Rotating Sail for Commercial Ships

[roverhi]

There are only two ways wind power will be used more extensively in shipping. One is a world wide government mandate that ships have to have the capability and use it. The other is doubling/quadrupling the cost of carbon fuel. The latter could be done with taxation or production limits, OPEC, on fuel.

All sail power commercial ships also have a limitation on where the ships can go with speed and where they can't. The clippers made fast passages by using the strong winds in the Southern Oceans and the trade winds. If you aren't located where those will speed a sailing vessel along they become very inefficient or would require almost total use of fossil fuels for propulsion. As they say, "Time is money" and having a sail ship at sea for weeks while a fossil fueled ship could make the same passage in days doesn't make for a good return on investment or use of manpower. If the Magnus Effect Sails could be built cheaply enough they might make sense.

What's not mentioned is how much thrust is generated in other than beam winds. Does the forward drive force effectively overcome the drag of the towers going to windward?? DDW, do the towers present enough frontal area to create an effective propulsive force. The ship rigged vessels were fairly efficient downwind as they could spread a very large area of canvas. Efficent in reaching conditons but hopeless to windward.

[SV Bacchus]

Originally Posted by Juho

The Magnus effect based Norsepower sails are just cylinders that are rotated by a motor. They just generate push from wind.

Ahhh, gotcha. Thanks!

[RaymondR]

We have ships which collectively travel hundreds of thousands of miles every year without releasing any CO2 - they are nuclear powered.

All this other stuff is corporate virtue signalling and will achieve nothing significant to delay the eventual depletion of hydrocarbon resources or the dumping of CO2 into the atmosphere.

Many of the users of this forum depend upon "renewables" as our primary sources of electrical power, and some adventurous folk even try to use it as motive power. As a consequence we are very familiar with it's advantages and disadvantages. Those of us who are still able to maintain even a nebulous connection to reality know that we will probably never be able to run a modern civilization with renewables.

Since many of us also use the wind as our primary source of motive power we are also very familiar with it's unreliability in respect of blowing in the right direction at the right time and with the massive tonnages modern sea trade carries the cost of unreliable wind power for mercantile marine purposes would be enormous.

Great dream, neva gunna happen. Putting our money into developing safe reliable fission and possibly eventual fusion is the only practical answer.