Thickness of transom for small clamp on outboards?

[zeke67]

I've got '56 15HP and '74 25HP Johnsons and my 12 foot tin Crestliner needs a new transom board and clamp board. Both the motors and the boat are not accessible right now (they are in MN, I'm in TX). There is a transom board on the outside of the aluminum transom, and of course the clamp board is on the inside. For the clamp board I've laminated 2x3/4" pieces of plywood. Using 1/2" ply on the outside of the hull yields just over 2" including the thickness of the aluminum.

Pretty sure this will be okay, can anyone confirm?

I've already epoxied a 3/4" ply for the outside board, which would yield just over 2 1/4". I'm afraid this is on the border line of too thick. Can I get away with this, or am I on the edge of too thick?

 

[Bob_VT]

Re: Thickness of transom for small clamp on outboards?

You will be fine. You are not too thick at all.

 

[zeke67]

Re: Thickness of transom for small clamp on outboards?

Thanks for the quick reply. I'm fine at two inches thick, or two and a quarter?

 

[Bob_VT]

Re: Thickness of transom for small clamp on outboards?

Either will work

 

[zeke67]

Re: Thickness of transom for small clamp on outboards?

thanks!

 

[oldboat1]

Re: Thickness of transom for small clamp on outboards?

think you are probably OK with those two motors, although I'm not sure about use of the 15 to 25hp on that hull (your option/judgment). In terms of transom width, though, I think you are likely to be too wide for smaller motors. On my Starcraft, the inside width was 1 1/2", like yours, but the outside plate was thinner stock (3/8", I think).

 

[zeke67]

Re: Thickness of transom for small clamp on outboards?

This hull was rated at either 25 or 30 according to a brochure I found. Not sure which and I can't find the brochure at the moment. This particular boat was originally paired with a '56 Johnson 30HP as far back as my family can remember. The 30 HP last ran in the early '90s and I still have it, but haven't gotten around to getting it going.

Your comment about 3/8 stock on the outside is helpful. The more I think about it the more I think that it's not 3/4" stock that's on there now. I think I'll make one of each and take both when I head north this summer.

 

[oldboat1]

Re: Thickness of transom for small clamp on outboards?

Hi Zeke. Sounds like a nice rig with a family history -- doesn't get much better than that. Thickness of that mounting plate is probably moot, as indicated above. Can eyeball it and then decide what looks best.