Stringer question

[AK_Chappy]

Ok,<br />After I pulled the old rotten floor out of my boat, I discovered that it had styrofoam for flotation, and the stringers were basically very thin fiberglass with old plywood glassed across the top.<br />I would like to put in a solid stringer instead. What type of wood and what sizes, widths, should I get? The middle stringer was originally 4" wide at the bottom and 2 3/4" wide at the top.<br />The two outside stringers were 2 1/2" at the bottom and 1 3/4" at the top and the ones between them are 2 1/4" wide. Here are some pictures that might help you visualize all this.<br /><br />

<br /><br />and <br /><br />

<br /><br />Thanks in advance for all the advice <br /><br />Chappy

 

[Chris1956]

Re: Stringer question

Chappy, You are asking us to engineer the design of the supports for the boat. Difficult for me to do. If the original stringers are intact, I would reuse them, with maybe some added 1 by lumber to add additional strength. Then you can refoam and glass a new 1/2" plywood floor over them. I<br /><br />f they are not intact, you will need to use wood strong enough to perform. I think you should use pressure treated pine, in 2 by widths (single 2x6 or 2X8)for the outer stringers. Make sure it it as dry as possible. You can use stainless steel screws to attach it to the original stringers, then glass it to 'em as well. I guess you will need a 4 by (two 2X6s, 2X8s)stringer for the center (keel). Glass them in as well. Foam it all and then use SS Screws to attach the new plywood floor to the stringers and the gunwales, and cover the new floor with at least two layers of glass (run it up the gunwales several inches) and plenty of resin.

 

[quantumleap]

Re: Stringer question

Are they hollow in the middle under the board or solid glass with ply on top? Very unusual design, but looks clean and functional. Any chance that this could be someone else's rebuild work or does it appear original?

 

[AK_Chappy]

Re: Stringer question

The original wood in the stringers are completely rotted out. The only wood appears to have been the top layer of plywood. They are hollow underneath that.<br />Chris,<br />I am glad to hear that I wasn't way off the mark. I was thinking of using 2 2X6's trimmed down to 4" tall. I need to do this because the floor will be 4" off the bottom and a 2X4 is not actually 4" tall or wide, depending on your point of view.<br />If I glass them in solid with no drain in the middle am I asking for trouble? I would think any water will run down to the back, w/ nose up of course, and as long as the drains are set up I should be good to go. <br />Quantum,<br />They appear to be original. This boat has seen a general lack of care for close more than 30 years, or so it appears. I think if fiberglass could rot, this whole boat would've fallen apart a long time ago.<br /><br />Thanks for all the advice,<br />Chappy

 

[JGREGORY]

Re: Stringer question

AK I asked Jasonj that same question once and the answer was the same for everybody else also use 3/4 ply as the stringer. Because of the way it's made there is more strength and it will not have a tendency to warp as much from what I've heard.

 

[JasonJ]

Re: Stringer question

I am a fan of ply, but you could use whatever, as long as it is sealed very well. I think most of the rot we have all experienced was 10 percent design flaw and 90 percent lack of care. Most of the projects that show up here are between 20 and 30+ year old boats that have been poorly cared for. I can't even count how many times I have heard "its a boat, it can sit in the rain". Yeah, we have seen where that gets us. A cover does a world of good, so as long as you rebuild it right and take care of it, you be set. Good luck....

 

[quantumleap]

Re: Stringer question

If the underneath hollow channel is intact with no cracks, I would just grind off the top and replace the ply as it came from the factory. Having no wood in contact with the bottom would be nice. You could add a couple layers of mat overlaping each stringer assembly to the floor for extra strength. It would be stronger than new and alot less work than starting with a bare hull.

 

[dmenbiker]

Re: Stringer question

Chappy, You've got a great start on your project. <br />I'd shy away from wood stringers for 3 reasons. <br />First is weight. Second is they will rot sooner or later. Third, is unless you install them correctly, you can crack the hull or cause delamination during trailering or rough water.<br />I would suggest using foam. Rough cut to shape and stick where you want with marine "bondo". Sand to shape, overlay with glass. <br />It appears you already have a well engineered hull. Good luck and have fun!! Dave<br />P.S. IF there was wood in the original stringers, it was only there as a mold and not strength.

 

[SCO]

Re: Stringer question

Was there wood in those stringers originally? Unless the fiberglass sides are relatively thick, they appear to be mere sheaths for the wood stringers with a plywood floor or spacers for a floor on top? I wood was in them I would cut off the fiberglass tops only, refill with treated planks, then epoxy resin/ glass over the sides and tops. If there was no wood in the stringers originally, I would redo it the way it was designed to keep weight down, maybe add a new layer of epoxy glass. If designed wo stringers, maybe the hull is thin and would not work well with wood stringers flush with the hull surface