transom reinforcement?

[rpludwig]

I've asked this b4, but just getting around to it...
Switching from 4.5 hp merc 2 stroke, to 6 hp Tohatsu 4 stroke. Heavier motor, want to reinforce transom motor mount bracket with backing plate inside to distribute the load. Looking for something quik/eze, I see 304 SS plate 3/16 x 12 x 12 at Graingers for $67...adequate enough? (don't necessarily want to use plywood, epoxy it, etc.)
Thoughts?

 

[Gene Neill]

Your guess is as good as mine, bro-chacho. I would definitely say probably.

Just a thought, if you're interested in alternatives: McMaster-Carr offers structural-grade FRP sheeting pretty cheaply. 12" x 12" x 1/2" would run you $32.49. https://www.mcmaster.com/structural-fiberglass-(frp)

 

[JimInPB]

I would be more likely to use a 12 x 12 x 1/4" piece of G10 or FR4 fiberglass plate for about the same price -
https://www.eplastics.com/sheets/micarta/g10-fr4?page=2

...but yes, 3/16 x 12 x 12 304 should be enough.

Edit: Geeze, Gene beat me to it while I was typing.
McMaster's price are much better than the source I quoted.
Thank you Gene

 

[LakeShark]

I went to a local welding and metal supply shop and made mine out of some bent aluminum 1/4" for around $20.

If you want stainless why not just go through CD? It's cheaper and pre drilled. There is no need to reinforce the center portion but just where the bolts are.

https://www.catalinadirect.com/shop...tor-mounts/motor-mount-transom-backing-rails/

 

[Leeward Rail]

FWIW: Our 87 had a 15hp mercury 2 stroke on it, with big stainless washers. It appeared ok when I switched to the lighter tohatsu 6hp 4 stroke. I will eventually reinforce it but I don't see it as a priority. I visually inspect it, like the rest of the boat, regularly.

 

[Benny17441]

Surprisingly that 4.5 Merc 2 strokes weighs 45 lbs, I thought it be much lighter. The Tohatsu 6 HP 4 stroke weighs 55 lbs. A difference of 10 lbs. is not going to be significant. You may add larger washers to the bolts in back of the transom.

 

[pclarksurf]

I went relatively simple-- inherited two sticks to support my Honda 4 stroke. Wasn't pleased with the lack of support and added the ply. No complaints and relatively inexpensive minus the epoxy bath and marine ply:

 

[Hardhead]

Man -- that's some great access compared to the post 86' boats. To get back to that area in mine, it's like going headfirst into a coal mine. Looks good-

 

[rpludwig]

Man -- that's some great access compared to the post 86' boats. To get back to that area in mine, it's like going headfirst into a coal mine. Looks good-

It is great access (for gas fumes too, LOL)

Well, after all the great input on transom reinforcement, I'm rolling the dice with some big a$$ SS fender washers, lock nutz and some 4200....will report back if the transom falls off...hey, it's just a boat...

Cheers, hope y'all are on the water! & Happy MM Day, Semper Fi!