You're right Jon, your posts about the heater were what got me to look into them last year. I installed the 2-outlet size, with one outlet facing forward, the other aft, from my galley island. My total heater run was about 24 ft (12 ft each way) and I wondered whether I would need a supplemental pump to move the fluid, but it seems to work fine without that complication. I don't have a Hot Water exchanger that the line needs to run through, so that simplifies my system a bit too. As you pointed out previously, the heater needs to be located below the level of the engine outlets.