Solar boats are the 20th century's main innovation in water transport and the beginning of a new era in the new millenium. Already they have grown from a novelty to an industry. Recent years have seen the rapid development of larger solar craft. These scale up favourably, as the main source of resistance through the water, wetted surface friction, increases slightly less rapidly than the increased area available for solar cells, and resistance due to wave-making becomes less and less important.

The following attempts to list the recent development of larger passenger solar and electric craft:

• The first passenger solar boats were built in 1995 by MW-Line in Yverdon, Switzerland. [12] Solifleur and Chlorophylle take 12 persons each and are operated by Pro Natura for nature excursions on the Lake of Neuchâtel. Contact: Pro Natura Champ-Pittet, CH-1400 Yverdon, telephone 024 4269341 <www.pronatura.ch>. [10] Suggested and implemented by the author, these were the first solar boats to be fitted with a mains connection in order to feed extra solar energy into the 230V grid when the boats are not being used. A few more similar boats of this type Aquabus 850 have since been built (8.5m length, 2.5m beam, 1.2 tonnes unloaded, 24 V Lynch motor).
  
  MW-Line built three boats for 25 passengers each on the Lake of Geneva. This service called Aquarel operates from June through September from Ouchy (Lausanne) to Lutry and St Sulpice (total round trip 20km) from Wednesday to Sunday 2-3 times per day. In 1999, the first year of operation, 6000 passengers were transported [20]. Info: Lausanne Tourism, telephone 021 613 73 73, private bookings: telephone 079 286 37 68. <www.lausanne.ch/aquarel> [13]
  
  
  
  Aquarel II on the Lake of Geneva (Picture supplied by Lausanne Tourist Info)
  
  A similar boat is in use in Milano. Operated by the Associazione Amici dei Navigli, Via Rasori 20, I-20145 Milano, who are dedicated to reopening the complete waterway from Lago Maggiore in Switzerland to the Adriatic Sea at Venice, the boat runs from Milano Darsena (1.5km SW from the geometrical city center) about 15km to Gaggiano (and back 15km) from Tuesday to Friday each evening and Saturday to Sunday each morning and afternoon (not winter). For bookings telephone 0347 7236610 (Fabia Malara).
  
  These four boats are of the type Aquabus 1050 (10.5m length, 2.5m beam, 2.3 tonnes unloaded, 48 V Lynch motor)
  All these boats and their panels produce more energy than they consume [11]. They are typically augmented by additional stationary panels for improving the balance in cloudy weather.
  
  MW-Line also electrified a 50-passenger boat on the Lac de Brenet (Jura) and a traditional 60-passenger boat with classic lines: the Bécassine is 20m long, 3.3m wide, and displaces 20 tonnes. It is in use since summer 2000 at Geneva (Quai du Mont-Blanc, near Grand Casino) and is mainly powered indirectly from stationary solar panels, but also has a few onboard panels. The range is given as 90 km at a speed of 10 knots. For bookings telephone 022 732 29 44.
  
  MW-Line was founded by Mark Wüst and partner Richard Mesple. They can be reached at 25 Route de Lausanne, CH-1400 Yverdon, telephone 024 426 33 87. <www.mwline.ch>
  
  
• The traditional boatyard SUEK GmbH near Vienna launched their solar catamaran Sonnenschein for up to 58 passengers in 1998, the first solar passenger craft of this size at the time [17]. It was used for excursions on the Danube. Unfortunately SUEK no longer exists. Sonnenschein was sold to the Saarbrückerner Personenschiff company in Germany (contact Mr. Hauck).
  Data: 15m length, 3.9m beam, 10 tonnes, 2 motors @ 6 kW, solar generator 5 kW.
  
  Sonnenschein (Picture supplied by SUEK)
  
  
  
  
• Kopf AG in Sulz am Neckar have built so many solar boats that one can speak of series production. Five types are available with relatively short production times. A RA31 for 12 passengers operated as a ferry on the Lake of Constance and transported 4000 passengers and 2000 bicycles between Gaienhofen in Germany and Steckborn in Switzerland during the years 1998 and 1999.
  Now this has been replaced by a RA 66 Solarshuttle for about 50 passengers and 20 bicycles [8], [6b], [21].
  
