Rotating Masts & Wing Masts

WestMarine.com




For interest only, I'm doing some research on the benefits and construction of rotating masts and wing masts. I am looking for information on what this means to a cruising sailboat. I got some anecdotal evidence from an experienced sailor friend who had built one for his 27 foot catamaran. He believes it increased his performance by up to 30%. That is until his home made mast came down, fortunately it was insured but the insurance only covered a standard mast so there is no longer an opportunity for testing.

I would be interested in your comments on the following:

It seems pretty logical to me that in a storm a wing mast can be beneficial, if designed to be the correct size, in that it'll be the substitute for a storm sail. The question I have here is how practical is this in reality? i.e. how much will the mast be allowed to rotate and how to safely handle this in a storm.

Recommended reading, the cruising multihull has some information on constructing a mast and Gougeon Brothers on Boat Construction:

Practical hand construction techniques and ideas for making such a mast in carbon fiber, wood or retrofitting a second hand aluminum mast.

Some links on rotating spars and spars in general:

  • For those that are technically savvy here's a great pdf paper by Thomas E . Speer
  • Here are some in depth technical discussions on aerodynamics of masts.
  • A split boom rig, with some ideas on a base for a rotating wing mast.
  • Here's a video on construction of a composite mast by Bob Rast and Mark Isabell. Looks like fun! We don't grow up our toys just get more expensive.
  • Here's an article on wood mixed carbon fiber, a conversation with Bob Struble.
  • Here's an example of a wood carbon fiber combination
  • Here's an interesting option/product from Omer wing sails. Personally I'm not ready to give up on the for sail, and the modification necessary to accommodate an un-stayed mast are not very attractive.

Plans for wing masts:

Resources

  • For a basic understanding of angle of attack, camber, plan form etc. Here's a java app compliments of NASA
  • UIUC Airfoil Coordinates Database