Re: best repair option for my 87 bayliner transom stress cracks
Make sure you are using a transom saver to support the engine while towing. They cradle the leg of the outboard, removing the load of the tilted engine from the transom and transferring the load of the raised engine to the rear crossmember of the trailer. This is crucial to any transom for towing because when you bounce the boat trailer combination over road bumps without the transom saver, the tilt wobbling of the engine goes to the transom and it's a terrible unnecessary thing to do to the transom. If you are already using one, ignore this.
Also, any prediction of how long a questionable transom will last must be accompanied by a disclaimer that it can only be a guess, and it could fail on the next outing. It could also never fail in the next 10 years, so simply stated, "Use it at your OWN RISK." Having said that, I used mine at my own risk knowing it was rotten with bad core samples for 4 years in the North Pacific Ocean and gutted all of the rot out this winter. It is a 15 foot tri hull with an 85 chrysler on it, with no stress cracks. I estimate that even with the rot it had, it could have supported that engine's operation for another several seasons because of the strength I found in it. However, the fix and waterproofing, high quality materials and methods used in these forums, all of which I am using, are going to make this season and following seasons much more enjoyable with the confidence that goes along with the quality of what I'm doing. The workmanship and methods used on these boats back when they were made were simply horrible, as were many things made during the seventies and eighties.
I attribute the problems we are dealing with to the 70's drug culture prevalent back then without drug testing. I know this because I worked for a gas turbine aircraft engine manufacturer in engineering back then and some of the engineering staff were party animals in every sense of the word, no holes barred. The results in that industry were there to be seen in many products in aviation, boating and automotive industries. The results of the decisions made back then gave us junk like the Ford Pinto and many other horrors of the era we all can remember, like some of the terrible movies that came out back then. So we got boats with internal foam filled bilges without waterproofing and all of them have rotten interiors. We got trihulls, of which I have grown to like very much after owning one, but still they were a thing of the era owing their prevalence back then to who knows what affecting the brains of those who decided they were the way to go, in combination with the brains of those who decided they were the thing to buy. The seventies were a strange time. The thinking back then was just to get them made and out the door, sold. Extreme popout boat manufacturing, popping them out, klanking them out, kerchunk kerchunk kerchunk ad infinitum.
These boats are still a great thing to get ahold of cheap and restore though, aren't they?