At first glance, that looks good to me. I did some FEA on one a while back, and the deep rib in the bottom helps lots.
It is here:
http://www.classicseacraft.com/commu...t=23274&page=4
I could never figure a good way to get the swim platform well connected to the tub, though.
Others who have glass brackets had some good observations in there, too. I suspect that tabbing at the crown of the rib is a PITA with epoxy. Mat glass has a bad rap, but it wets out in poly and vinylester(epoxy) and goes around compound curves. It doesn't wet out the same in epoxy (it stays stuck together when there is not styrene in the resin). I have a hard time with 1708 on compound curves. Others might have tips for this. I would just use mat in VE/PE, and a fair amount of it for tabbing the top of the rib to the ends of the bracket. But I haven't actually built one. Others have. They might have good advice (and maybe I can learn something from them with 1708 for compound curves).