2015-08-09 More on the boat:: the hull
My thoughts have oscillated between two shapes / materials: a styrofoam torpedo shaped boat, or a catamaran. The factors taken into account:
- The boat will capsize at one point or another, so it must be unsubmersible, and able to return statically to it's operating position. We must remember that the whole idea is that the boat has no power when there's no Sun, so we can't count on any active mechanism to do that.
- The boat must be robust and simple to build of course (I'm not a fiber glass building expert, and have no intention to become one, at least not for the first boat).
The catamaran has many advantages in term of stability and ease of use of the available space. However, it has a drawback: in my view a catamaran is likely to be stable both in operating condition and upside down. Stated another way, if it capsize, in won't get back in operating position by the sole virtue of its shape.
So I then toyed with the idea of a torpedo shaped, custom build styrofoam hull. The solar panel would be on the top, with the weight of an heavy enough thruster (under the hull, near the middle), maintaining the boat in the right position. Some ailerons may be needed to avoid oscillation around the roll axis.
Now a new factor comes into play: the solar panels are at least 70 cm wide, and they won't be near the diameter of the hull so the mechanical resistance isn't weakened too much. And there are several of them, which are 1m long, at least. All in all, to have a reasonable beam to length ratio, we would have a one piece at least 4 meters long, 90 cm width torpedo. Something quite difficult to handle.
A catamaran offers a much more interesting shape in this respect, so this gonna be my first shot.
After several considerations, I'm now working on an "open frame" design made of carbone tubes, which is more resistant than aluminium and only marginally more expensive.