How to questions about stringers

Shrek · #1 12-16-2011, 10:19 AM

I've read a ton of rebuild threads and lurked a bunch on classic seacraft, but I still have a few questions regarding the basics of stringers, how they work, and some of the myths that I've heard that I just cannot believe are fact. Can anyone answer the following:

1. Can a stringer be hollow and still do the job. If so, why fill the thing with AB foam? If the wood in my stringers is rotten but the lamination of the glass to the hull is good, is the problem critical or can the boat be used for another season?

2. I have heard that you need to bed the stringer or the core material in some type of bedding compound in order to prevent "hard spots." Is this true and if so, what the heck is a hard spot and why is it bad. How do I avoid this failure?

3. Can I pre-make glass stringer sections and just bond them to the hull or will doing this create hard spots? If I do it this way with pre-made sections of stringer, do I need to glass the inside of the pre-made section to the hull?

4. If I create a stringer grid, will that help the boat in terms of stiffness or do I risk more of the dreaded hard spots?

5. If I do go with the pre-made stringer sections which would be hollow when finished, do I need to glass some kind of wood firing strip to the tops of the stringers/grid system so that I have something to screw the deck to?

As always, thanks in advance.

smokeonthewater · #2 12-16-2011, 12:18 PM

Quote:

Originally Posted by Shrek

I've read a ton of rebuild threads and lurked a bunch on classic seacraft, but I still have a few questions regarding the basics of stringers, how they work, and some of the myths that I've heard that I just cannot believe are fact. Can anyone answer the following:

1. Can a stringer be hollow and still do the job. If so, why fill the thing with AB foam? If the wood in my stringers is rotten but the lamination of the glass to the hull is good, is the problem critical or can the boat be used for another season?

depends... if the casing is rigid enough to support the load then yes..... the foam is a form to glass around and support the glass till it sets up....... Again, depends but yes, most likely a wood cored stringer needs the wood

2. I have heard that you need to bed the stringer or the core material in some type of bedding compound in order to prevent "hard spots." Is this true and if so, what the heck is a hard spot and why is it bad. How do I avoid this failure?

the shape of the stringer needs to perfectly match the hull to evenly support it..... this is not generally practical so the "bedding matches the stringer to the hull"... a "hard spot" vs a soft spot refers to a small spot that carried too much load because other areas are not supported....... avoid it by bedding

3. Can I pre-make glass stringer sections and just bond them to the hull or will doing this create hard spots? If I do it this way with pre-made sections of stringer, do I need to glass the inside of the pre-made section to the hull?

would be 10 times the work and would not be practical..... yes it would need to be glassed down

4. If I create a stringer grid, will that help the boat in terms of stiffness or do I risk more of the dreaded hard spots?

stringers don't form grids.... they only run lengthwise... ribs run crosswise...... solid ribs, stringers, and sole will help stiffness but I'd look into the cap and gunwales...... tie the cap to the sole with sheer panels and she'll stiffen up

5. If I do go with the pre-made stringer sections which would be hollow when finished, do I need to glass some kind of wood firing strip to the tops of the stringers/grid system so that I have something to screw the deck to?

no

As always, thanks in advance.

hope this helps

Kracker Jack · #3 12-16-2011, 07:56 PM

Shrek I also have been following that 17' Pacemaker build on THT. He does have a pretty cool fab system for making those hollow stringers. When I saw his stringers I wondered the same thing about putting some type of wood on top of the stringers to attach the sole to, I guess all you depend on then is the glue or putty.

smokeonthewater · #4 12-17-2011, 05:34 AM

you can drill and screw right into the glass.... very strong holding power

Shrek · #5 12-20-2011, 05:09 AM

Quote:

Originally Posted by smokeonthewater

you can drill and screw right into the glass.... very strong holding power

Enough for my t-top?

smokeonthewater · #6 12-20-2011, 10:19 AM

that depends on how thick you make em.... but yes, plenty strong....

RidgeRunner · #7 12-21-2011, 07:29 AM

The T-top attaches to the deck so the deck should be attached pretty well to the top of the stringers. Screwed and glued or glassed if practical.
I know of boats where the stringers are shot and they just keep going. Really depends on the vessel and its construction. How safe is it?? Who knows til it goes south.