Wednesday, February 7, 2007

Our Energy Future: Hydrogen Fishing Boats

As a charter captain and avid fisherman alternate fuels and power plants for the boating industry is a major consideration. Since Fuel Cell Vehicles (FCV) will probably rule the roads, what about the waterways?

Boats have different power needs that cars. A boat runs at or near maximum horsepower anytime they are running, cars can coast a bit using gearing. Also boats live and work in a far more inhospitable environment than cars. Electricity and salty, high humidity environments don’t play well together.

This makes using electric power propulsion systems in boat a little more complicated but not impractical. So to continue my optimistic green power theme I would like to present my concept boat of the future.

The boat is based on a 26 foot Panga style hull design, as this style hull is very energy efficient. Pangas can be inboard or outboard powered. To simplify design let’s use an outboard configuration.

The power plant for the concept boat is in two parts, the fuel cell and the electric power motor. To equalize weight load distribution, the fuel cell will be mounted forward to offset the aft engine weight.

For the outboard motor a 90-horsepower Mercury midsection and lower unit is used (Mercury just to keep it made in America as much as possible). The internal combustion engine is replaced with a 125KW electric motor weighing just over 100-pounds. So the net weight of the aft portion of the power plant is roughly the same as normal outboard motor. To have the roughly the same performance as a typical gasoline powered Panga twin engines will be installed.

This electric motor was selected for its lightweight, compact size and high efficiency. The motor is water-cooled allowing for complete sealing of the motor for protection against the marine environment. Adaptation to the outboard midsection should be simple and the power head portion would have a much lower profile. (See

The fuel cell adds about 460 pounds to the concept boat. A considerable amount of added weight, but much less than you were probably expecting. The fuel cell selected has maximum continuous output of 210KW (based on estimates using modified stacked Honda V flow fuel cells, weight estimates may be a little low see

Fuel storage will have to be liquid hydrogen to provide acceptable range in a reasonable space. With the increase efficiency of the fuel cell/electric power plant and the higher energy content of hydrogen, the fuel storage space requirement is rough the same as for gasoline.

Allowing for fuel tank insulation and the added weight of the fuel cell, the boat deck height should be raised approximately 2 inches. If not the boat would tend to be wet footed. If you are designing a concept boat may as well make it comfortable.

Now for the good part, performance! With a continuous 210KW output equal to approximately 160 horsepower at the prop, the FCV Panga should cruise at a respectable 24 knots. Fuel efficiency would be on the order of 6 miles per gallon in gasoline equivalent terms. Not bad at all!

With newer fuel cell designs that are increasing efficiency and reducing weight, even better performance can be expected in the not so distant future. Safety considerations using hydrogen are of course a major concern. So I won’t be building this concept boat this weekend. Still the fuel cell powered small fishing boat doesn’t seem as for off in the future as it did just a few years ago.

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