Great stuff Jazzz even though I haven't tried it yet. How do you safely waterproof your Android whilst allowing touch screen?
I only hope it works off-line and that race regulators won't ban it.

thanks alex! there are some water resistant devices as i mentioned earlier and also there will be some new (samsung, panasonic, toshiba, etc..)
the question about mounting device on the arm is still open - i'm using custom made mount allowing to use touch screen. there are also some arm bands exists(including xperia active's one that goes with phone) but they are pretty much suck cause you can control device only through hardware buttons. on the other hand software do not need any user input except navigation part.

yes, it works offline but for another reason - to save battery ))
about real actual race - you only need your speed and maybe course from device. that's all, the rest of info must be in your head. =)

If you are heading for the windward buoy (because say, you've risked a different option than the pack), on your own out there, with no-one nearby to let you how well you are doing, VMG appeard to me as vital.
Two years ago, I asked Bruno Sroka, who was at the time winning nearly every leg of every race, why he wasn't using GPS. He said he'd be distracted...
Same answer from many top racers...
I believe GPS will eventually part of every racer's gear, provided the rules allow it. However I also think the rules should not allow it; the winner should be the racer with the best flair, not the best technology. See how Formula One have become boring as a result of a technology race.

Hi alexrider, I have a Sony Ericsson Xperia X10 which is certainly not water proof (or even water resistant!). I too have developed some software for my phone and have had no trouble at all by simply vacuum sealing the phone with a typical home bag sealer. I think it cost around $80 for the sealer and it is also great for storing left over food. I have no problem using the touch screen through the plastic.

Do you cut the bag every time? Or you can charge it without cables?

About wind shifts - your device may indicate that you're going on the wrong side but it's already too late because you already there (two extra tacks + some time to realize that your VMG is poor) same thing if you're on a lifted leg.
imho the most vital thing is to feel that you're going with the right speed and to the right direction in certain conditions. All this gps devices may be very useful while practicing, testing new gear or setup, but on relatively short races brain works much faster.