I went sailing after work on Friday and this happened.
Here's the description of the event that I posted on the iwindsurf.com forum.
I was chasing the Florida seabreeze today with my formula board and 9.5 ezzy cheetah. Mostly I was shlogging, but whenever a 10 knot "gust" rolled through I'd pump to plane for a bit.
I was sailing along in a particularly good gust, maybe 11 knots, when "POW!" - I was in the water. The bottom half of my 490 cm 75% carbon Gaastra mast had snapped about a foot above the boom.
I de-rigged on the water, lashed the rigging in a bundle down the centerline of the board, and started SUP'ing back to shore using 2/3 of the mast as a paddle. Fortunately I was only about a mile offshore and the launch was almost directly downwind. It took me about 30 min to get back. Nothing besides the mast broke or sank, thank goodness.
Anyway, I'm not real surprised that the mast broke. About two years ago when I first got it I heard a little "click" when clamping the boom on tightish. (Btw- with the chinook carbon formula boom head there is a very narrow margin of error between tight enough to not slide down the mast and loose enough to not crush the mast. Beware) The damage spot must have been minor at first, but I think it probably grew a little bit every time I sailed. I didn't use the 490 much for the two years I lived in MA, but it was the mast I most often after I moved back to Florida.
If anyone wants the top of the mast, let me know.
These things happen. I'll be getting a used 490 from Ace Performer in Ft. Myers so I can get back on the water this weekend.