Despite being knocked on my back with illness late last week, I managed to get some stuff done toward the end of the weekend.
The logical follower to fuel fill lines is, fuel vent lines! All tank vent lines lead up to a small manifold mounted on the bulked near the deckfill. Each vent line has an inline “fuel stop” that prevents overfilling of the tank by keeping the vent line clear of fuel. Basically a check valve.
The combined “out” portion of the manifold leads back to the engine room, to which another hose which snakes up inside the coaming and down to a thru-hull vent fitting in the cockpit, just above one of the cockpit drains. This setup follows “all the rules” with the vents leading to the highest point (coaming) for the loop (reducing the chance of anything starting a siphon), down to an inconspicuous discharge outlet (kick panel of the cockpit), with no sags anywhere in the lines to trap air or fuel.
As each tank has its own vent hose that leads up near the deck fill, there is a greatly reduced chance of any cross-contamination of fuel between tanks. The only way it could happen is if any of the “fuel stop” valves fail and the boat is nearly upside down. In which case, we would have larger problems to worry about.
Also, to keep things tidy and organized, I machined a couple “hose mounting clamps” out of coosa.