1968 Saftmate - Stringer Work and Question

I think youre seeing the resin/csm filler the last shop used to bond the floor to the hull at its perimeter.

In regards to the roving, this would be my fault, as I laid this in 1997, as a teenager. The crack looks not to involve the hull though?

 

Here are more close ups of crack.

 

Stress crack from improper work as the other poster said.

There is no way to tell if the hull is related by a picture review, but given the facts; it is probably just from no fillet.

If it bothers you or you worry about ingress you can sand the area with 36 grit floor paper and clean and trowel over an epoxy/cabosil paste about 1:2 by volume and make fillets each side and lay a piece of glass over it. You will need about 3-6 ounce epoxy. Make the fillet with say a 1" or 1.5" rounded stick. I figure fillets at 16" per ounce of epoxy give or take.

The stringer tabbing also needs fillets if none.

It is easiest and best to fillet and glass immediately versus sanding fillets. You get all primary bonding (sort of) and no sanding.

 

Thanks you mean grind off the tabbing, and fillet the joint where stringer meets the hull?? I was thinking of reglassing all 3 stringers with 1708 anyway.

 

Do fiberglass hulls have a lifespan if not abused? Meaning does the hull eventually fatally fatigue crack and become scrap??

 

Pretty open ended question. A lot of factors to answer that one.

Generally, no.

I have seen all different forms of hulls fatigue and be done.

The more common death nail to glass boats nowadays is core rot. But I think your boat predates balsa core.

If you hang off the gunwhale on one side of the boat and the hull twists; there is a sensible solution and that ain't more glass, imo.

When you started talking about adding a bulkhead; you had me a little worried is all. No need to go down the rabbit hole on terminology confusion.

 

Just sand it for keying for the secondary bonding.

I would also use epoxy.

 

Thanks. So do I grind off all the CSM and woven tabbing on these outboard stringers (wood is good underneath), or can I just sand clean, and wipe with acetone?

 

Sand it for smooth transistions.

There can be no angles or ridges.

Vacuum it all.

Acetone wash. Watch for grease.

When clean; apply thixo mixes to fill all low spots and make fillets and wetout the glass in place immediately.

 

Thanks for everything. Should I cap the stringers with CSM or 1708 after taping the sides with 1708.

 

1708

Generally you need a well laid 12 oz fabric to be waterproof.

 

Ideally you’d use 1708, but once you put the floor in place the floor takes the place of the top of the stringer in handling the load. This makes CSM a reasonable option.

That is if the floor is attached to the stringer.

 

By the way, what is the cleat you referred to fallguy?

 

A cleat is just a board or panel that allows a other panel to be fastened.

For your sole cutaway; you attach with epoxy thixo or epoxy and glass a cleat to allow your sole panel that was removed a new place to be glued.

Then if you are spanning say 20", you won't have a soft spot in the sole.

 

Apples to apples, I’d stick with polyester resin, it will outlast all of us, and will be compatible with existing.