Big Wind Sails


by Bob Dill - US3904 - February 1993

When the wind is over 25 MPH a DN is a real handful. We have used 'storm' sails which have about 40 square feet of area. They are way too big if what you want a manageable boat. In general, the power of the wind is proportional to the second power of the apparent wind velocity. This means that for a sail to be manageable at 30+ MPH wind it should be several times smaller than a full size sail.

The other problem small sails have had is the center of effort of the sail is too far forward of the plank. This gives the boat a nasty lee helm on a reach. This manifests itself either as having to hold the tiller to leeward on a beam reach or, even worse, when you are headed down wind at speed it is difficult to get the boat to round up.

I made an experimental 25 square foot sail that was well balanced, but still too big and it had other problems. This sail became three 9 square foot sails. Several of us tried them at the world championship this year on a windy day while everybody else waited on shore for the wind to settle down to reasonable racing conditions.

Hoisting the sail so the head is a little above the hound made the boat reasonably balanced. The boat was certainly not overpowered in a 30 MPH wind but it can still be sailed in wind as light as 15 (on good ice). The top speed of the boat was about 40 MPH on a reach with the wind in the mid to upper 20's.

A simple loose footed boom works well. I used 1 by 1 hardwood sticks with holes drilled in the ends to tie to the tack and clew and the respective blocks. The sheet set up is a two part system. A couple pieces of 3/16" low stretch line can be used to connect the head of the sail to the halyard and to extend the main sheet.

In addition to sailing on wild days, they should be great for neophyte sailors or young sailors on moderately windy days.

There was some interest at the regatta in standardizing these sails so we can informally race on 'too windy' days. 9 square feet may not be the optimum size and the current sails have way too much leach flutter. I have made 15 and 20 square foot sails. I will try them over the next month and will write a follow-up article for the spring newsletter.

If you have any thoughts or suggestions, please get in touch with me.


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