77 allison did they use a layer of wood in the hull between layers of glass?

[derekfl]

xst 18. i pulled one bad spot up in the floor and now it looks like i have to redo the center bilge area of the hull itself. and if this boat was built like a sandwich, can i just add glass to the inside of the hull without some kind of core?

[Mrzip]

.. I don't think you can :nonod:

[KIRCHNER]

i u sed a 2'' hole saw with a shortened centering bit, took core samples in suspicious areas, go about 1/4'' deep,i used a cats paw to pry up the skin, youll see whats soft, mistake3'' i used

[derekfl]

i have grabbed hunks of the inner layer and peeled it away from the outer hull. ok so this is a cored hull with wet delaminated balsa. the inner layer is completely detached from the core over a large part of the Vee section of the hull. (semi-trihull) any tips for removing the balsa from the inside of the outer hull layer?

[KIRCHNER]

i used a hand held floor scraper,wide blade all metal tool, made for use with a hammer. every so often i hit it on a grinder keep blade sharp. [[harbor freight] how thick is the balsa layer? does it look like 2'' squares joined together?

[derekfl]

yes. it looks like half-inch long two by twos all lined up in a grid pattern side-by-side. It’s the center V of a semi trihull. The two sides oh the Vee are about 14 inches wide each and I got about 8 feet in length. That I have to deal with. It had a sort of joke of a stringer that was a piece of plywood bonded to the Keel and only glass halfway up the piece of plywood. I’m thinking of doing two stringers and two crossways bulkhead to make a little box in there. Glass it all down and use it to have the floor hold the hull down in the hull hold the floor up. That, and a couple of layers of mat glassing the whole thing together. I think it will make it strong enough and I don’t even think it’s adding any weight, considering the amount of crap that I pulled out of there. And it’s not a speed demon anyway, so if I add 50 pounds of weight in the bow, I don’t think it’s a bad thing. It’ll make it sit on the flats a little flatter.

[KIRCHNER]

make sure the hull is not supported by the trailer in that area, you dont want to glass-in any destortion from removing the balsa. i would go with 3 stringers fore and aft, not plywood, 1x board. new floor screwed down, #10x1x1/2 ss flat heads8''0/c. paint the under side of floor with any paint you h floorave,2 coats, run a bead of liquid nails down all 3 stringers. glass in the perimeter of n ew floor, try to find 5 or 6 ply plywood.

[derekfl]

so liquid nails would hold the stringers to the hull better than resin? and i am thinking of tryna find a lake to float it in while glassing the bottom up. it has 2 flats either side of the Vee where it sits on the bunks. they are outta the water when on plane. so it probably wouldn't mess with performance if it did get a bunk dent glassed in.

[KIRCHNER]

the stringers need to be glasses in bottom, i use cloth.not mat. you only need to go half way up on the stringers. use 4'' f.cloth, 3 layers will do it. sitting on bunks is ok, even pressure, liq nails between stringers and new floor + screws. make sure all stringers are on even plane' straight or string;so the floor sits perfect. home depot sells 2'x4' panels of real quality plywood, if you have 12'' between stringers, 1/2'' should be good. you might get away with 2 stringers thatbalsa constr was first used by FORMULA, on the entire hull back in the day; bulletproof ofshore boats. the resin would soak in both sides, like a rock

[derekfl]

So, do not liquid nails the stringer to hull before glassing them down? Just resin between stringer and new-laid layer of glass?

[KIRCHNER]

ARE you going to put a new layer down where the balsa was, before you lay the new stringers?

[derekfl]

i am thinking several layers. even if i re-core the hull. which i am thinking i won't do. and this 1708 biaxial mat-cloth hybrid. any thoughts on it?

[KIRCHNER]

i am thinking several layers. even if i re-core the hull. which i am thinking i won't do. and this 1708 biaxial mat-cloth hybrid. any thoughts on it? does the bottom flex when you stand on it now?

[derekfl]

like a trampoline. and i don't actually stand on it. i wouldn't dare. this is just pushing with about 25 lbs force with my toe. now, this is only the 28 inch wide center Vee. the flats that are the "tri-hull" still have two layers of floor on them. the orig allison floor and the add-on layer of 1/2 inch plywood.

[KIRCHNER]

if you glass over some 1x2s running bow to stern, about 6'' apart bottom will be super stiff with minium weight, you can liquid nail down first, so the y dont shift,then come back and glass over. corrugations make super stiff. glass in your center stringer at that time. never had a failure with polyester resin.old school

[derekfl]

i am thinking leave the strip where center stringer was glassed in alone and put 1 either side. maybe butted, maybe 1 to 3 inch gap. then another pair farther outboard. 1x6 should go alla way to floor in center. then 2 bulkheads about 2-3 feet apart. anyway, would liquid nails hold stronger than poly or epoxy? is wet environment an issue? and i thank you for your help and info.

[KIRCHNER]

only trouble with bulkheads is drainage, trapped water. liq nails just for screwing floor down stringers. i would leave about a 3'' margin of old floor to serve as a platform to screw the new floor to. then glass over with fine f. cloth. bring your center stringer up to height of old floor. ive done a lot of glass work, hope i can help.

[derekfl]

you already have helped greatly. i have most of the coring out now. gonna do clean up and first mock up with plywood. they are building homes around here like crazy. there is lots of trash-pick plywood scraps to be had free. and a single drain hole in each compartment the bulkhead creates is not enough?

[KIRCHNER]

.1'' holes. dont forget 1 in the rear of center stringer, a stiff wire brush is good where the balsa was. do you use a bilge pump? also i use a 4'' hole saw put in a deck plate by the transom in floor for inspection.