wave powered boats

[구름치기]

The history of wave-powered boats

Utilizing waves to propel a boat forward is far from a new idea. It is known that whalers throughout history cut off the flukes of the whales they had killed, as it was observed that a dead whale propelled itself forward at a speed of about 1 knot due to the action of the sea (Bose and Lien, 1990). It is not unthinkable that this could have sparked the idea of using the same principle to propel a boat against the waves, among some of the whalers who witnessed this phenomenon.

1850 - 1899

The earliest known document describing a wave-powered boat is a US patent by Daniel Vrooman of Hudson, Ohio (Vrooman, 1858), from 1858. In his patent, see Fig. 1, he describes "[...] a new and useful improvement in ships and other vessels for enabling their up and down motion from the rolling of the sea and other causes and the corresponding movement of the water to aid in propelling them on their course [...]". Vrooman explains how this can be achieved by attaching elastic fins or wings to the bow, bilge run, and counter of the ship. It appears, however, that Vrooman did not build his wave-powered boat, as his patent reads: "To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation." It is not known whether or not someone else actually built Vrooman뭩 boat.

Fig. 1: Drawings from Vrooman's patent specification. Side view of the hull to the left, stern view of the hull to the right.

Hermann Linden of the Zoological Station in Naples, Italy, filed a British patent for a wave-powered boat in 1895 (Linden, 1895), see Fig. 3. Based on his patent, Linden built a 13 ft long boat named Autonaut (Burnett, 1979), which moved against the waves at three to four miles per hour, powered purely by the energy of the waves. The boat obtained its thrust from two underwater steel plates, one at the bow and one at the stern. The plates were fixed at one end and feathered like fish fins as the boat moved up and down due to the waves. Linden proceeded to build a 24 ft long boat being able to tow two 10 ft boats, each containing two passengers, at nearly four miles per hour.

Fig. 2: A drawing of the Autonaut from Pearson's Magazine, December 1898 (Burnett, 1979).

Fig. 3: Drawings from Linden's patent specification.

1900 - 1949

Other methods of utilizing wave energy for propulsion than through fins directly were also thought of more than 100 years ago. Otto Schulz of Brooklyn, New York, had an idea of utilizing the wave induced up and down motion of buoys along the hull of the boat to drive an ordinary propeller at the stern, see Fig. 4 (Schulze, 1911). Schulze also considered using the wave energy to generate electricity for later use, either for driving the propeller, or for other purposes. Again, it is not known whether or not the boat was built.

Fig. 4: Drawing from Schulze's patent specification.

Although receiving praise in the contemporary newspapers from New York (The New York Times, 1898) to New Zealand (Ashburton Guardian, 1897), Linden뭩 boat must have been forgotten by the scientific community, because in 1935, Popular Science claims that it remained for an inventor of Long Beach, California, whose name is not mentioned, to design a wave-operated mechanism to propel a boat (Popular Science, 1935), see Fig. 5. Two fins in the bow and one fin in the stern attached to flexible joints provided the propulsion. The 18-inch model built by the inventor could reportedly attain a pace of five miles per hour, with its relatively large fins compared to the waterplane area of the hull, as seen in Fig.6.

Fig. 5: The unnamed inventor of Long Beach with his wave-powered model boat in 1935 (Popular Science, 1935).

Fig. 6: Close-up view of the wave-powered model boat of 1935 (Popular Science, 1935).

Fig. 7: John S. McCubbin's boat of 1950 (Popular Science, 1950).

1950 - 1975

In the latter half of the 20th century, more stories on people that had built a wave-powered boat appeared. These people include John S. McCubbin of Victoria, Australia (Popular Science, 1950), and Joseph A. Gause (Mechanix Illustrated, 1972) of Burlington, Ontario, Canada. Gause filed his first patent for a wave-powered boat in 1966 (Gause, 1966). Gause뭩 34 ft boat, Gausefin I, attained a top speed of 5 mph on Lake Ontario, using wave energy only, witnessed by five Canadian Government officials who were cruising alongside. Gausefin I had three pairs of fixed fins rigidly attached to the hull. The fins were thickest at the root and gradually tapered outward toward a thin trailing edge allowing for the fins to flex when hit by a wave. According to the Mechanix Ilustrated article, ?...] the size, angle, thickness and flexibility of the fins were arrived at througth guesstimating.� Gause, a sculptor and painter, certainly knew the historical background of wave-powered boats, as he cites both Vrooman and the Popular Science article of 1950 in one of his four patents (Gause, 1967).

Fig. 8: The Gausefin I: Bow to the left, and stern to the right (Mechanix Illustrated, 1972).

