Saturday, April 4, 2009















Controller Tray

The control computer, cpu battery backup, Iridium modem, current sensor, and power switches are mounted on a tray that fits into the rear of the upper middle tube.
















Steering Controller Motor

The motor that rotates the shaft of the trolling motor is mounted in the same tube as the controller tray. The motor has an incremental shaft encoder rear mounted that translates the motor shaft rotation into quadrature pulses.


















Trolling Motor

This is the main proplusion motor. The motor is a Minn-Kota saltwater trolling motor that has the capability of 55 pounds of thurst at full speed - 24 Volts dc and 6 Amps. For longer endurance of the motor, it will never go above 50% of rated thrust.

Vessel in Dry Dock




Structural Concept






The vessel will have four ten feet long tubes held together by an aluminum structure. Each of the three aluminum surfaces shown in the picture on the left will be covered with 159 mm square solar cells, as represented by the black square. An aluminum wedge structure will be on the front to cut through the water, and the Minn-Kota trolling motor will be on the rear end of the vessel. The motor will be on a shaft that will rotate for steering 120 degrees.




Vessel in Dry Dock


Here is the aluminum structure on its back ready for the insertion of the 6 inch diameter schedule 80 pvc tubing.
Trip

The trip via each waypoint is 6217 mile long. The path was chosen to pick up the ocean current to the United States used by the early traders to this country. Currents for the trip during the summer months are favorable South from Spain/Portugal to the Western Coast of Africa, turning Northwest to near Puerto Rico and on to Tybee Island, Georgia.

Currents will be monitored in near real time from the NOAA satellites at http://www.oscar.noaa.gov/ . If an early summer hurricane or storm should be encounterd, a new set of trip waypoints will be downloaded over the Iridium link. Worse comes to worse, the boat will be stopped until conditions improve.

Simulated Trip

Before the actual trip is undertaken, a simulated trip with actual route coordinates will be done.

The distance between each waypoint was divided into 100,000 points and the latitude and longitude were calculated. These points were then inserted into NEMA 0183 GPRMC sentences that would normally be received from the GPS system. The simulated sentences will be fed to the vessel's control computer over a serial port that normally receives the output of the GPS receiver.

Several type of problems will be introduced at various points to simulate anticipated problems such as the control computer losing control, unexpected shutdown, or loss of total power.