All, My M-17 (#359) cockpit drains are routed from the fuel tank locker through hoses internal to the boat to exit underwater through aluminum through hull stub connections. The aluminum stubs are a bit corroded, but don’t appear to be unsafe, but I am considering modification to avoid the inevitable problem of leakage due to the corrosion. More recent builds have the cockpit drains located in the transom, about 3 inches above the waterline, about a foot port and starboard of centerline, through what appear to be Marelon thru hulls. On the MSOG site, Bob Eeg mentions using Whale check valves to prevent back flow into the fuel tank locker. Has anyone done this modification, and if so, are there “lessons learned” that I should be aware of? I’ve a bit of experience doing fiberglass hull repair (closing holes and openings that are no longer needed due to configuration changes with West System. Thanks. Will