Slashdot Mirror
Solar Boat To Cross the Atlantic
Roland Piquepaille writes, "A group from Switzerland will soon attempt the first Atlantic crossing in a solar-powered boat. This ship, named SUN21, is a 14-meter-long catamaran able to sleep 5 or 6 persons. The goal is to leave Seville, Spain, in December 2006 and to reach ports in Florida and New York in the spring of 2007. This boat will achieve its 7,000-mile trip at a speed of 5-6 knots, about the speed of a sailing yacht, by using photovoltaic cells and without burning a single gallon of fuel. The consortium behind this project wants to demonstrate that the time has come for solar boats." The boat will cost about $556,000 to build and it will be for sale at some point after its crossing.
Every sailing vessel is basically a solar powered boat. Been doing that for eons. Why change now?
Catboats with sails makes a very reliable clip night and day with little or no fancy technology - and can easily be mated up to such a solar-panel system for an added kick and redundancy...
Finally, an alternative to the environmentally dangerous effects of the sail.
But how much oil did it take to make the solar cells?
Censorship is obscene. Patriotism is bigotry. Faith is a vice. Slashdot 2.0 sucks.
Okay, so we currently have the ability to have the front page not show articles posted by specific Slashdot editors. How about expanding that, so we can specify specific submitters, such as Roland Piquepaille for example, who's articles don't show up?
Duct tape is like the Force. It has a light side, a dark side, and it holds the universe together.
the ship will undertake the first motorized crossing of the Atlantic without using a drop of gasoline
Except for all the nuclear powered ships and submarines.
From the web-page: "Much of the expanding long-distance goods traffic on our oceans as well as many leisure boats could be powered by ecological solar energy. Solar energy will be the future of navigation techniques. But it needs more publicity and more confidence."
It sounds nice, but the practical application for the actual transportation of goods is something else.
The great things about ships is that the volume increases as a cubic function (roughly) of the length, but the drag only increases as the square. The area available to solar energy is more like a direct linear relationship to length what with ships being kind of long and skinny. That means that you can eventually build a ship big enough to carry it's own fuel to cross an ocean, and if you go bigger it can carry cargo even. Bigger still means more cargo with less fuel per cargo needed (generally). This is why we now have 1000 foot long container ships and 300,000 DWT ULCCs (Ultra Large Crude Carriers). But these ships that require less energy per volume still require a *lot* of energy, and not just energy, put power too (they need that energy fast). For example, the ship I work on (600 feet long by 75 feet wide, about 20,000 GRT--small by today's standards) requires about 14,000 horsepower to travel at about 17 knots when fully loaded. Just using a crude area approximation for the ship's dimensions and, say, 33% efficiency for solar cells you would get about 1630 kW of power, or about 2180 horsepower. 2180 horsepower won't even move a ship that size fast enough to maintain steerage. This isn't even mentioning the other auxiliary electrical loads associated with a ship (pumps, motors, air conditioning, sewage processing, etc.). Factoring average load for my ship in to that, you get about 1000 kW (1350 HP) available for propulsion. This is like trying to row a canoe with a spoon. Of course, if you don't put anything in the ship power consumption goes way down and you eventually get to the point where you have a boat like what they're using. But what business that makes money by moving lots of goods from A to B on a schedule is going to build a fleet of boats that can't carry anything and go very slowly? Maybe recreational boaters, but I don't see it so much for the commercial shipping industry.
I do wish them fair winds and following seas for their crossing, and hope that they are indeed correct that "Solar energy will be the future of navigation techniques" if for no other reason than we need to, as a society, start reducing out carbon footprint. As an engineer (a marine engineer, at that), though, I see a very long a tortuous path ahead.
If your toast does not accquire any kind of royalty, please do not contact us. We can't help you.
1. Effectively, sailboats can go "straight into the wind" by zigzagging (tacking). Unfortunately, this doesn't work so well in narrow channels (e.g. rivers). In this regard, the solar ship would have an edge, particularly on heavily used rivers.
2. As many people here have pointed out, sailboats have been around for a very long time, meaning that we've had a lot of time to improve their design and construction. If the first generation of a solar ship can be competitive with current generation sailboats, I think that this bodes well for the solar ship in the long haul.
3. Owing to the enormous forces involved in propelling a large ship using wind, the design, construction and operation of sailing vessels can be quite expensive. Half a million for a boat that can cross the Atlantic doesn't seem so bad, especially for a first-generation custom-built effort. With large scale production, I would expect to see prices come down.
4. The masts, sails and standing rigging of a sailing vessel seem incompatible with modern top-loading cargo facilities, whereas I can imagine that a solar boat could be designed for compatibility with existing port equipment.
5. Although batteries weigh a lot, so does fuel. And, unlike cars and trucks driving cross-country, ships crossing an ocean don't have the luxury of refueling, so they have to carry it all with them. On a solar-powered ship, you just need enough battery capacity to get you through cloudy patches.
I'm not 100% convinced it'll work, but the idea has merit.