Buckethead905
Well-Known Member
You’ll want to replace all those Marelon thru-hull fittings while you’re at it with some nice stainless ones. I used Gemlux when I did mine and they are outstanding quality. Here is a YouTube link to their “duckbill” inserts, it’s high tech version of the ping-pong ball setup. With the duckbill setup you could theoretically have your your deck as little as an inch or two above the drains. 2 inches or 8 inches doesn’t make a difference, as long as the drain is lower, gravity will do its job, the duckbill will prevent any back flow. Gemlux also makes them with a rubber flap integrated into the opening of the thru-Hull which I have any works well preventing any back flow. The duckbill design is much slicker, regardless.