Hi Donald: The 38,000btu instant unit from Bosch is perfect for marine, cabin or RV use. Also available are 125 & 165kbtu gas units for the home or commercial waterheating. Small & large electric units also work very well in marine applications. You may e-mail me at firstname.lastname@example.org or call me at 1-800 851 9891 for info. Tankless water heaters can be used anywhere, for heating water for ANY purpose. Regards from Brian, Tankless in Louisiana.