ROBOSAIL Open 40 Racer

[Fonx]

RoboSail Open 40 Racer, 150K öirosid

As i see in picture this boat has no rigging, i was wondering doesn't so tall mast break in stronger wind.

[Eric Sponberg]

Originally Posted by Fonx

RoboSail Open 40 Racer, 150K öirosid

As i see in picture this boat has no rigging, i was wondering doesn't so tall mast break in stronger wind.

Interesting design. To answer your question, no, a properly designed and engineered mast should not break. Any mast, free-standing or stayed, is designed to the maximum righting moment of the boat, plus a safety factor. As stronger and stronger wind blows, the boat heels more and more until it reaches that heel angle where the righting moment is the greatest, usually somewhere between 45 and 60 degrees of heel. Any more wind and the boat will continue to heel over, but the righting moment is less--eventually goes back to zero at what is known as the vanishing angle of stability (AVS) or also known as the range of stability. So for any given boat design, there is always a maximum load that the boat will ever see, at this maximum righting moment. The more sail area there is, the less wind speed is required to reach max. heeling moment, but that max. heeling moment does not change. It is easy to calculate, so it is easy to find the maximum load for the rig. Design accordingly, and the mast will behave properly and last a long time.

Eric

[kenJ]

For more information on the rig see:

http://www.stadtdesign.com/products/SwingRigInfo.html