Nope, L'Hydroptere's speed is not ratified by the WSSRC, but without question, just flat hauling butt.
The number listed is a peak speed and unfortunatley, that does not qualify as a record. They have to maintain the speed and the average over a minimum 500 meter regulated course is what will get them a record.
Epo, you are right, the kiteboarders and some windsurfers have also clocked speeds that high for momentary values. The world record for 500 meters is currently held by a French kiteboarder at 50.57 knots. I believe that the speed is still pending final ratification from the WSSRC, but the record run was supervised, on-site by representatives of the WSSRC, so it should be just a matter of a short time for the official deal to fall in place.
The part that completely amazes me is that all the wind force to get going that fast (40-45 knots) is being pushed right through the boarders body. No winches, no tie-off points, just one studly dude (or dudess) hanging his/her cheese waaaay out in the wind. By the way, the fastest women's speed sailing record is Sjouke Bredenkamp with a posted run of 45.2 knots.
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