[Ed]

Jim-

If you're concerned about water flowing in, instead of flowing out....you can always install a bronze check valve to the thru-hull on the inside of the transom. It only lets water flow out....not in.

This spring, I replaced all thru-hulls on my Mako....and in doing so....I installed bronze seacocks (ball checks) on the baitwell intake and drain lines (helpful if you ever split a line...just turn them off. I also installed a bronze checkvalve on the overflow line for the bait well. Originally, Mako just had the line mated to a plastic thru hull with an Attwood/Perko type scupper over it. But when I replaced plastic thru hull with a bronze one, I couldnt find a scupper big enough so installed a checkvalve instead. Works like a charm. This is how Mako is currently rigging there 31 center console.

-Ed-