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Having spent a little time on the sea, it's remarkable how much weather impedes any operations, and naturally accidents often happen at night in bad weather. T

Having spent a little time on the sea, it's remarkable how much weather impedes any operations, and naturally accidents often happen at night in bad weather. These huge ferries just had to wait there and about a hundred people died right outside in the sea. Just running a regular rubber boat in normally windy weather on the Baltic is next to useless as the propeller spends a large portion of time out of the water and you can't get anywhere. Coast guards and specialized rescuers have better high speed RIB boats. And in the Baltic it's probably nothing compared to North Sea weather. If one could develop a large enough quad- or hexacopters that could be stored on all ferries and deployed to pick up people and lower them to ferry decks, that would help a lot. Hypothermia kills people so quickly there's often not enough time to send specialized help craft from far away.

exDM69 12y ago
> If one could develop a large enough quad- or hexacopters that could be stored on all ferries and deployed to pick up people and lower them to ferry decks, that would help a lot. Unfortunately, quadcopters can not be scaled up because the physics of multirotors doesn't scale nicely. The inertia of the blades goes up to the fifth power of the blade length. Double the blade length, 32x inertia. This would give prohibitive power and mass requirements. A lot of quadcopter research focuses on using multiple copters for lifting co-operatively because building big ones is not feasible. Multirotors are not particularly good in high wind conditions either. Even the specialized search and rescue helicopters (e.g. Super Pumas and SeaKings) had difficulty operating (and some were unable to operate) in the hostile weather conditions during the Estonia disaster. Short of carrying on board search and rescue helicopters (and trained crews) and and other hoisting equipment, there is very little that can be done to rescue humans from the sea in storm conditions.
- Gravityloss 12y ago
  Thanks for the good summary! I knew there was a limit to scaling, didn't realize it was the fifth power... On the other hand, if you're just lifting the copter itself and one person, it doesn't have to be the size of a full blown helicopter. Then again, its utility is limited then.

exDM69 12y ago

> If one could develop a large enough quad- or hexacopters that could be stored on all ferries and deployed to pick up people and lower them to ferry decks, that would help a lot. Unfortunately, quadcopters can not be scaled up because the physics of multirotors doesn't scale nicely. The inertia of the blades goes up to the fifth power of the blade length. Double the blade length, 32x inertia. This would give prohibitive power and mass requirements. A lot of quadcopter research focuses on using multiple copters for lifting co-operatively because building big ones is not feasible. Multirotors are not particularly good in high wind conditions either. Even the specialized search and rescue helicopters (e.g. Super Pumas and SeaKings) had difficulty operating (and some were unable to operate) in the hostile weather conditions during the Estonia disaster. Short of carrying on board search and rescue helicopters (and trained crews) and and other hoisting equipment, there is very little that can be done to rescue humans from the sea in storm conditions.

Gravityloss 12y ago
Thanks for the good summary! I knew there was a limit to scaling, didn't realize it was the fifth power... On the other hand, if you're just lifting the copter itself and one person, it doesn't have to be the size of a full blown helicopter. Then again, its utility is limited then.