1974 Aquasport 19'6 - Transom is cracking, needs reinforcing

[Rockport Aquasport]

Hello everyone and Thanks in Advance as always - this site is great!!

The 19'6" is from 1974 and it has a new Yamaha 150 SHO on it after the rebuild we did in 2021 - the boat shop that did our rebuild recommended that and put it on.  Love the motor but think, in retrospect, that it was too much weight for the transom which has not been modified or reinforced.  Scuppers sit below the waterline as many other posts that I read on here have noted.

Well, we took it in for a quote to reinforce it and this is very expensive to do, more than I would like to put into the boat. 
- Fiberglass reinforcement was ~$5000.  (No way I can handle that by myself, fyi)
- Aluminum plate run across the interior side of the transom and tying into the corners of the transom which they tell me have additional support in them.  The idea is that this will distribute the weight and thrust forces across the whole transom and not just to the center.  This option was $2000 as the plate itself is ~$800 plus lifting the motor, tying it in and re-glassing the corners, and putting motor back on.

Does anyone else have any suggestions for a cheaper solution that we could implement that would reinforce the transom??  Perhaps brackets that could tie into an area that has support - floor, sides, etc...  Any and all thoughts appreciated!!

[Duffy1470]

Sell the motor and get a lighter one.
Or
You could do the work yourself. If it's the original configuration you could tie the stringers into the stern which they are not originally.. that would probably do it

[RickK]

Where is the transom cracking? A typical crack runs along the top edge of the transom on the outside of the transom. We see this a lot and it is actually the liner that covers the inside of the transom and comes up and over to the outer edge. It cracks along where they glued the liner to the transom top. And this crack doesn't seem to compromise the transom unless it lets water into the transom.
Have you done a bounce test on the transom? Tilt motor up, lay your body on the center section of the lower unit. Bounce up and down on the engine watching the transom. If it doesn't flex, the crack could be cosmetic and you can use caulking to seal it up

[Rockport Aquasport]

Thank you for the great replies.

First, the cracks are occurring in the corners of the transom where it meets the hull side walls.  Mostly, where the lower part of the transom rises and then ties into the full height corners.  Worse on the port side than the starboard side.

Second, if I attempt to tie it into the stringers is there a way to do that straight through the decking??  I am trying to avoid ripping up the decking which will then need to be re-glassed.  Locating the stringers through the fiberglass deck could be hit or miss, I am guessing or is there a trick to locate them and drill into them and then seal that off?

Thank you as always!! 

[Duffy1470]

I cannot imagine a way to do it without removing a section of deck. Not a good way, any way.

[RickK]

You can pour a composite transom. Use a chainsaw, come in from the top and dig out the old coring.