Taping seams on a barge ??

I'm close to taping the seams on this 44' X 14' barge. I inheitited it from a fellow embroiled in a divorce. He failed to build in any longitudinal strength, 3 rd. pic shows "just" ribs. No chine boards, no keel. It is tripled layered plywood, each sheet running at a 45 to the previous. I also plan to lag bolt 2 X 12s along the sides where the sides meet the bottom, and add a double 2 X 12 keel. STILL, I fear a "wet noodle" tendency when the crane turns it.
It's destination and purpose is a base for a floating shack. It will never travel far, or in rough waters. I'm confident of it's purpose, but worried about handling it on land.
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I'm worried about the tape,(12" biaxial), tearing or pulling if I use regular epoxy to bed it. Some claim to sell flexible epoxy or some sell a flex additive.
What do you think?

 

With a triple layer of plywood, you'll gain a substantial amount of longitudinal stiffness. This coupled with the additional efforts you plan, suggests you'll be fine, though be gentle with it during the roll over. Use lots of material with the seam taping. Use several layers of fabric, not one or two heavy layers.

 

The pictures don't reflect the present hull. The edges have been trimmed, the 2 nd. layer is now on.
The 3 rd layer is non treated exterior ply. All layers are 1/2". The final, (3 rd.), layer is to enable coatings to adhere. No one would garruntee their product to stick to the ACQ ply sheets.
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I'm encouraged to hear your opinion on the rigidity inherent in the 3 ply skin.
As for the multiple tape applications...., OUCH! 44 times 2 + 14 times 2 +6 times 4, IS a lot of tape, the 1 st time around. To double or triple that length is a staggering thought! What benefit would I gain.? All I want is water proof, stationary dock.
Do you feel it necessary to buy flexible epoxy, or a flex additive? I should mention, the submerged portion of this hull will get 2 coats of coal tar epoxy.

 

The multiple layers are much more water tight and will mitigate most chances of a pin hole or other missed gap messing up your launch day. Epoxy alone will just seal the plywood, nothing else. Fabrics impart strength, dramatically increase abrasion resistance and waterproofness. Instead of buying tape, just get enough bolt length fabric and cut it down to tape dimensions. Yep, you'll have a bunch of lapped seams, but it's a barge, not a racer. If using a 90/90 cloth, cut on a 45 degree bias which will permit you to go around the "corner" so much easier (and it's stronger), though you end up with a bunch of little triangles of fabric that are difficult to find a use for. The other option is a pretty heavy radius on the chine, which will permit you to lay the fabric with the bias.

 

im sorry man,,,im not even close to being able to help you,,,,but ya barge,,reminds me of my friends and mine,,,was a 4x8,,like yours,,,,just REAL smaller,<(maine word),,and we had an ancient 2 stroke 9.9hp gravity feed outboard (had 2 cans of corn"cat ate the corn hehe" for a fuel tank),4 gallons of poly resin,,and would never run cept the day we planned her maiden voyage (memorial day camping trip to an island) and wow,,,,took us 5 hours to get there ( other friend had 16 foot aluminum with 5hp,, and took him 20 minutes),,,but,,,,,sorry to waste ya time,,had to get that out

 

OK. I didn't mean I wasn't going to use "any" cloth, just wanted to sneak by with one layer. I will bow to experience and advice.
I have considered protecting the seams by laying strips of ply, (say 16" wide), over the seams, like strakes. Then coating the bottom with coal tar. I imagine this thing will be loaded onto a flat semi trailer for the 1 mile ride to the ramp.

 

Two coats of epoxy over your underwater areas is below my minimum recommendation for coating any plywood, particularly underwater areas. Two coats will still have slightly dry areas, where the resin soaked in more then other areas. Three is my minimum and more wouldn't hurt, though you're not gaining much after three without reinforcement (like fabric).

This boat's going to be heavy enough that you're not going to want to haul it out any time soon after launch, so over killing the bottom would be my approach. Over doing your seams and bottom is cheaper then under doing them, in the long run.

 

That last part make perfect sense, & I will comply. Thanks