Mast Rotation controls and spinnakers

Rob from Canberra writes:

I am setting up the boat for single handed sailing and I am thinking about the mast rotation.  Do you use the quick release for the mast rotation?  Do you release the mast on the downwind?

Anyway, I can’t figure a good system for the quick release mast rotation for single handed.  It is all set up around the mast base by default, and that is not a part of the boat I want to be needing to get to during a spinnaker recovery or launch.  I thinking that the best idea may be just to not use it…

Beau writes in response:

You MUST release the mast rotation when you are carrying the spinnaker. Its fine in the light breeze but in the heavy you will stress and possibly break the mast. The reasoning is that the spinnaker pulls on the un-supported section of the mast. This “rotates”the mast around the hound where the diamonds and stays support the mast. With the mast rotated to 90 degrees the mast is pulled by the spinnaker sideways against the “thick” section so its strong enough to handle the sideways load of the kite. The Forward/back load is supported by the mainsail so that’s why its important to have main sheet on to support the mast and the mast rotated. In 12 knots it makes little difference with the mast rotation on or off. But in a blow the combination of Cunningham on, Mast not rotated and mainsheet off took out four masts in the gusts of South West Rocks this year…4! two F18s one Nacra 5,8 and a Nacra 4.0.

The masts broke when the bows stuffed, max load was on the kite and generally the main was let off. If you look at your mast with the kite up you will see how much it bends above the hound if you let out the main. The combination of the fat mast section left and right and the main sail forward/back supporting the mast make sure there is minimal mast bend.

Not only is the snapping or permanent bend an issue but if the mast does bends bending also releases kite luff tension and the kite loses shape and becomes a bastard to trim…and its slow.

Finally the mast rotation control points, some folks have gone away from the quick release to a continuous system and then finally settled on a combination of a quick release on the mast base and a continuous system with a take up under the trampoline.

If you forget the quick release you can release from the cleat on the hull, or if it is nuking you can just uncleat the control line from the hull. With it being continuous you can re-cleat the rotation on the opposite hull if you forget to re-cleat it after releasing it. Re-cleat the leeward sided by pulling the take-up through enough that it cleats, same as you do on the Cunningham and Jib sheet. I went back to the quick release after racing the F18 national where we found that mucking about after a bottom rounding to get the mast to the right rotation spot was wasting precious time and distracting us from getting the boat back in the groove quickly upwind.

Most important….dont let the main off downwind in a blow, The harder it is on the better, it will support the mast and prevent a pitchpole as the head will not open up. Get the main on after the bear away before you start hoisting, steer with your foot. Yes its twitchy but in 20+ but it’s the only way to keep the bows up.

Hope that helps