Fj igure 5.30 The pontoon boat Loon (Tamarack Lake Electric Boat Company).
a. motorboat, travelling entirely on sunlight, could achieve such a feat and she received a rapturous welcome on reaching New York.
The catamaran or pontoon form of hull is very popular for solar-powered boats, with sleek twin floats providing a good stable platform for PV, especially when raised on a canopy. However there is nothing to stop designers from using conventional monohulls; the main criterion is an efficient low-drag hull that creates minimal wash and uses the precious PV energy to best advantage.
Finally, we consider the question 'What exactly makes a boat solarpowered?” Exaggerated claims are sometimes made; it is easy to stick a PV module or two on a boat, and claim that it is powered by the sun. But it does PV no good to overstate its performance and capabilities, leading to disappointment and scepticism. One answer is to use a simple measure known as the solar boat index (SBI) to quantify performance and allow sensible comparison of a wide variety of boats carrying different amounts
of PV.