Stringer Questions

[pete44]

Been struggling with this issue...Trying to install new stringers (only 2) in my 87 SeaRay Seville Bowrider..Having a heck of a time to get new stringer to meet to hull evenly..(tried the cardboard/string trick) come to find out on an 8 foot section of board layed flat on my hull there are 1/4 inch up to 1/2 inch gaps from board to hull....only way I see to get a uniform gap is cut stringer in smaller sections...I know I may be wrong but this is getting ridiculous .... Last issue is I've read to leave a 1/4" gap between stringer but have also read from a 30 year veteran boat builder he has NEVER seen a "gap" between stringer and hull...They are against one another for overall hull strength...I wish I had the way SeaRay did it originally..My stringers were toast and I could not tell....Thanks for help!

Pete

 

[tdrudd87]

Re: Stringer Questions

Got any pictures? It may make it easier to see what you are fighting. I would keep at it, trying to get a better fit.

As far as a gap, I have heard of that, but it doesnt seem like the best solution. I would bed in PL or pb. Check out my thread and many others and feel free to ask any questions!

Terry

 

[Robert4Winns]

Re: Stringer Questions

When I removed my stringers, the part that was not rotten was not touching the hull. There was about 1/8 to 3/16 space under the stringer. It looked like there was some sort of caulk used to hold the stringer up off of the hull, but only a few blobs, not the entire length.

As for scribing the stringers I was struggling with how to do it as well. I decided to install my center bulkheads first, the plywood pieces that separated the ski locker from the fuel tank and the fuel tank from the engine. I just bedded them in with PL. Then I had a place to clamp the stringer. I cut the stringers to the approximate shape and clamped them against the bulkheads, with the top about 1.5 inches higher than where it needed to end up. Then I went along the length on each side of the stringer and drew a line a little more than 1.5 from the hull. I used a 4" cutoff wheel with the pencil in the center to follow the hull and mark the stringers. After cutting I clamped the stringers again, this time at the correct height, or as far down as it would go. I used a popsicle stick as a feeler gauge under the stringer and marked where I needed to cut off a little more. It took a few test fittings but I ended up with a pretty even gap under the stringers, which will allow for the PL that I will use to bed them in. I hope this description helps. I will try to post some photos on my thread soon.

 

[ondarvr]

Re: Stringer Questions

Don't stress over it being 1/4", it really doesn't matter the exact amount, the goal is to not have the plywood only touch in a few spots, it could be 1" the whole way and not be a problem.

1/4" is just easy to fill and work with, so just do the best you can.

In production on small boats stringers are frequently just set in place with no effort made to have any gap and for the most part its not an issue, as boats get bigger it becomes more common to space them off the hull.

 

[Greg Mrozinski]

Re: Stringer Questions

Pete,

I agree with ondarvr. Having a gap is not a big deal really since the strength really comes from the glass you will installing after they are set. I had multiple gaps under mine when I installed my stringers. I just loaded up on the PL, squeezed them down in, and removed the excess. I think the key is to get the right height so the floor makes solid contact with the tops of the stringers. Bottomline is that any quality work you are doing now will probably exceed the original installation and last longer.

 

[pete44]

Re: Stringer Questions

In production on small boats stringers are frequently just set in place with no effort made to have any gap and for the most part its not an issue, as boats get bigger it becomes more common to space them off the hull.

Ondarvr,

Interesting comment...I have a 17 foot (actually 16' 9" boat) deep V-hull design...I have lots of pics BUT none about stringer layout..I'll see what I can do about that...I don't know if my boat classifies as a "Big Boat"..So you would assume to leave no gap on stringer hull..My hull has a "little flex" to it ..Would'nt that act like a "shock absorber" weather the stringer had no gap or not..Sorry to be so deep in this BUT I want it right and no future damage to hull after the fact...Thanks,Pete

 

[ondarvr]

Re: Stringer Questions

Small boats would be under around 21'.


Leaving a gap is better, its just that many are made with no concern for one and its not a huge issue.

If the plywood is tight up against the hull it "may" create a hard point, it doesn't mean it will, but since you have the option, leave a space. The hard point won't flex with the hull and its possible for the gel coat to crack due to this. Don't be concerned that its exactly 1/4", just that it doesn't touch. The glass is carrying the load and will be able to flex along with the hull slightly if needed.