390 Express - Stringer Question

[Dr MicroChip]

As many of you know I am replacing the stringers alongside the water tank hold due to extensive rot.

See my restoration thread HERE

I noticed that the existing stringers have a 1/2" gap between the hull and stringer. I was wondering if anyone knows the reason for this? Does it allow the glass tabs that hold the stringers to the hull room to flex? I was planning on filling the space between the new stringers and hull with thickened epoxy but now I am not so sure. Comments please!

 

[jgoedd99]

I can't answer your question, but I am interested in what responses you get as I found something similar when I repaired two of the tabs on my swim platform this spring. There was a vertical crack in the tabbing that connects the horizontal rib of the swim platform to the vertical transom, on two of the swim platform supports. Once i ground off the old tabbing, i also found a 1/2 inch gap between the horizontal support member and the vertical transom. I was not sure what to make of it, but i did fill the gap with a thickened epoxy mixture before re-tabbing the horizontal support to the transom.

 

[oknoproblem]

From the description you gave of the fiberglass attaching the stringer to the hull, it does not seem logical that it would be "engineered" for flex.
In a previous life I worked in a boat manufacturing plant, they took great pains to scribe the stringers before the final fitting to match the variations in the hull, then filled in ANY void and created a small fillet with a thickened glass bead resin mix, then began the layup schedule to bond the stringers to the hull.
Flex was not something you wanted to see in a Gelcoat finish, in most cases the major contributor to spider cracks.
I would fill the void in as best I could, inject a suitable epoxy, or glass bead mixture with some sort of tubing as far back as you can. I would imagine that the underside of the stringer was exposed wood, so anything you can do to protect and reinforce the stringers the better.
Just my $.02 worth, oh and you are doing a great job with that renovation, keep up the good work.

 

[Dr MicroChip]

I agree. I will be filling in the void with rot stop epoxy. I temporarily epoxied in a standpipe through which I will pour in the epoxy. The stuf I use is thin and will soak up in to the stringer.



Here is what it looked like before:


See my current progress HERE

THANK YOU FOR YOUR COMMENTS!!