I'm in the process of installing a 2kW heater in the bow of a Silver Streak 18'6" Challenger. Do you guys that have them, run the combustion air intake to a fresh source? I've installed a thru hull for the exhaust but didn't consider combustion air. The manual says not to pull cabin air for combustion, but I'm thinking the ventilation in this boat would be more than adequate to do so. It's only a drop curtain so there are rather air intake holes in the gunnels where the curtain doesn't cover. Silver Streak installs Wallas as a factory option and I don't believe they have a separate combustion air intake duct installed. I will be installing a CO detector right away as well.