Deep Hull Cracks under Stringer

[saltwaterbluefish]

I want to start by saying thanks to all those who have posted on this forum it really helps a new guy.

I currently am starting to restore my grandfathers 1972 19ft Scat Craft. To this point I have got the hull supported, all the rotten stringers out, and started to sand when I ran into a few problems that I wanted an opinion other than mine on how to fix. Better to ask and do it right, then do it wrong and spend more money.

1st problem is under the stringer that runs the length of the keel there are some deep cracks. I did pour acetone into the cracks to see if it went thru the hull, but it didn?t seem like there was a leak. I am sure this is structural and was hoping for some guidance on how to fix.

2nd problem/question is can you lay down a layer of fiberglass in the inside of the hull before putting in stringers? I know it will add weight, but will it help to strengthen the hull and fill in any small holes you missed during grinding?

The pictures show what was left of the stringer layout before grinding, and then a picture of the deep cracks. There are about 3 different sections of those deep cracks. I am planning on using epoxy from US composites, and 1708 biaxial for the wood stringers but have been holding off on ordering until I know what I need exactly to fix the problem.

I appreciate any advice or help you can provide me.

 

[ondarvr]

Re: Deep Hull Cracks under Stringer

The cracks are from sloppy workmanship, they allowed resin to puddle in the keel, resin by itself is weak and brittle and will crack easily.
Grind out the cracked resin before doing any repairs.

You don't need to use 1708 with epoxy, use 1700, the "08" on the end is mat, and mat is not needed with epoxy. You really don't need to use epoxy either, but that's up to you.

 

[saltwaterbluefish]

Re: Deep Hull Cracks under Stringer

Will 2-3 layers of 1700 work for the stringers and the deck or would you select a different combination?

 

[ondarvr]

Re: Deep Hull Cracks under Stringer

You only need to rebuild to what it was when new, extra may feel good, but is of no real value (this is of course is if the only issue was rotten wood). 1700 and epoxy is far stronger that what was there when new, so two layers would likely be fine.