  RA 66 (two pictures by Bernd Kammerer supplied by Kopf Solardesign)
  
  
  
  
  
  Another RA66 Solarshuttle which was built in only 6 weeks is in service on the Maschsee in Hannover. It is operated by ÜSTRA, the Hannover local transport authority, who have many years experience with electric craft up to 100 passengers.
  
  The largest solar ship to date is the 27 m long RA82 Solarshuttle used touristicly under the name Alster Sonne on the Alster near Hamburg[23]. The 40-tonne ship for 100 passengers has seating for 84, costs 1.3 million DM, and also feeds the mains when it is not being used [4].
  
  RA82 Alster Sonne (Picture by Bernd Kammerer supplied by Kopf Design)
  
  
  
  Kopf has sold a number of the smaller RA models, including one to the Norfolk Broads Authority, possibly the first passenger solar boat in Great Britain. Contact: Kopf AG, D-72172 Sulz-Bergfelden.<www.kopf-solardesign.com>
  
  
• Robert Dane and team have developed the Solar Sailor in Australia. It is in use in Sydney Harbour since 2000. The Solar Sailor (also its prototype predecessor ) is the first larger solar craft to use solar and wind power together. Part of its solar cells are mounted on adjustable wingsails. The craft can travel by wind or sun alone or both together.Solar Sailor Pty Ltd, PO Box 336, Ulladulla, NSW 2539, Australia <www.solarsailor.com>
  
  
• In Newport Beach, California, the century-old river boat "Angela Luise" was converted to electric power. The 23 m boat is not solar, but can cruise for a day under batteries and host 100 passengers in a restaurant, bar and dance floor on two decks [16] Electric Boat News Spring 2000.
  
  
• Also not solar, but very powerful, is the electic Vaporetto in Venice. The operators ACTV started the project Vaporetto Elettrico E-1 in 1989. It is 23 m long, 4.6 m wide, 35 tonnes with a capacity for 208 passengers. During 3 years it was used for 12'000 hours, the 60kW motor using up to 400kWh per day. Although this is only a third of the energy used by the same craft fitted with diesel engines, the frequent rapid accelerations required meant several charging periods per day which didn't suit the rigorous timetable, so the boat was taken from regular service. [7]
  
  
• In 2000 the city of Strasbourg in France has added an electric boat to its fleet of sightseeing craft (guided trips for tourists). With 138 passengers, a length of 23.5 m, and a cost of 4.5 million FF this is the largest electric craft in France. It was conceived with help of the School of Engineering in Metz. The 12.5 tonnes of batteries give 12 hours running. I believe the boat was built by the Franco-Suisse Shipyard, Villers le Lac. The boat is reported to run well but there are cooling problems because it is fully enclosed and built like a greenhouse. (Info from Strasbourg Magazine Juin 2000)
  
  
• Rudolf Minder and Pierre Renaud are developing a solar catamaran for 150-250 passengers on the Jura Lakes in Switzerland. 33 m long, 100 tonnes, 10 tonnes batteries, 180 square meters solar panels, and a cruising speed of 15 km/h are the values indicated. The costs of about 2 million Sfr. are promised by several sponsors. <www.bielersee.ch/de/mobicat/index.htm>

  When these existing and projected examples of solar ships are compared to conventional diesel-powered ones, top speeds are usually lower, but average speeds on most inland waters are very similar because of speed restrictions on small lakes, rivers and canals. Surprisingly the costs of the solar craft seem to be similar or even lower. The big difference is of course that conventional craft cause considerable pollution and wavemaking, produce CO2 and use up oil, as do even electric craft indirectly powered by fossil-fueled power stations, whereas solar craft use few resources once they are built and can actually produce more power than they consume, if operated in a mains connection setup when not under way. Because sunlight is rather more predictable than wind in many areas, varies less, and can be stored by electrochemical means (batteries and hydrogen), solar ships may well eventually become the main means of transportation in some areas. Whether really large ships could be solarised remains to be seen. Cargo ships are generally built as cheaply as possible and presently lack the unobstructed deck area required for solar panels. Large passenger ships also tend to operate at speeds wasteful of power. Certainly there would be no problem operating ships with liquified hydrogen produced by vast solar plants in arid regions. Already several smaller boats exist which use hydrogen fuel cells.

  © Theodor Schmidt, 16.12.00/15.3.01