## Jun 2 Rotor Ships (an article by a teenage me)

Long ago I used to use facebook to host notes on things. Most of it is unreadable, but I liked this one. I present it only minimally edited from its original form and with the original pictures. The edits took out the word "basically" from the start of many sentences and also changed some of the grammatical choices that 19 year old me was trying to introduce into English. Honestly, teenagers.

"I just read something interesting about Rotor Ships (also called Flettner Ships) and I've spent my last half an hour thinking about sails. They were a new type of ship built in the 20s, but were scrapped because of more troubling things (why does the war have to spoil everything?) so they were never really taken advantage of. To understand them, you first have to understand the Magnus effect, so I'm afraid we're going to have a quick physics lesson, filled with pictures from paint.

The Magnus Effect generates a resultant force on a rotating object moving through a fluid. Think about a football which is spinning through the air, this is the effect which makes its trajectory bend, the fluid in this case being the air. The maker of these ships decided to make two huge rotating towers on top of an old retired ship. They were about 3 meters wide and 15 meters tall and had to be turned by engines. So in effect they were ships that still required fuel, but the idea was that they would be made more efficient than just linking up the engines to a propeller by using the wind.

He originally wanted to link the two towers on the ship up to one big motor, but instead decided to have each linked to their own motor, so they would be able to turn on the spot by varying the speeds and directions of each tower.

A benefit over using normal sails, is that the ship could sail much closer to the wind. A normal ship can manage to go at 45 degrees from the wind, while these new ones could manage 20-30 degrees.

Unfortunately, they proved to be slightly less efficient than traditional motor ships and they were far too difficult to maneuver (one of them crashed into the pier, both on departing on its maiden voyage and arriving at its destination) so they were dropped.

But it has me thinking, and I think I've come up with a ship propulsion design, which is much easier to understand, would still be able to sail much closer to the wind than a traditional sail and doesn't require any fuel like a Flettner ship. Here is a picture:

There are two shots of it: one from above, and one from the side, but in 3d. The wind direction is green and the force on the boat is in red. The mast works like a waterwheel, with buckets to catch the wind all around it. The little red lines would essentially be string, so each bucket fills when it is red side to the wind, but collapses into the mast when the wind is on the wrong side, thus increasing efficiency. The whole mast turns and can be connected to a drive shaft through bevel cogs in order to drive a propeller at the back of the boat. Imagine a big waterwheel attached to the mast of a boat, for harvesting wind.

The beauty of this design is that it would work whichever way the wind is coming from (although you might have some problems going directly upwind) so it would need very little skill to use. You could have as many masts as you wanted, all lined up the centre of the boat, as they would pack in quite neatly, and the whole way up the mast could be massive buckets.

If you made the masts too tall then the whole thing would blow over, but you could solve this with the use of a waterwing which would automatically fall into the position against the wind to prop the whole thing up. Or you could use your own weight to balance it, like in a normal sail boat.

Anyone want to make me one? I have images of me dressed as a pirate swerving among the punts in this crazy boat."

Afterword by 2017 Alaric: Well I never made one, but I did spend a lot of time dressed as a pirate. Something which occurred to me after I wrote about the ship design was that the ability to have the wind come from any direction and to not have to aim anything would be useful for driverless boats. If speed wasn't an issue you could set these off on a heading and they would sail along without need for power or steering (other than correctional). To have fleets of tiny bucketships delivering packages doesn't sound efficient, but it does sound beautiful.