I bought a 35hp dmm, and for now I need to put it on a 15x48 alweld until I can have uncle j or Bbb build me one.
My question is, I know the transom isn't going to be strong enough for a 240# motor so what can I do to beef this transome up so it can handle this thing for the next 7 months? It currently has small corner peices and no supports going from rib to transome, and the transome it's self id be lieing to you if I told you how thick it is.,

That 35 is probably a little much for a 15', but may work. I have a 1648 weld bilt and all I did was cut the transom from 20" to 16" to accommodate my 23 gdlt. I bought a 31 mb sd back in February and just threw it on there and works fine, how ever the first chance I get I plan on welding a piece of plate on the back side and 2 flat bars on the inside running from the channel on the top going down. The channel was put on top the transom when it was cut down and I figure if I weld the flat bars from the channel down and have them spaced wide enough to drill the holes for the mounting bolts to run through and have the plate on the backside welded to the channel it would make it a lot more rigid and hold up a lot longer. It's held up fine so far and I use it very often but I want to do this before duck season for sure. Maybe some others might chime in with some better ideas. I can just about promise you'll have porpoising problem but that can be an easy fix. If you gonna be welding on the transom just weld a single bead pass on each side on the bottom of the boat as far back as u can from the outside going in about 8" long, thats what I did and it worked.

Porpoising?

im fixing to have the same problem with my 1652 with a mb 4500 what i plan on doing before the motor comes in is welding a .25 or bigger al plate on the back side and maybe the inside and put two more gussets on the inside on eather side of the original one that was there and any other ideas i can come up with to help

im fixing to have the same problem with my 1652 with a mb 4500 what i plan on doing before the motor comes in is welding a .25 or bigger al plate on the back side and maybe the inside and put two more gussets on the inside on eather side of the original one that was there and any other ideas i can come up with to help

Ah ok lol we call that needing to be trimmed down, I'm used to outboards. Gotcha though thank you but , if I don't give it full throttle it shouldn't do it correct? I mean a 40hp was on it before this.

You cannot compare an outboard to a surface drive. If you trim down a surface drive, it will not be running at the surface. Mine porpoised at fairly slow speeds too until I moved weight up front.

Yea, I understand, was just relating it to what I know. So if it's porpoising I need to get done one to sit up front or move my gas and battery up front. But anyways any suggestions on the transom?