it is probably 10 years out now but i think natural gas will make it's way over to boats sooner then everyone thinks. compare natural gas to petroleum by energy output. The simplest and easiest method to compute the energy output is BTU. Natural gas is much much cheaper per BTU and the green house gas is substantially less. It also will drastically reduce our dependence on foreign countries which is a huge plus. The marine industry will be forced to adapt. There are many factors at play which slowly force things to change. Cost of NG vs petroleum, EPA standards, etc.

Gas stations will quickly adopt as well. There just has to be a way to convert current diesel engines to run on NG.