze/fail with the foam, buckboard.

I plan to go back in under the decking with blue insulation closed cell foam. I like this method because it creates channels where trapped water can escape back to the stern between the angled foam pieces. It then eliminates the possibility of further freeze/fail when/if water finds its way through the decking near the bow of the boat.

[carpedium]

Does anyone have an idea on what to do with this boogered stringer-end?

My first thought is to remove the rivets, and add some AL bar-stock extending 6 inches or so down the rib. Then riveting the bar stock to the good part of the rib/hull in two places and replacing the other rivets with new, through the bar stock.

Either this or weld it. I don't know which one would be more difficult.

[carpedium]

Would anyone object to these for decking screws?

http://www.grainger.com/Grainger/Tappin ... crew-1VE74

[carpedium]

Like this paint scheme:

[buckboardjr]

Matt, That repair to the stringer sounds good provided you are going to use solid rivets and buck them as original. In one of your other threads I noticed you said the rivets were 1/4". I thought all of the rivets I delt with were 3/16 on my sea nymth. Are you sure on the 1/4 dimension? Solid rivets are the way to go on issues with your hull. They really aern't that big a deal once you get going.

[carpedium]

Well, I just made a phone call to a local welder and he happened to have some time on his hands to weld up all the cracks. He's also going to beef it up in some spots to make it stronger. He's basically doing it for what it would cost me in materials for bar stock and other non-pop rivet tools. It will be done in less than 24hrs.

Buckboard - I agree. I wouldn't want to use the poppers in this application either since there is obviously a lot of stress concentrated in these areas with no fastener redundancy like the rest of the hull.

[carpedium]

On the size of the rivets, I am going one size up to be able to true-up the hole properly. Plus the larger rivets are rated for like 66% more load vs. 3/16 per the manufacturer.