neat steamboat concepts more for RC but not environmentally friendly (makes noise and heat to the ecosystem) fish have sensitive ears. what youd want for larger boat is something that shoots steam into the air kinda like a paddle boat. could probably even convert an old small block engine to run on steam generated from a parabolic dish or trough system.
i’ve seen the regular steam boats built with different length intake exhaust also pinched at the intake kinda like a check valve.
uniflo turbine only one moving part