Second Stringer question

I have been reading up on stringer repplacement. I have found several refernces to keeping the stringers off of the hull bottom. Can someone please expalin this fully? I have always thought that the stringers shloud be butted to the entire legnth on the hull bottom and bonded the entire legnth.

Should I NOT do this? I am laying three stringers on Monday. Should I shim them up 1/32 to 1/4 inch? Then glass them in with matt then woven roving? Could I possibly possibly foam under them? The Have to touch the hull somwhere, it seems like they would just get rattled loose and flop up and down, inside of a fiberglass shell, if they were not bonded to the hull.

 

Thanks.

 

You're welcome


Seriously, though, I read this thread and subscribed to it because I figured someone might answer you.

But, the thing is, I know this question has been answered before, and I am quite certain that if you did a search you would get an answer.

Regards,

Andre

 

I've done a search for stringer replacement and haven't found a solid answer to this question. What type and size of material, if any, should be placed under the stringers?

 

Shimming of stringers

As I read from Corpus Skipper somewhere, "OK, I'll bite".


The simple answer is that there is no simple answer. It depends on what material you are using for your stinger, wood, foam or what. Do you intend to just tab in the wood and let it do the work? Or are you going to competely encapulate the stringer with glass? (better)

As I understand the concept, the goal is to avoid the sharp corner that the stringer - hull intersection makes, especially on its outboard edge. This sharp corner may invite cracks. To minimize this, one method is to create a shim under the stringer. The cross sectional shape of this shim is trapazoidal, like a tringle with the top cut off parallel to the base. The width of this top is the same width as the stringer and the bottom is wider by some amount. Now glass the whole thing to the hull. Easy at the stern, but it may be more diffcult as the deadrise angle of the hull comes into play at the bow.

An easier and no less structurally sound method is to shape the bottom of the stringer to conform to the surface of the hull as best you can. Build a simple fixture to hold the stringers in position. Tab the stringers into the hull in several places with 4" wide fiberglass, just enough to hold them in position. After the resin kicks remove your fixture. Using a light weight putty, create a filet on the outboard bottom of the stingers where they meet the hull. After it kicks, sand off any rough edges.

Cut your fiberglass to drape over the stingers and extend onto the hull either side 6"-8". If you intend to use more than one layer be sure to stagger the edges to avoid abrupt changes in thickness. Glass the whole mess in.

Voila!

djs

 

Thanks, I think I understand better now.

I haven't pulled out the whole floor yet. From what I can tell, the originals were wood stringers encapsulated in fiberglass. I planned on using the same method.

 

Support the hull

Once again I'll say it, support the hull well so that when the stringers are removed it doesn't loose its shape.

Consider removing and replacing them one at a time to help avoid hull distortion.

Good luck

djs