That was a motor boat and it was easy to just "park" it and fly from it. But what about flying off a sailboat? And that's exactly what we got to do this weekend in the San Francisco Bay Area. There are a few things that you need to keep in mind. One of the most important - this boat continues to move and move and move. More info in the Tips and Tricks section.
Why does this matter? When you start up your multirotor it connects to the GPS satellites and locks a location as HOME. That is the spot it will return to if it looses signal. This is also the spot it will start counting distance.
HOME is not where your radio is, but rather where the multirotor determined that "I have enough satellites to locate this spot and make it my home".
So as you keep flying and following your sailboat and the sailboat is doing a straight line, going further and further away from that home location, the distance, obviously, increases from that point. The multirotor doesn't know that you are moving along. And at some point you will reach that 5,000 feet and it will be like hitting an invisible wall. Your multirotor will just bounce against it and stay at that location while you keep traveling.
If you have ever been on a sailboat, it is very maneuverable but it takes time to initiate and do a 180 degree turn. That's what you will have to do. If you keep going then at some point the distance between your multirotor and the radio will be too big and you will loose connection. What will happen next is almost a certain disaster; the flying machine will turn around and fly 5,000 feet back to where it had recorded its home location. In essence it will fly away from you all the way the opposite direction. Good luck trying to catch up to it.
I will address all of this in the "Tips & Tricks" section.
- Lift off with the wind or to the side
That means try to launch from the back of the boat. While you go up, the boat will move away from you. Even better if you can launch from the back and fly to the side. This way you will clear the boat, the mast, the sail and all the lines.
Taking off from the front of the boat means you will have to stay ahead of the boat and that can be a challenge right there.
- Have somebody hold your machine
You won't find a place to put it so just have it hand launched. Same for landing. Make sure this person knows the difficulties with this. Have them wear safety goggles.
- Landing is not easy.
Keep in mind you are moving, the boat is rocking and now you have to bring back your machine. Don't wait until your battery power is at 30%. You want to have enough power for a few landing attempts.
If you know that the sailboat is not faster than the top speed of your machine, then you can approach from the backside and slowly catch up. But again, if the boat is faster than your flying machine, you will have a problem getting behind!
Fly along side the boat and slowly get closer. Try to get it just slightly above head-lever and have your helper grab it out of the air.
Update August 4th, 2014:
We got a note from our friend Archer with MultiRotorCam. He made a very good point. The only thing I would add to this: If you are not an experienced pilot, you may not want to practice flying ATTI mode on shore first:
Archer, thank you:
"Thanks for that! I'd like to throw out one incredibly important point to this flying-off-a-boat information (which I gather you are unaware of). The max radius limitation is actually easily overcome by merely flying in ATTI (non-GPS) mode. Yup. I've tested and confirmed it on my own sailboat operation off the stern of the O'Neill yacht. You can confirm this information on page 26 of the Phantom 2 User Manual (v1.1)."