Transom extension and less stress, possible???

[dhaglund]

I've been out using the transom extender a couple of times now. The extender itself seems to work just fine. No apparent flex or anything.

The tricky part turns out the be what height to extend to. My transom extender adds 140 mm to the transom which is a bit more that the normal 5-inch (127 mm) difference between a short shaft and long shaft. Still this was not enough. 155 - 160 mm would have been better.

[dhaglund]

Well, it's been a while now, and since this thread was mentioned in a newer thread I though I should follow up on this transom extender

While the transom extender worked pretty well for the light Tohatsu M18 to begin with, I have since abandoned the idea. Even though the transom extender seemed very sturdy initially it wasn't up to the task of of taking on a Tohastu MFS25B which is a heavy lump. Even though I went back to the M18 later on the extender was bent and flexing, the transom had vertical cracks and whole transom was now slightly banana shaped.

It isn't all that easy to build a transom extender that will take up the force in all directions. I think it will require vertical reinforcement on the back and horizontal reinforcement on the front, or something like that. My extender didn't have a horizontal brace which later caused the vertical cracks in the wooden transom.

Then there is the issue of having a longer leg on the outboard. This is only an issue for portable engines. Event though I'm tall I find it much harder to lift a long shaft outboard than a short shaft just because I have to lift it higher up.

So, after all this, I would strongly advise against building a transom extender for a short shaft boat for portable use. It is doable. But it's just not worth it.