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Flying from a boat

herman2992

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I've had a couple of boating adventures. And a couple of glitches that I haven't seen mentioned elsewhere. Time to share.

I have a pontoon boat. Fair amount of deck space for takeoff and landing. But the a/c interprets seats, canopy and railings as obstacles and takes evasive action, so obstacle avoidance must be off.

Tried Dynamic Home Point last time, but DJI GO 4 APP reported "weak GPS" and wouldn't keep Home Point updated. Likewise with attempts to update Return To Controller. And yet plenty of Sats locked for stable flight and distance/direction tracking, radar plot, etc. Had I truly lost signal, a/c would have returned to original launch point and drowned.

Big one ... when tracking a boat, don't forget to disable Max Flight Distance! Everything was going fine, great footage of the boat, towing a tube with the grand kids ... when a/c stopped dead in its tracks. By the time I realized what had happened and got the boat stopped, the a/c was a good distance behind. Eventually reacquired.

Finally, landing. Even hand catching is a challenge when the boat is drifting in even a moderate breeze! Aircraft stays stable, but timing to grab it from a drifting boat with even light waves is ... Interesting.

Thoughts? Your own lessons to add?
 

msinger

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Tried Dynamic Home Point last time, but DJI GO 4 APP reported "weak GPS" and wouldn't keep Home Point updated. Likewise with attempts to update Return To Controller. And yet plenty of Sats locked for stable flight and distance/direction tracking, radar plot, etc.
The sat locks displayed in DJI GO were only for the GPS receiver within your Mavic Pro. If your mobile device is not able to get a good GPS fix, you'll either need to use a different mobile device (and one with an internal GPS receiver) or connect an external Bluetooth GPS receiver (like one of these) to your mobile device.
 

herman2992

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The sat locks displayed in DJI GO were only for the GPS receiver within your Mavic Pro. If your mobile device is not able to get a good GPS fix, you'll either need to use a different mobile device (and one with an internal GPS receiver) or connect an external Bluetooth GPS receiver (like one of these) to your mobile device.
Thank you! Makes sense.
 
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Robert Mitchell

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No issues with IMU initialization causing wonky takeoffs from the moving platform?

Just curious, as I want to try some kayak takeoffs and was worried about initialization from a moving surface.
 
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herman2992

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No issues with IMU initialization causing wonky takeoffs from the moving platform?

Just curious, as I want to try some kayak takeoffs and was worried about initialization from a moving surface.
No issues. Stable hover. Proper control responses. I assume those are signs of solid IMU initialization.
 

Mossiback

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No issues with IMU initialization causing wonky takeoffs from the moving platform?

Just curious, as I want to try some kayak takeoffs and was worried about initialization from a moving surface.
The biggest problems with launching from a boat are:
• Magnetic interference
• Waves
• Boat movement

Hand launching is mandatory from a boat if there is even the slightest up/down wave motion. As soon as the props are started the Mavic is flying. The reason it idles on solid land is because no more power is needed to maintain it's position. As soon as there is a sudden drop (as from a wave) the motors will rev up to maintain it's position in space. Then it will remain stationary while the moving boat railing, rigging, people, or other objects could conceivably run into it.
 

herman2992

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The biggest problems with launching from a boat are:
• Magnetic interference
• Waves
• Boat movement

Hand launching is mandatory from a boat if there is even the slightest up/down wave motion. As soon as the props are started the Mavic is flying. The reason it idles on solid land is because no more power is needed to maintain it's position. As soon as there is a sudden drop (as from a wave) the motors will rev up to maintain it's position in space. Then it will remain stationary while the moving boat railing, rigging, people, or other objects could conceivably run into it.
And when hand launching from a boat, check the drift direction. The aircraft wants to stand still, and the boat (including you!) may drift straight into the rotors.
 

Hayabusa

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The biggest problems with launching from a boat are:
• Magnetic interference
• Waves
• Boat movement

Hand launching is mandatory from a boat if there is even the slightest up/down wave motion. As soon as the props are started the Mavic is flying. The reason it idles on solid land is because no more power is needed to maintain it's position. As soon as there is a sudden drop (as from a wave) the motors will rev up to maintain it's position in space. Then it will remain stationary while the moving boat railing, rigging, people, or other objects could conceivably run into it.
This is great info. I would have never thought if that.
Got to love this site.
 

hawk3907

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I always hand launch from a boat.
I also always land the drone on my wifes hand. We have practiced this several times in the yard to get her comfortable with it.
 

