Quote:
Originally Posted by FishStretcher
I did some stress analysis on a 24" bracket with (importantly) a center rib in the flotation volume.
The center rib helps a lot. . . .
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Nice analysis! FYI, Don's bracket has a center rib much like you've shown but it appears to be the full height of the tub. Most structural problems begin at stress concentrations, and there are some concentrated stresses on Don's bracket (as indicated by gel coat cracks) right at the 90 degree concave corners of the swim platform where it extends back to the motor mounting surface. Gel coat is so brittle that it's just cosmetic and I'm not concerned about it, but he's looking at adding a 45 degree gusset there to spread out the loads in that area and eliminate those cracks. Most aluminum is much more ductile than gel coat, so you shouldn't have a problem, but if you're concerned about stresses, that's one area I'd pay close attention to and make sure you have large radii and no sharp edges or other stress risers in that general area. Denny