85 Supra Comp with the Dreaded Stringer Rot!!

[MarbleFalls]

Previous Owner was basically giving away his boat because of the rotting deck in two places. The engine wouldn't start either which Ive already taken care of. 1738617387173881738917391

[MarbleFalls]

Didn't realize what I was getting myself into when pulling the deck. UGH .... Nasty water filled foam. Well, the clean up is behind me just trying to decide how far I'm taking the restoration in the middle of boating season. Decisions, Decisions 17392 17393173941739517396

[michael hunter]

There are only two kinds of pre 92 Supras . Those that have had stringers and those that need stringers.

[SquamInboards]

just trying to decide how far I'm taking the restoration in the middle of boating season

At this point you're way past the point of no return. Just dive in and do it right, you'll be glad you did. Or, if you really did get the boat for almost free, keep or sell all the best parts and cut your losses; look for a better one.

[MarbleFalls]

Strong consideration to sacrifice $200 in decking, PL and carpet to get 3-4 months of use out of the boat. One of the very few things which impresses me about the construction of the boat, the wood inside the stringer is completely rotted away, but the fiberglass form around the wood is hard as a rock. To cut them away seems counter intuitive to the strength it provides compared to weight/space it consumes.

[MarbleFalls]

There are only two kinds of pre 92 Supras . Those that have had stringers and those that need stringers.

So what changed after '92 in production/design?

[Jetlink]

So what changed after '92 in production/design?

They switched to all composite materials instead of wood for the stringer and floor composition.

[Hagman]

My 86 has the dreaded stringer rot. But the floor has no spots in it at this point. Three winters ago I asked my boat repair guy what I should do about securing my motor mounts. He said in his opinion the wood inside the fiberglass was a very little support. The fiberglass around the wood was where the strength was. But you need solid wood to bolt the motor to. My solution short-term was to mount to 2" x 4" x 0.25" angle iron to the inside of the stringers. I cleaned the metal thoroughly primed it with epoxy primer and glued the metal to the inside of the stringers with auto body epoxy. I also bolted the angle iron at six places just to hold them secure until the epoxy had cured. I then drilled and tapped and installed stainless steel bolts to secure the motor mounts. I'm now halfway through my third season the motor mounts are as strong as they were when I first install them. The floor still has no sign of any soft spots. Last winter I changed the carpet and expected to see some discoloration through the Fiberglas in the plywood at this point there is none. Crossing my fingers and really curious just how long this patch will last.
Strong consideration to sacrifice $200 in decking, PL and carpet to get 3-4 months of use out of the boat. One of the very few things which impresses me about the construction of the boat, the wood inside the stringer is completely rotted away, but the fiberglass form around the wood is hard as a rock. To cut them away seems counter intuitive to the strength it provides compared to weight/space it consumes.

[SquamInboards]

My solution short-term was to mount to 2" x 4" x 0.25" angle iron to the inside of the stringers. I cleaned the metal thoroughly primed it with epoxy primer and glued the metal to the inside of the stringers with auto body epoxy. I also bolted the angle iron at six places just to hold them secure until the epoxy had cured. I then drilled and tapped and installed stainless steel bolts to secure the motor mounts. I'm now halfway through my third season the motor mounts are as strong as they were when I first install them.

Interesting. I bought an '85 Supra Comp with this exact thing done to extend the life of the stringers, etc. - like, exactly the same - bolted in 6 places, drilled and tapped for the motor mounts. I don't know the condition of the floor when they put the metal brackets in, but it was so soft when I bought the boat that you could pretty easily put a hammer head through the floor with a moderate swing. I will say that the motor wasn't going anywhere though. It seems like a good short-term solution where most of the structure is fine. In hindsight, I should have kept those brackets.

However, I have seen a sterndrive boat that had rotten floors and stringers, that had a major fiberglass structural failure due to excessive flexing. Basically any older boat will twist a little every time it goes over a wave; in the case of this boat, one particularly hard impact on a big wave finally cracked it open. The way it cracked (facing forward), a big sheet peeled back and opened a nearly 2' x 2' hole in the bottom. Because of the foam and floor holding some water out, they were able to limp the boat to shore, although the nearest shore was steep and rocky. It was a scary day for those people with their young kids in the boat.

I guess all I'm saying is, be careful with partial repairs.

[michael hunter]

My pre stringer 84 comp twisted and wiggled terribly especially when in choppy water. after the stringers were done its like a rock probably better than it was originally.

[SquamInboards]

Working at a marina we put boats on stands all the time with one stand under each corner of the transom and blocks under the keel near the bow. After setting the boat down we'd give it the 'shake test' before taking the forklift out from under it, which was basically grabbing the gunwale near the windshield area and shoving the boat back and forth, up and down to be sure it was secure. Brand new boats wouldn't twist at all. A rotten boat, you could get several inches of twist without much effort. It's actually a pretty good way to test a boat's overall integrity, I wish it was more practical to do this as a pre-purchase inspection on older boats.