where are my stringers?

[68C15]

1965 Johnson 17' runabout
I am getting along pretty far with my rebuild. I replaced the plywood using foam board as a template (great idea guys, thanks) and I am now in the process of upgrading the horizontal beam. it was a plain run of the mill dimensional lumber 2x6 with a 2" x 4" angle iron in the center. I am going with a 2x10 LVL (laminated veneer lumber, think thick plywood) and want to run vertical supports from the beam to the stringers. I am using PL premium adhesive as I heard this stuff is super strong. I am also improving on the original design by covering the whole front of the plywood with glass and using glass to tie the beam and supports to the sides and floor/stringers.
what I need to know is where the stringers are located. I was thinking of 4 supports, 2 on the stringers and an additional 2 somewhere else. I was also thinking of fabricating some sort of knee brace in the motor well coming from the bolt holes down to a couple supports. these will be made of either steel or aluminum. any feedback guys?
I hope the pics are helpful, I am far from being a competent photographer.

 

[cheesegrits]

Re: where are my stringers?

I think the "horizontal" beams are your stringers. I have never seen metal on them like that. Probably a add on. My question is what condition is the rest of the transom? Are the outer edges like the middle? If they are you need to replace the whole thing. Also anytime you replace stringers you need to brace the hull so it doesn't flex or warp. Try to post some pics looking across the whole floor so we can see the actual setup of bracing.

 

[68C15]

Re: where are my stringers?

the horizontal beam is located half way between the top and bottom of the transom and reaches from side to side. I too believe the steel is add-on.
I replaced the complete transom from gunwhale to gunwhale (I think that's what the sides are called) using 2 layers of 1/2". I placed the joints far apart and well away from the motor mounts. it is also PL'd to the sides.

weather permitting I will post some pics today of my upgraded beam and of the floor from front looking back.

 

[PiratePast40]

Re: where are my stringers?

68C15 - You said that you're using PL as an adhesive. Be careful about where you use it and the thickness. PL shrinks as it cures and leaves voids in the middle as well as causing bubbles on the surface. Cure time can be up to a week before you can grind it down and apply resin. In many cases, you're really not saving much by using PL instead of mixing up your own filler.

It's OK to use as bedding - just be aware of the limitations.

 

[68C15]

Re: where are my stringers?

68C15 - You said that you're using PL as an adhesive. Be careful about where you use it and the thickness. PL shrinks as it cures and leaves voids in the middle as well as causing bubbles on the surface. Cure time can be up to a week before you can grind it down and apply resin. In many cases, you're really not saving much by using PL instead of mixing up your own filler.

It's OK to use as bedding - just be aware of the limitations.

"mix up your own filler"? could you please elaborate?

 

[oops!]

Re: where are my stringers?

"mix up your own filler"? could you please elaborate?

i used pl and it bedded fine....but heed the advice of beware of its limitations....

the filler our friend was referring to (i beleive) is called peanut butter....

just do a search.....or check in the hull extension thread,,,,the index is on the first page, and there are direstions and ingredants for it........there are several mixtures for differnt purposes....

check oops super dooper peanut butter.

cheers'
oops

 

[PiratePast40]

Re: where are my stringers?

LOL - you just heard from one of the experts. Yes - "peanut butter" is one of the terms used for filler material. It's a mixture of resin and glass fibers or other material. Since resin itself has little to no strength, you need something else to add strength and ridgidity. You can mix up your own - peanut butter is a great example. or you can buy premixed filler. Bondo makes a poly resin mixture in either short or long strand versions that you can buy at most automotive supply stores.

The whole point was that construction adhesives, like PL, can certainly be used. Just be careful that you don't try to use it for the wrong purpose.

I'm afraid that I'm one of those that tried to use it as filler and ended up grinding out and correcting my own work :redface:

 

[68C15]

Re: where are my stringers?

heading over to check oops's thread now. I've heard of doing the glass fiber/resin thing but I wasn't sure it was a good idea. if you guys say it is then...