The idea of utilizing waves to propel a boat remains a date around 1850. 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).
Figure 1: Drawings from Linden’s patent specification (Linden, 1895)
Wave propulsion methods other than using fins directly were also conceived more than 100 years ago. Otto Schulze of Brooklyn, New York, thought of using the wave-induced vertical motion of buoys along the hull of the boat to drive an ordinary propeller at the stern (Schulze, 1911)
(Figure 2: Drawing from Schulze’s patent specification (Schulze, 1911
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. In the latter half of the 20th century, more stories about people that had built wave-powered boats appeared. 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 (Anon., 1983). A maximum speed of six knots was recorded on one occasion. The Norwegian government-sponsored NOK 450,000 to fit the fishing research vessel Kystfangst (20 m long and 180 tonnes), owned by the Institute of Fishery Technology Research, with a bulbous bow and two foils with a total area of 3 m2 (Anon., 1983; Berg, 1985. In a sea state of about 3 m significant wave height, the foils produced a propulsive force corresponding to 16-22% of the vessel’s estimated resistance (Berg, 1985), or 16% when accounting for the strut resistance. 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.
Figure 3: Kystfangst (Dybdahl, 1988)
In the past few years, companies using this 150-year-old knowledge have been able to build an unmanned marine robot.
FATAH is one of these products. The robot was designed and built-in 2014 and was successfully tested in the Caspian Sea in 2015.
The FATAH also benefits from the waves and stored solar energies for propulsion and navigation. FATTAH is capable of carrying 30 kg payloads. The unmanned marine robot relies upon a 34-channel GNSS receiver as its primary navigation sensor and also carries a tilt-compensated magnetic compass with six-axis accelerometers and Gyroscopes. FATAH also carry a water speed sensor then all dates are processed with an EKF filter, allowing for short term dead reckoning. The FATTAH typical navigation accuracy is better than 5 meters.
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