To start off, I don't have heat in my boat so I don't have any experience with it. But instead of running a heater tube up and all the way around the bow, why not just add a second heater to passenger side? I would think running water lines would be easier,more compact (than larger air hoses) and better heat output. Draw back is maybe cost, labor? and packaging the second heater core. How much will the air cool between the heater core and the outlet if the hose runs around the bow, kinda a long way for air. Just adding to your food for thought.