Stringers and Transom - cloth weight

[MercMark]

I'm about to start redoing the transom and stringers in my 15' thundercraft wildcat. It looks like a small checkmate. It has an in line four cylinder merc 850 (85hp) outboard.

The gang at iboats reccomend one layer 1.5 oz mat, 18 oz woven roving, another layer of 1.5 oz mat, and another layer of 18 oz woven roving.

I talked to local suppliers and they said this is overkill and will add excessive weight to my small boat.

The supplier reocmmended two or three layers of 6 oz cloth for the stringers. I will use roving to attach the transom to the hull.

The boat is used for cruising at speed up to about 45 or 50 mph, and water skiing on inland lakes only (no ocean size water, probably not even great lakes)

need advice. will be using West system epoxy.

[yokebutt]

Mark,
Since you're using epoxy, there is no need to use mat, and roving is just a bitch to work with if you have a lot of contours and tight corners to conform it to.

My favorite way to laminate internal structures is to alternate cloth (6 or 10oz) with 45 degree biaxial fabric without a mat backing. (12 or 17oz) What you do is cut all the fabrics to the right size, make the cloth pieces a little bit bigger than the biax, (1/2" around the perimeter, or so) then, on a piece of cardboard or similar, you wet out a piece of cloth first, then you add the biax on top and wet it through too, then you can roll the two up together and stick them in a bucket.

Wet out a whole stack of those, and then bring them all into the boat and install, the cloth/biax combo will keep it's shape well enough to handle, but still has enough malleability to conform to complex surfaces.

But of course, before you laminate, make generously sized radiuses in every corner, so you don't get any line-bubbles.

Yokebutt.

[yokebutt]

PS, I gave some similar advice on a thread called chainplate bulkhead or something like that, look it up.

Yokebutt.

[MercMark]

Sounds like an unusual method, involving a bucket. I may do only one stringer at a time to reduce the risk of deforming the hull. I'll go digging for that thread now.

[yokebutt]

Mark,
The idea is to take the glass back out of the bucket BEFORE the resin kicks, but you probably already figured that out. Don't worry too much about the curing resin distorting the boat, epoxy shrinks a lot less than polyester.

Good luck,
Yokebutt.

[MercMark]

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