Let me correct myself, every bracket ever built is a flotation bracket.
So is every hull ever built.
If the vendor provides a dimensional scaled drawing, and weight of the product, I can do my own calculations.
I have everything I need now for the grady drive, need no specs from Grady.
The bracket can only be mounted so low on the transom, just like the grady drive is mounted, otherwise you run out of transom to thru bolt to. I don't see the big deal in positioning it - that is some kind of trade secret only marine service mechanics can master ?
So I'll take the drawing and lay it out in position as low as possible on an autocad drawing of my hull in profile, then figure difference in displacement with the computer. I have a waterline reference now from the bow right through the drive.
What's holding the boat the level it is now at rest is the massive hull creatin dispacement, not the tiny drive relatively speaking, with a 1/2 ton of motors off it in a cantiliver state on less. The further setback doesn't help it.
If I ever replace mine, I would like a lesser setback.
Since drive is tiny vs the hull, there's got to be a lot more volume on this product vs. grady drive to matter. Just to get a cubic foot more ain't easy. The photo's I've seen from below don't show a lot of difference to me, could be though, just didn't look that way. My grady drive is pretty massive as it begins at the hull, but looses depth and width as it extends to the rear.
When the vendor posts this non-proprietary info somewhere, I'll provide my on calcs of one vs. the other in displacement. It's not proprietary, since any one with a bracket can make a drawing from it, and weight it on a scale.
I'm a person of science, this is pure science, no hat trick and nothing to do with glass vs. metal construction. No smoke and mirror magic show.
And my car does drive better after wash and wax.