3 ms·

At perhaps 100 watts per square meter, a Maersk triple E ("An arbitrary large ship") at approximately 400 meters * 60 meters would generate 2.4 megawatts peak,

by mapt 8y ago

At perhaps 100 watts per square meter, a Maersk triple E ("An arbitrary large ship") at approximately 400 meters * 60 meters would generate 2.4 megawatts peak, or perhaps 400 kilowatts averaged. This is not nothing. It's roughly as much power as a redlined sports car engine. It might be sufficient to fight the worst ocean currents, since propulsion power scales so frighteningly faster than speed. https://www.maritime-executive.com/editorials/the-future-ultra-slow-unmanned-mega-ships https://www.maritime-executive.com/editorials/the-future-ult... It would also make sense, with larger ships, to just implement the nuclear tech we already have.

paulcole 8y ago
> This is not nothing. It's roughly as much power as a redlined sports car engine. And a sports car is what, 3,000 pounds? A container ship is something like 200,000 tons. I guess they can power a redlining sports car engine when out to sea but not a whole lot else.
- mapt 8y ago
  It doesn't take an enormous amount of power to move a big ship very very slowly; Froude's law, the first approximation of the relationship, scales power requirements with velocity squared. A Maersk Triple E has two up-to-30MW-each engines and a design speed of 19 knots. You'd scale down speed by a factor of 12 to achieve 1.6 knots (0.8m/s), and out of that you would get to scale down power by a factor of 144 to meet your ~400kw solar power endowment. The question is whether you can cross the most powerful currents, and at 1.6 knots you would certainly need to be cognizant of them to stand a chance, but you could ford them in the manner of fording a river: Get pushed downstream a bit, but cross the highest velocity area perpendicular. http://www.aoml.noaa.gov/phod/gdp/images/climatology.jpg http://www.aoml.noaa.gov/phod/gdp/images/climatology.jpg The Maersk Triple E and huge bulk carriers are practically worst-case-scenarios for solar, because there's so much ship to displace water under every square meter of solar. A smaller lighter catamaran is likely to find itself with dramatically higher speeds, albeit not linearly higher with hull depth, since a longer waterline is more efficient. I'm not suggesting this is practical. I think massive nuclear powered cargo ships capable of high speed is a hell of a lot more practical in a post-carbon world. But again: it's not nothing.
solatic 8y ago
> nuclear ships IANA(nuclear scientist) but I imagine that it has to do with the lack of nuclear engines available for the commercial market, which is due to nuclear technology being restricted by export controls and the like. Keeping nuclear engines and fuel out of the hands of others is much simpler when they're only on military ships with armories and soldiers, basically impossible on unarmed, undefended commerical shipping vessels. Do correct me if I'm wrong ...

by mapt 8y ago

paulcole 8y ago

> This is not nothing. It's roughly as much power as a redlined sports car engine. And a sports car is what, 3,000 pounds? A container ship is something like 200,000 tons. I guess they can power a redlining sports car engine when out to sea but not a whole lot else.

mapt 8y ago
It doesn't take an enormous amount of power to move a big ship very very slowly; Froude's law, the first approximation of the relationship, scales power requirements with velocity squared. A Maersk Triple E has two up-to-30MW-each engines and a design speed of 19 knots. You'd scale down speed by a factor of 12 to achieve 1.6 knots (0.8m/s), and out of that you would get to scale down power by a factor of 144 to meet your ~400kw solar power endowment. The question is whether you can cross the most powerful currents, and at 1.6 knots you would certainly need to be cognizant of them to stand a chance, but you could ford them in the manner of fording a river: Get pushed downstream a bit, but cross the highest velocity area perpendicular. http://www.aoml.noaa.gov/phod/gdp/images/climatology.jpg http://www.aoml.noaa.gov/phod/gdp/images/climatology.jpg The Maersk Triple E and huge bulk carriers are practically worst-case-scenarios for solar, because there's so much ship to displace water under every square meter of solar. A smaller lighter catamaran is likely to find itself with dramatically higher speeds, albeit not linearly higher with hull depth, since a longer waterline is more efficient. I'm not suggesting this is practical. I think massive nuclear powered cargo ships capable of high speed is a hell of a lot more practical in a post-carbon world. But again: it's not nothing.

solatic 8y ago

> nuclear ships IANA(nuclear scientist) but I imagine that it has to do with the lack of nuclear engines available for the commercial market, which is due to nuclear technology being restricted by export controls and the like. Keeping nuclear engines and fuel out of the hands of others is much simpler when they're only on military ships with armories and soldiers, basically impossible on unarmed, undefended commerical shipping vessels. Do correct me if I'm wrong ...