Maersk installed 100-foot-tall rotating sails on one of its tankers • Hacker News Board

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#231

Post by jhayward » Sun, Sep 02, 2018, 8:42 PM UTC

interdocken wrote: post #144

Jsharm wrote: post #133

A little embarrassed to ask but why would normal sails not work?

maintenance. the materials used for actual sails stretches eventually and is less effective. presumably these towers have very little to replace.

They have a very expensive, hard to replace, and high maintenance bearing at the base of the tower that carries the full force of the sail leveraged by a long moment arm. This bearing (along with lack of height = low wind) has been the reason that Flettner sails and wind turbines haven't been economical in the past.

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#232

Post by lsllc » Mon, Sep 03, 2018, 1:46 AM UTC

sandworm101 wrote: post #192

mabbo wrote: post #191

Earlier quoted context omitted.

Alternatively, the repair crew don't stay on the ship. Have a mobile team on a faster boat going ship to ship rescuing and repairing ones that can't make it to port again.

Maintenance is not repairs. The work needed to prevent repairs has to happen ever day. A crew at sea doesnt sit around waiting for an alarm. They are tending to equipment, verifying sensors ... even touching up paint is an essential daily task.

If you've ever been on a cruise, you'll notice the "crew" (not the staff) constantly painting and maintaining -- even on a brand new ship. If you ask, they'll tell you that they have to constantly work on the upkeep because of the size of the ship (kind of like painting the golden gate bridge, once you're done it's time to start over again).

Re: Maersk installed 100-foot-tall rotating sails on one of its tankers

#233

Post by cwmoore » Wed, Sep 05, 2018, 10:52 PM UTC

cwmoore wrote: post #190

LeifCarrotson wrote: post #183

Earlier quoted context omitted.

My assertion that it's a non-starter is based on the area of an 80 MW solar farm, not hydrodynamics. 80,000 kW x 24 hours / 1 kWh/m^2 = 2,000,000 square meters of solar cell area. That's a lot. In contrast, the ship has an area of 24,000 m^2. A light-weight solar system might weigh 10 kg/m^2, so the whole thing weighs 20,000 tons. The ship has a staggering capacity of 200,000 tons. So yes, it can carry it, but the 'l…

That is an interesting result. A 20 mi long piece of electronics floating in the open ocean would have [:deadpan:] more prohibitory issues than drag. Even if it were more optimistically estimated, this has obvious maneuverability (not to mention production) problems. They build ships the way they do for smart reasons, but I do like to explore the possibility space. The application that no one will ever pay for might…

Somebody made a way to start cleaning this up, and a proposal to pay to do it (front page 3 days later):

https://news.ycombinator.com/item?id=17899395