Small sailboats could use these power units. As the output power of these units increases due to developing technology, sailboats could be one of the first applications of fuel cell propulsion. It takes relatively little power to move a typical pleasure sailboat through the water at a few knots. As this technology develops, it could be incorporated on progressively larger craft. A whole new class of boats, with specialized hull designs, could develop to incorporate the unique features of this technology.
Emergency power is separate from auxiliary power, as the requirements are significantly different.
These power sources must be stand alone. The power requirements are relatively small and the units generally must be portable. The units must be easily carried, preferably with the ability to float. The technology path is the same as described above but offers an independent starting point, which might be easier to develop because the power requirements are lower and the initially higher cost of improved reliability could be justified for emergency gear. In the long run, the manufacture of hydrogen must be sustainable, and that is being addressed through research organizations such as the Desert Research Institute.