Sunday, August 3, 2008

Combining photovoltaic and SWATH technologies in Marine Vehicles

by Charles Roring
One of the main obstacles in the application of solar energy technology in marine vehicles is the inadequate amount of power it supplies for running a ship or boat. When moving in the water, a ship or a boat must overcome frictional and wave resistance as well as wind resistance. The bigger the hull form the higher the energy it needs.
Most ships are using conventional hull form, i.e. a mono hull with holds for cargo and decks and superstructure for passengers accommodation.

Catamaran and SWATH
Both hull designs are meant to minimize wave resistance. On the average, for similar displacements, SWATH ships have lower wave resistance than catamaran.
To reduce the propelling power of a ship, engineers design new hull forms with lower wave resistance. Catamaran and SWATH (Small Waterplane Area Twin Hulls) are types of ship which have better performance. They are more stable and need less power. In addition they also have larger deck area which is suitable for the installation of solar photovoltaic modules.
With the same displacement and power consumption, catamaran and SWATH can move faster on the surface of the water. Therefore, they are also called high speed marine vehicle. SWATH ships are used to transport people in short distance. Faster speed means higher power. Improvements in photovoltaic technology have to be done in order to increase its efficiency so that it can easily be applied into many other applications both at sea and on land.

Small Waterplane Area Twin Hull
(SWATH ship)

Another innovative design for photovoltaic application in marine vehicle is solar sail boat of Sydney Australia. Here, engineers installed solar photovoltaic on panels that also function as sail.
Unfortunately, the cost of construction for these ships is still higher than the conventional mono hull ships.
Source of the pictures: SWATH and Catamaran hull design in Wikipedia
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