60's Fiberglass Floor Replacement

I am new to both this forum and working with fiberglass. I have a 14 foot v-hull boat built in the 60's, I think. There are no identification tags so there is no information on who the manufacturer is, and I am curious if anyone can tell from the photo. I am replacing the Transom and the floor, and I would like to know if the stringers should attach to the hull? I have read that they should not and I want to be sure.

 

If they are not attached to hull what would they be attached too. Let's see some inside pics. I don't recognized boat off hand but I have replace many a transom and rotten floor. You never know what your going to get until you start cutting. I have vibrating tool that lets me make surgical cuts in fiberglass decking or transom so that it can be put back with minimal of work. Many times work be done entirely from the inside.

 

The stringers were originally attached to the bulkheads only. I have pictures clearly showing they are not in contact with the Bow, and are held in place by having fiberglass molded over them in an arch. It is my understanding that this covering is what creates the strength, not the actual stringers. I would attach the photos but I don't see how to do that in my reply.

 

Dave, there are a couple of engineering approach used in this regard, one you've mentioned.

Typically, in the era of that boat's build, the stringers would be hard bonded to the hull shell, which would cause stress risers. To eliminate this issue, a soft bond is preformed at the contact point (where the bottom of the stringer touches the hull shell). This can be done several ways; a bedding compound, foam or other "pad" under the stringer.

Whichever approach you take, the stringer is still hard bonded to the hull shell, with fabric tabbing that goes completely around it and spreads out, onto neighboring hull shell. If the tabbing it heavy enough (thick enough) then the actually stringer is just a form, to lay the fabric over. If the tabbing is not thick enough, then the stringer is part of the structural assembly. Figuring out which you have is difficult without seeing it. What was the thickness of the tabbing holding the original stringers in place? Does this thickness rival the hull shell thickness or is it just a few layers of fabric?

If it's just a few layers of fabric (typical) then the stringer does impart considerable longitudinal stiffness to the hull shell. If on the other hand, the tabbing over the stringer is quite thick, then you can use your aunt Millie's mashed potato salad as a stringer core, tab over it (heavily again) and the stringer is just a form (mold) to properly shape the tabbing.

 

PAR,

Thanks for your wisdom, it is right on as far as I can tell. The stringers originally in my boat were not touching the floor, and there was a very thick mat of fiberglass formed over the stringers and bulk heads. I carefully cut out everything, and saved all the pieces. The bulkheads were definitely attached to the bow skin, but the stringers were just laid in and held in place by slots in the bulkheads.I have lots of pictures of how this was set up, but I don't know how to show them to you. If you can tell me how I can post them I would be more than happy to oblige, especially since it will help.