Mossiback

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Landing on a boat can get interesting, due to all the motion. I have not tried this technique, but it looks interesting.
 
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hawk3907

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This is pretty interesting. They looked like they were moving at a descent speed too and still pulled it off. I cant imagine a hand landing would have been possible without the string.
 

Storyline

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Not sure if I fancy the string attached. I know in theory it should be blown down by the downdraft but it must have potential to get 'involved' with the props.
 

Storyline

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.....
Hand launching is mandatory from a boat if there is even the slightest up/down wave motion. As soon as the props are started the Mavic is flying. The reason it idles on solid land is because no more power is needed to maintain it's position. As soon as there is a sudden drop (as from a wave) the motors will rev up to maintain it's position in space. Then it will remain stationary while the moving boat railing, rigging, people, or other objects could conceivably run into it.
I have not had my Mavic long enough to know all its features but is it not possible to dumb it down (by turning sensors off) to get round this problem or would that render it unflyable ?
 

Mullheliflier

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I was recently asked to film from a boat commercially. I declined as I felt the risks were too great.
 

shark4985

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I have launched and landed from a boat many times, all by hand but only for lack of a better option. Until you have done it, it sounds easy. The boat always seems to move more when you are trying to land your MP. A few key points for anyone trying this for the first time:
-Keep in mind the relative motions of the boat/ MP. Even if you think the boat is not moving, it is unless you are tied to a dock. As soon as you launch the MP, it will hold GPS position, and the boat can very quickly move into the MP. Always launch from the trailing side of the boat based on which way it is moving so the boat moves away from the MP.
-Look up before you launch. The first instinct is to gain altitude, make sure you are clear of outriggers, fishing lines, rods, and any structure of the boat.
-It takes two to land. I have done it by myself, but it took several attempts. Again, those calm, 1 ft seas mean cyclic "altitude" changes relative to the boat at varying frequency while you are trying to not lose a finger or a drone. Almost took a prop to the face. Have someone catch while you shut it down.
-Check your setting for signal loss, and smart RTH. If you don't, the MP will turn around and fly back to where you took off from when the battery gets to about 50% or you lose signal.
-Give yourself significantly more margin on your battery for landing.
-Go on youtube and search for boat drone launches/ landings and learn from others who have failed before you.
 

herman2992

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I'm thinking of crafting a piece of canvas boat cover for the front three or four feet or so of my boat. Stretch out across, snap into place on both sides, to create a large, obstruction-free takeoff & landing "trampoline". Should make landing a breeze (pun intended) on a 4' x 8' canvas rectangle.
 

Mossiback

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Not sure if I fancy the string attached. I know in theory it should be blown down by the downdraft but it must have potential to get 'involved' with the props.
The string has to have a weight attached to keep it out of the props and make it easier to grab. The downward sensors should be disabled (they have problems with water anyway) to avoid problems.

I have not tried this trick, just saw the video and thought it would work.
 

Mossiback

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I have not had my Mavic long enough to know all its features but is it not possible to dumb it down (by turning sensors off) to get round this problem or would that render it unflyable ?
Turning off the OA sensors will not change how the Mavic perceives motion.
 

Storyline

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I'm thinking of crafting a piece of canvas boat cover for the front three or four feet or so of my boat. Stretch out across, snap into place on both sides, to create a large, obstruction-free takeoff & landing "trampoline". Should make landing a breeze (pun intended) on a 4' x 8' canvas rectangle.
That is a good idea. The main problem we have is that the ends of the boat are out because of the fore and back stays (sailboat). The only practical place is the cockpit with the boom lashed over to one side. There is a lot of metal and electronic around though. The other thought I have had is to use the rubber dinghy we have. If i take the seat out it has an inflatable floor that has maybe 2.5 x 4' of clear space. I have also got one of those round pop-up helicopter landing pads that could be lashed somewhere.
 
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gnirtS

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From a boat i'd class hand launch and hand catch landing 100% essential. Its the only guaranteed way to keep it away from potential wires, interference, metal and bits moving as the boat drifts hitting the drone.