1975 - 2000

Einar Jakobsen started his experiments on wave-powered boats in Norway in 1978. In 1981, he presented results (Jakobsen, 1981) from experiments performed at the Norwegian Hydrodynamics Laboratories (today MARINTEK) in Trondheim, Norway. Jakobsen뭩 model boat of length 1.02 m, moved at a speed of 1.15 m/s in regular head sea waves of waveheight 0.13 m and wave period 1.2 s. Froude-scaled to full scale, this is equivalent of a 40 m long ship propelling itself forward solely by wave power in head sea waves of height 5.2 m at a speed of 14 kn. The speed in following waves was about 15% lower. The model had a spring-regulated foil on an extension out from the bow, and another spring-regulated foil on an extension aft of the stern. Einar Jakobsen termed the device a "foilpropeller".

Fig. 9: The bow of the 7.5 m hull used in tests on Wave Control Company's "foilpropeller" (Anon., 1983).

Jakobsen and his Wave Control Company used combinations of two and four foils, each measuring 0.5 m² on a 7.5 m long sailboat hull, see Fig. 9 (Anon., 1983). A maximum speed of six knots was recorded on one occation. Jakobsen then managed to get NOK 450 000 from the Norwegian government for equipping the 20.4 m fishing research vessel Kystfangst, owned by the Institute of Fishery Technology Research, with a bulbous bow and two foils on each side of the bow (Anon., 1983), see Fig. 10. In a seastate of about 3 m wave height, the foils produced a propulsive force corresponding to 15-20 % of the vessel뭩 total resistance (Berg, 1985). The vessel speed was 4-8 knots. Reduced pitching motion of the vessel in head seas and reduced rolling motion in following seas were observed.

The wave periods of 7-7.5 seconds that Kystfangst was tested in give wavelengths of about 80 m, or 4 times the length of Kystfangst. Model tests (Kj�rland, 1979; Nagata et al., 2010) have shown that the largest speeds of wave-powered ships occur when the wave length is about 1.1-1.2 times the ship length in beam and following seas, and 2-3 times the ship length in head seas. In other words, Kystfangst would have benefited more from the foils had she been longer.

Fig. 10: Kystfangst in 1986 (Dybdahl, 1988).

Simultaneously with Jakobsen뭩 work, Hiroshi Isshiki of the Techincal Research Institute, Hitachi Shipbuilding & Engineering Co., Ltd. in Osaka, Japan began a thorough theoretical and experimental study of wave-powered boats (Isshiki, 1982a,b; Isshiki and Murakami, 1983, 1984). Isshiki used the term "wave devouring propulsion", allegedly proposed by Prof. T. Y. Wu of the California Institute of Technology in 1980. Yukata Terao of Tokai University in Japan was also working on "wave devouring propulsion" at the time (Terao, 1982). In 1991, Isshiki and Terao presented results from full scale tests on 15.7 m long fishing vessel (Terao and Isshiki, 1991), see Fig. 11. The projected hydrofoil area was 7.4 % of the ship뭩 waterline area. Using the bow foil resulted in reduced pitching motion, reduced bow slamming, and a speed increase in waves.

Fig. 11: The 20-ton fishing vessel equipped with a bow foil tested in 1988/89 (Terao and Isshiki, 1991).

2000 - present

In 2008, Japanese sailor and environmentalist Kenichi Horie sailed the wave-powered catamaran Suntory Mermaid II, see Figs. 12 and 13, from Honolulu, Hawaii, to the Kii Channel, Japan (Geoghegan, 2008). The boat뭩 propulsion system was designed by Yukata Terao. The journey took 110 days, which was longer than planned, due to unusually good weather and calm seas. The journey is to date the longest known voyage by a wave-powered boat. The Suntory Mermaid II was widely, yet wrongly, described on the Internet as "The world뭩 first wave-powered boat".

Fig. 12: Kenichi Horie onboard the Suntory Mermaid II, which sailed from Hawaii to Japan in 2008 (Fabre, 2008).

Fig. 13: The propulsion mechanism of the Suntory Mermaid II (Popular Science, 2008).

Nagata et al. (2010) performed model tests of a 2 m long model of an 80 m long container ship. The ship was equipped with a wave-foil propulsor in the bow, of span 2.34 times the ship beam. In head sea waves of wavelength 3.12 times the ship length (Lpp) and height 0.10 m, the ship cruised at about 0.7 m/s, powered only by the waves. Almost the same speed was achieved in following sea with the same wave height, but with a wave length of 0.96 times Lpp. Froude-scaled to full scale, this is equivalent of an 80 m ship sailing at 8.6 knots in waves of 4 m height.

