Inner transom plate curved?

[sogood]

Ever since I took the inner transom plate off during the strip down as part of my transom replacement, I had the suspicion that the plate was curved. It just looked a bit "off". I didn't investigate it too much as I was sufficiently distracted replacing the transom, stringers and engine mounts, but now as re-assembly draws nearer, I took a closer look at the transom plate, and it is definitely curved, or at least, not particularly flat.

I would imagine that it should be flat where it sits against the transom, given that the transom is flat. Is it possible that it was pulled out of shape over time, if the transom flexed? Having said that, the outer transom assembly sat flat against the transom, with no disfigurement. Could my transom have swelled or expanded/distorted on the inside only?

And how can I bolt the inner plate down now, without the risk of breaking it in half? Attached picture for clarity, where you can see the plate out of true on the left hand side. This is the bottom edge of the plate. Any thoughts welcome.

 

[Chris51280]

the transom soaked up water and swelled up. You should be ok tightening it back down

 

[sogood]

Thanks for that. I'm just concerned as the plate seems to be an alloy of sorts. Isn't there any danger that it could snap across its' width as I tighten it down?

 

[Rick Stephens]

I think the torque on the housing to plate bolts and studs is only 25 ft pounds. You are't going to break the plate staying in the neighborhood of proper torque.

 

[tank1949]

I replaced mine with new inner plates which were not perfectly flat either. The Gimbal housing should be flat but not all transoms are perfectly flat. I believe MC allows 1/8" out on transom outer surface and 1/8" out of inner transom surface being parallel to outer. You should Google specs. and follow religiously! I hope that you didn't use wood near through-hull drain plug opening. That is usually where water leaches into the wood and eventually set up rot. I used epoxy/fiberglass matt. Good luck!

 

[Bondo]

Thanks for that. I'm just concerned as the plate seems to be an alloy of sorts. Isn't there any danger that it could snap across its' width as I tighten it down?

Ayuh,..... That Is a possibility,..... It's cast aluminum, 'n aluminum don't like to bend twice,......

I'd put in the oven for an hour, at 450*/ 500* to anneal it alittle bit,......

Then install it, tightenin' the center, 'n top bolts/ studs 1st,.....
tighten the bottom last, 'n hopefully, it'll bend back into shape,.......

Or,......
Anneal it, 'n pre-straighten it on a press,......
If it snaps, replace it, or weld it back together,.... flat,.....

 

[AKJohne]

I put a 97 gen II in a different boat than it came out of it and the inner plate was not flat either, its been a awhile but it had a bow similar to yours, its pretty thin and it will flex, I suspect it will bolt up and flatten out just fine. Aluminum anneals but its a process and heating it in a oven at 450-500 is not going to do it. I would bolt it in starting form the middle and working out, seems there is a sequence in the manual for torquing it down. Check for cracks once its tighten down and periodically after that. If its doesn't crack when you install it then...... I think you will be golden.. Just one mans opinion based on my limited experience

 

[sogood]

Many thanks for all the responses guys. Feeling a bit happier now. Just waiting for a weather window to get the last of the glass work done, then it's reassembly time. I'll keep you posted in my thread that covers the transom replacement. Thanks again