Although I'm a huge fan of every kind of electronics
, I can see several problems with the webcam solution you ask right away.
1. As osirissail points out, the camera
will be all over the place because of the swing of the mast.
2. Most webcams have wideangle lenses, which makes them unreliable to measure things by just looking at the screen
3. My wifi connection gets psycho even when I run the microwave oven
. Now try to imagine it with a radar
dome, VHF antenna
and all the other kind of electronics
running while using it. I don't know about you but VHF or radar
are far more important for me to run constantly during a tight situation than a webcam.
4. Either you use bluetooth or wifi, the webcam will still consume energy, which means you either should run a wire for it or climb to the top of the mast every other day and change the batteries. Run the power wire, it'll include a more reliable type of connection anyway.
All being said, having a webcam up the mast is still a fun idea, but it should stay as a "fun idea" only.
What I would offer is pretty simple, attach a thin wire or piece of wooden stick on top of the mast horizontal to the ground. Go dead slow, if it touches the bridge, well, 5 gallon buckets are your best friends!!! Enjoy your trip.