We are beginning to start building LT's and SD's soon and have built everything so far out of steel just because the availability to a welder and other fabricating goods. However we are looking into starting to use aluminum mostly to cut down on weight, and corrosion issues. But we were wondering if there were any companies out there with aluminum frames for both styles of motor? Would the strength be compromised? What other pro's and con's other than having to get new machines to fabricate, would there be with switching to aluminum? Thanks!

Beavertail has offered an aluminum frame, and I'm pretty sure Utah Marsh Motors are aluminum.

Aluminum is great on strength to weigh ratio. Just have to remember that with the abuse the motors go thru, the aluminum can fatigue and start cracking. I would imagine a lot of it would depend on how big you build it. Good luck.

I'm no fabricator but when I bought my first little rig the 23hp brigs was on an aluminum beaver tail frame and with in the first month the aluminum long tail frame broke 3 times. Each time I welded the a break it broke again in a different spot. This was all done in deep water during the summer so I knew it wouldn't make it through one hunt much less a season. I brought the motor to go devil manufacturers and put it on a galvanized frame. I don't know if the my first frame was just a lemon or if all the aluminum frames broke but I know I will never own an aluminum long tail.

So a longtail is not very practical... but a surface drive perhaps?

I would try it and test it out, but just from past experience I wouldn't do the long tail. Like I said I'm no fabricator or even a mechanic for that matter, I was just letting you know what happened with my aluminum long tail a couple years back.

Problem with aluminum is that it is prone to stress fractures, and once you weld it the area near the weld loses its heat treatment and is basically annealed back to its soft state leaving the area around the welds to be a lot weaker.

maybe all aluminum frame for the SD, but shaft housing for the SD be steel, bolted on.
QUAKKILLZ, where was you beavertail breaking at? youve also got to know whhat allows are best. youll probably want to worry about strength more than performance.

It broke right behind the engine where the little angle brackets go from the bottom rear of the engine to the shaft housing and then it broke on the flat bar that goes from the top rear of the engine to about halfway down the shaft housing.