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Solar-Powered Boat Carries 8.5 Tons of Lithium-Ion Batteries
bshell writes "The Verge has a great photo-essay about Tûranor PlanetSolar, the first boat to circle the globe with solar power. 'The 89,000 kg (nearly 100 ton) ship needs a massive solar array to capture enough energy to push itself through the ocean. An impressive 512 square meters (roughly 5,500 square feet) of photovoltaic cells, to be exact, charge the 8.5 tons of lithium-ion batteries that are stored in the ship's two hulls.' The boat is currently in NYC. Among other remarkable facts, the captain (Gérard d'Aboville) is one of those rare individuals who solo-rowed across both the Atlantic and Pacific Oceans, journeys that took 71 and 134 days, respectively. The piece has a lot of detail about control systems and design."
I'm sorry but this is complete nonsense.Francis Chichester sailed around the world under solar power in 1966.
I suspect it was a lot "greener" to build his boat that this.
No wonder Jeremy Clarkson talks about the "green monster"
Anyone have an estimate of how much energy it takes to produce and transport 17,000 pounds of lithium ion batteries?
Is this really an efficient solar use compared to, say, sail?
Moving heavy loads by sea is very efficient. You don't see "container-planes" for a reason. The buoyancy from the displaced water does the lifting, you just move it.
square hulls don't require ballast, they're stable by nature of the shape. Neither do catamarans or trimarans, they're stable for much the same reason that square hulls are: edge displacement equals or is greater than centre displacement.
An ASCII demonstration:
\/ : single-keel trangular hull. Not very stable because at each point on the hull a different upward pressure acts, resulting in something that requires ballast in the bottom to keep it pointed the right way and/or....
Y : triangular hull with sail. Only stable because of the sail (which has ballast in it). Without it, it's about as stable as a log in white water.
\_/ : still a triangular hull, this time with a double keel. More stable than the single keel (above), but think of the small rowboats one would use on a lake. Obviously the wider the hull in relation to the length, the more stable it's going to be, but it ain't gonna be capsize-proof. Would still require ballast if it's doing anything other than glass-still laking.
|_| : square hull. Very stable because the same upward pressure acts on every point of the hull bottom. Wider=capsize proofing. If you could make a double wardrobe watertight, it would be brilliant as a rescue/evac boat in case of disastrous flooding, because it would hold as much human weight as the total volume of water displaced (40 cubic feet to an inch of the side, for argument's sake, that's 1.13 cubic metres - that's over a ton of water, or a dozen to fifteen full grown adults) and still be rock solid stable.
Operation Guillotine is in effect.
you're only correct if youre talking about a hull riding smack on the surface and not extending beneath it. ie, you're ignoring CG, displacement, and actual bouyancy dynamics and vastly oversimplifying the problem.
the bouyancy forces acting on a hull dont care if they are acting on the angled side of a V hull or the flat bottom of...well a flat bottomed boat.
the surface area of the horizontal plane of the boat hull where it intersects the waterline is effectively a "flat hull", or the "area upon which the bouyancy forces act", for any boat, regardless of whether the hull is a perfect square or a perfect circle or inverted triangle.
two hulls with different shapes but the same surface area of that plane (and the same displacement and CG are equivealent) will have the same bouyancy forces acting upwards on the hull.
The guy who said the election was rigged won the presidency with the second-most votes.