References

Anon. (1983). Wave power for ship propulsion. The Motor Ship, 64(757):67�69.

Ashburton Guardian (1897). A boat with fins. Volume XVIII, Issue 4281, 30 August 1897.

Berg, A. (1985). Trials with passive foil propulsion on M/S Kystfangst. Project no. 672.138. Technical report, Fiskeriteknologisk Forskningsinstitutt, Fart�yseksjon, Marinteknisk senter, H�kon H�konsensgt. 34, 7000, Trondheim.

Bose, N. and Lien, J. (1990). Energy Absorption from Ocean Waves: A Free Ride for Cetaceans. In Proc. R. Soc. Lond., volume B 240, pages 591�605.

Burnett, R. F. (1979). Wave energy for propelling craft - nothing new. The Naval Architect. Nov. 1979, p. 239.

Dybdahl, K. (1988). Foilpropellen kan revolusjonere skipsfarten. Teknisk Ukeblad/ Teknikk, no. 39, October 1988, pp. 10-11.

Fabre, O. (2008). Japan sailor takes on pacific in wave-powered boat. Reuters, March 17, 2008. Retrieved June 29, 2011.

Gause, J. A. (1966). Flexible fin propulsion member and vessels incorporated same. GB Patent 1176559. Filed Sept. 7, 1966. Patented Jan. 7, 1970.

Gause, J. A. (1967). Water-borne vessel comprising propulsion system incorporating flexible fin propulsion members. US Patent 3,453,981. Filed Apr. 24, 1967. Patented Jul. 8, 1969.

Geoghegan, J. J. (2008). Boat, moved only by waves, sails to a seafaring first. The New York Times. July 8, 2008. Retrieved June 29, 2011.

Isshiki, H. (1982a). A theory of wave devouring propulsion (1st Report) - Thrust generation by a linear Wells turbine. J. Soc. Naval Arch. Japan, (151):54�64.

Isshiki, H. (1982b). A theory of wave devouring propulsion (2nd Report) - Optimized foil motions for a passive-type wave devouring propulsor. J. Soc. Naval Arch. Japan, (152):89�100.

Isshiki, H. and Murakami, M. (1983). A theory of wave devouring propulsion (3rd Report) - An experimental verification of thrust generation by a passive-type hydrofoil propulsor. J. Soc. Naval Arch. Japan, (154):118�128.

Isshiki, H. and Murakami, M. (1984). A theory of wave devouring propulsion (4th Report) - A comparison between theory and experiment in case of a passive-type hydrofoil propulsor. J. Soc. Naval Arch. Japan, (156):102�114.

Jakobsen, E. (1981). The foilpropeller, wave power for propulsion. In Papers presented at the Second International Symposium on Wave & Tidal Energy, pages 363�369.

Kj�rland, O. (1979). Model tests with a wave propulsion system. Com.R.SMT 43.8 4344006. Technical report, The Ship Research Institute of Norway.

Linden, H. (1895). Improved combination with floating bodies, of fins adapted to effect their propulsion. GB Patent 14,630. Filed Aug. 1, 1895. Patented Jul. 18, 1896.

Mechanix Illustrated (1972). Mr. Gause뭩 incredible self-propelled boat! Oct. 1972, pp. 22 and 179.

Nagata, S., Imai, Y., Toyota, K., and Isshiki, H. (2010). Thrust generation by waves. In Proc. of the Ninth ISOPE Pacific/Asia Offshore Mechanics Symposium, Busan, Korea, November 14-17, 2010, pages 155�162.

Popular Science (1935). Wave power runs model boat. April 1935, p. 26.

Popular Science (1950). Waves serve as boat뭩 engine. February 1950, p. 224.

Popular Science (2008). Wave runner. March 2008. Retrieved December 3, 2011.

Schulze, O. (1911). Wave motor. US Patent 1,033,476. Filed Jan. 5, 1911. Patented Jul. 23, 1912.

Terao, Y. (1982). A floating structure which moves towards the waves (possibility of wave devouring propulsion. Journal of the Kansai Society of Naval Architects, Japan, (184):51�54. In Japanese.

Terao, Y. and Isshiki, H. (1991). Wave devouring propulsion sea trial. In Eighteenth Symposium on Naval Hydrodynamics, pages 287�296.

The New York Times (1898). A self-propelling boat. December 18, 1898.

Vrooman, D. (1858). Vibrating propeller. US Patent 22,097. Patented Nov. 15, 1858.