[JohnB]

I am currently running a tweaked 250 EFI Merc offshore, probalby about 310 hp. Lots of power, but 1.7-1.9 mpg is putting me in the poor house at 3 bucks a gallon. Long range plan is to put a Suzuki 4 stroke or Merc optimax 300 on her. Pick up a little speed and a lot of milage.

As for the coring, I drove my self nuts looking at all the options. The original core lasted through 20 years of abuse and poor installation from the factory, if this one goes 25, that will be fine with me. I went with Okumi marine plywood, and all the layup was done with epoxy, 4 layers of it. We have seen alot of transom failures in foam core boats (I won't name names). I think if they used epoxy instead of glass, they wouldn't have as many problems, just my opinion. I used dyvincell to recore my hatches, and the stuff has worked great.

For whatever reason, all the seacrafts I have seen that have one stringer bad, it's always on the port side, wierd. For you stringers, I would drill some 1/4" holes ever 12", right at the bottom of the stringer, and let it drain for a long time, maybe put some heat on it, I used hair dryers. Then plug the holes, knock some 1/2" holes in the top, and pour slightly thickend slow cure epoxy in to "reconnect" the cores to their outer skins, and then run some 45 degree bixal tape down the sides of the stringer to reinforce the stringer to hull connect, I used to layers of 9 oz/6" wide the whole length of the boat.

The cracks in that area are usually because the lower cap is now lose from the top of the stringers and is moving around. Most of them do that, especially when they have seen as much water as mine has.