RE: Harness Safety Question
Nick and Thomas have given you some good ideas here.
MOst of all you need to avoid panic. Best way to do that is as Nick suggests.
I recommend that sailors at your skill level actually "practice" getting themselves unhooked from the harness with the sail on top of them.
Do this ""practice" in shallow water, where you can simply stand up to get some air if you have any problems. You can make it safer if you find someone learning the same skills and you have them be your "spotter" until you have a "learned response" pretty well dialed in.
Then you can return the favor and spot for them as they learn the same skills.
If you practice getting unhooked and the best way out from under your sail (usually following the boom to the mast is the shortest distance and the easiest/fastest way out) when you find yourself under your sail in the future you will (without any panic) simply use your back hand to clear the harness line off the hook, then follow your front hand along the boom and out from under the sail.
Also, a Nick and Thomas suggest, you need to kep a sharp eye upwind and ahead to "anticipate" whether you're going to have to deal with a gust or a lull.
The strategies suggested should serve you very well.
If you fall forward, on top of your sail, do not let go of the bbom.
Better to bend your boom than fly uncontrollably into the sail/mast/boom with your out of control body.
As Nick suggests, hold onto the boom, keep your feet/toes on the board, and ride it down to the water.
Practice is more important for getting out from under your sail quickly,
so work on that first.
But you also need to work on riding the boom down in leeward falls and how to turn catapault type falls into simple leeward falls.
You can always simply "bail out" but this has some risk involved as well. Boards have been known to sail for quite a ways without the sailor so you need good swimming skills.
Also, your board and rig become somewhat an "unguided" missle, and can do damage to the board/rig or to others sailing nearby if you simply "let go".
Try to learn where the "point of inevitability" is for each type of fall, and learn to ease up on your sheeting angle, fin pressure, etc. BEFORE everything comes apart.
Hope this helps,