my first re-build how do i glue new wood to old fiberglass hull?

[wiseman79]

this is a 16 foot fly fishing boat to be, i got it cheep of ebay and on my first run with a 30 hp yam the hull flexed about 50-100 mm the same with a 15 hp, i was going to ditch it but found my self caught in 20-30 knt winds and very sharp 2-3 mtr wind slop in the lake, and it got me home, so i can trust the hull if i go stedy, but am i doing the right thing with this design? the half ribs the decks will thay cause it snap in half? How do i glue the wood to the old glassed? tha hull is a heavy weeve cloth, it only had 3 pices of timber in it for seats with a bit of vinal wrap, nothing is glued or glassed yet, im not even sure what to call this design hull, aney help would be great thanks
regards matt

[bntii]

Just a couple of thoughts-

This sort of work is done by laying up layers of fiberglass cloth over the wood stringers and floors you have fited to 'glue' them to the hull. One starts by grinding out the hull and tacking down the parts with some thickened resin. New fiberglass is then drapped over the part and onto the hull. The fiberglass should extend about 3" onto the hull. When done the hull will be substantionally stiffened. I would guess about 1/8" of new glass over the stringers and a bit less over the floors should do the trick if done with epoxy. Care must be taken to insure that no water can get under the glass or the wood under will quickly rot.

Grind out to raw glass in all areas where you wish to lay up new glass

Bond down the stringers with epoxy thickened with cabosil and use a rounded corner of a paint stick to slick some nice rounded filets down each side.

Lay up the laminate over the longitudinal members first with good continuous laminate to insure water won't get to the stringers.

When placing the cross members provide some drain holes along side the stringers and amidships to allow water to get aft to a pump.

Use epoxy with slow hardener to allow plenty of working time.

If the ply deck is really well fastened it will lend a great deal of stiffening to the floor. Coat the underside with epoxy.

Maybe provide some ledgers along side of the floors to screw the ply deck to.
This will insure that water leaking down the fasteners will not get into the
glassed shell over the floors.

Glass the deck with some 9oz fabric and sanded paint over.

Looks like a very nice careful job done so far.

[wiseman79]

thanks for the reply mate,

i cant wait to get her back the water and nail a big wild brown trout.

i went to the hardware aufter i got your post and got some flap disks, a corse grit wheel ment for metal there not as hars as a grinding disk thay go on the angle grinder.
i got some poly resin last week shuld i take it back and stick with epoxy the hole fit out?

i was thinking that maby the glassed over floor wuld act as a self draining deck in to a bilge area?

wuld expandabul polyesta fome for added flotation under the floor cause more flex agane, because of the mass of area?

thanks heaps agane for the reply.
regards matt

[PAR]

Flexing in the hull isn't unusual, in fact it's expected and accounted for in the laminate design. Some boats are designed to flex a great deal, so they can give a little, with the on coming seas or twist as it rides over rolling waves, etc. If they didn't flex, they would ride like bricks and things would break.

Frankly, you don't need additional stiffing in this size boat. She's appears to have a heavy rove layup, which will be pretty stiff and heavy. Since you've made up a new interior and have the pieces ready to install them, go ahead and bond them in with epoxy and cloth tabbing. Coat all the wood with epoxy, including notches, screw holes, everything, with special attention to the end grain areas of the ply, where they are most vulnerable to moisture. Every sq. mm. of wood should shine all over when epoxy coated properly.

I noticed you haven't installed any weep holes in the athwartship pieces. These need to be there and are little more then notches on or near the centerline of the boat, to let moisture run aft to a transom drain (you can't have too many weeps). Even though you may be sealing in the floor, moisture will find a way to get in there and it should have a way to get out, or it will rot the wood. Of course, store the boat bow high so it can drain naturally, when ashore.

Add some closed cell polyurethane foam to the bow area and under the aft deck area, if you want to. It will provide floatation if you get swamped, but it will do little with the flexing (which is okay).

Your workmanship looks good. Try not to add too much weight to this boat, she can only handle so much, before she becomes over burdened and performs like a pig. You're off to a great start, keep up the good work and send more pictures as you get further along.

[wiseman79]

thanks so much for the advice PAR

i will put them drain holes in for sure, thank you, i plan to use her long term to fish lakes and bays.

do you think i have put to much weight in there alredy? i guess there wuld be 100kg of wood with the floor, decks, stringers, half ribs, and console.
from the old glass work and a now covered forwad bung hole and the infomation from the seller it was a fresh water crab boat in the top end of australia, and there may have been a well forwad of midship i think it was built to carry a load in calm crock infested water. im not 100% sure on that, its just what i can come up with.

on the last coats of glass how do i tie the decks, console, and floor in to look like one layer? or can i ues a spray putty like under coat and sand that up? both decks and floor will have carpet.

she has a beam of 1.9 mtr`s and very stable at rest.

youre post was great thanks mate.
regards matt


here,s a shot of what she looked like before i got her.

[Oyster]

http://www.classicmako.com/projects.htm

The above link shows step by step many fiberglass hulls and steps along the way. Some of the rebuilds are pretty extreme with workmanship and top of the line materials being used, too. But the general principle is in most of the links. X-Shark is one of the most well documented rebuilds of all time.