Stringer Bedding

[RickR]

I am getting ready to install new stringers on "The Boss's " boat.
http://www.boatdesign.net/forums/showthread.php?t=20668

West Systems says to bed the stringers in a thickened epoxy/cab-o-sil mixture (thickness of peanut butter) Westsystems.com

This guy says do not bed the stringers, leave a gap.
http://www.yachtsurvey.com/HullFailP2.htm

Anyone have an opinion?
THANKS!
Happy Holidays!

[gcarter]

Rick, I agree with everything, including the article. The article is exactly right about the stress cracks (or lines...just see my thread) because of the hard points. The good thing thing about the thickened epoxy is it stays flexible. After curing, it has, I would say a 80 durometer hardness. There's plenty of give. Another thing is to spread out the load. I need to post some more pictures, but I'm not quite ready. The base of my stringer bottom tangeants are now about 4" from tangeant to tangeant, with considerable layup on top of the stringer/bottom joint.
IMHO follow the advice of the thickened epoxy and you'll be accomplishing the "spirit" of the article.

[Jamesbon]

You have a nice project going there! I don't admire you now, but will when that TS6M is finished. I'm sure it will be the nicest one on the water!

I grew up in these boats on Lake Anna VA. Used to have a yellow TS6M about 8 years ago. I still miss the distinct sound they made.

Good luck on this one, keep us posted on your progress from time to time.

[MOP]

My 2 cents being an old out of date USAF trained glass man! In the industry it is well known that butting bulk heads and stringers hard to the mating surface creates a hard spot that does cause fracturing. I have replaced rotted bulk heads in boats where I have found nylon rope between the wood and the hull sides to alleviate the hard spot issue. The boats I worked on were much larger and far more expensive, that may show of some extra care taken. I was alway careful to duplicate the builders work as close as possible. Now the flip side, I brought up the hard spot issue with my friend that was the head glass guy at Hustler Boats who also did the transom & stringers on my boat. Hustler having many boats that did over 100 had always isolated the stringers but still have issues with hull cracking at the stringers, they went to a paste with linear fibers which cured the problem. I do not remember the manufacturer but I would imagine a supplier could get it for you. I am not sure about using the thickened Epoxy/cab-o-sil mixture, it may well do the job but I would check into the proper bedding material or isolate.

A-P.S. My stringer job is 3 years old and has seen a fair bit of rough water, my bays, Long Island Sound and the Atlantic my bottom show of no stress marks what soever. Those that have run with me know I like to get on top of the rough stuff!

Phil

[hardcrab]

MOP -
do you suppose 100% silicone would be acceptable as bedding ?
Would that cure to be to dense ?

[MOP]

MOP -
do you suppose 100% silicone would be acceptable as bedding ?
Would that cure to be to dense ?

I think it is too elastic to do anything, might just as well leave the gap or use a more dense mixture. The cracking from the hard spot can be taken care of by a little more layer of glass brought out from the bases to as George pointed out spread the load. Some boats are glassed with just enough to hold the parts together, not enough to make them structurally sound in the longer term.

Phil

[RickR]

THANKS for the replies!
The Supra is built with Kevlar and a thin core so I decided to rebuild the stringers the way they were originally, beveled and bedded w/cab-o-sil. Also I upgraded by using a fillet 1708 and epoxy.
1st stringer is in:smash: on to #2:bonk:
Nate
The 22 is such a handfull with the poor idle:wink: the Spura is going to be "The Girls" boat for "The Boss" to play with. I am going to add a set of inline mufflers along with the Super Traps and mabe even a crossover.
We are looking forward to a low profile, regular fuel, quiet, slow boat to use on our "Off" days.:boat:
JEEZ, I must be getting OLD.

BTW I needed a quick answer to the stringer bedding question so I posted here. I'll put future updates in the "Other Boats " Forum