i just pour hot water, not too hot tho down the top of the mast and clamp a boom on where it normally goes and twist it round never had an issue but then again never had sand down the top of my own mast 
also the two booms work well as a last resort
one end tied to tree
other end tied to XD / XE falcon, Saab, PT Cruiser or Ford Taurus, driven by mother-in-law at high speed tawards cliff edge
Tried your method P.C_simpson on a mast I use a lot and that has always been a fair B...... to pull apart and it worked first go.
Unfortunately I can see a new windsurfing injury starting to appear.I wonder if WWA insurance covers being struck by a mast in the carpark?[}:)]
