Hovering question....... please dont laugh

[Meta4]

I’m sitting on the fantail of a cruiseship which is underway....... aprox 20mph

What you are contemplating is much more complex than you imagine and highly likely to lead to the loss of the drone.
Just a few of the issues to consider:
Ships are made of steel. Don't launch from steel surfaces or you'll have compass problems - hand launch.
Ship speed would make launching difficult - launch from a sheltered location
Winds .. if the ship is sailing into a >10 kt headwind you may never be able to catch up after launching
Home point/battery. The mavic will get to a point where it calculates it only has enough battery left to return to where it was launched and goes RTH into the distance?
You need to update the home point during flight to prevent this.
There is no dynamic home point.
Landing - you will have to hand catch but at 20+ mph it's going to be very, very difficult - a big landing net might be your best bet.

The offshore environment is totally unforgiving, one small mistake and you have one less drone.
You need to be able to do everything necessary without having to think about it.
I fly offshore but I can get the skipper to drop back below 5 knots for launch and landing.
Because I understand what's involved, I'd never consider doing what you are thinking about.
If you want to shoot cruise ships, do it from shore:

 

[BrianS]

A lot of times cruise ships speeds are reduced in order to save money and to arrive at port according to schedule. I’ve seen 10-12 mph speeds on my GPS many times. I thought about asking if I could do a late night/early morning flight when no one is on deck. A cruise ship sailing on a clear night with a full moon and a port of call in the background would be cool video! I do a Panama Cruise this Spring.

 

[dronerdave]

What you are contemplating is much more complex than you imagine and highly likely to lead to the loss of the drone.
Just a few of the issues to consider:
Ships are made of steel. Don't launch from steel surfaces or you'll have compass problems - hand launch.
Ship speed would make launching difficult - launch from a sheltered location
Winds .. if the ship is sailing into a >10 kt headwind you may never be able to catch up after launching
Home point/battery. The mavic will get to a point where it calculates it only has enough battery left to return to where it was launched and goes RTH into the distance?
You need to update the home point during flight to prevent this.
There is no dynamic home point.
Landing - you will have to hand catch but at 20+ mph it's going to be very, very difficult - a big landing net might be your best bet.

The offshore environment is totally unforgiving, one small mistake and you have one less drone.
You need to be able to do everything necessary without having to think about it.
I fly offshore but I can get the skipper to drop back below 5 knots for launch and landing.
Because I understand what's involved, I'd never consider doing what you are thinking about.

Yeah I was wondering about launching off metal. Guess it would be easy to test... fly it out of the back of a (moving) pickup truck. Not that I'd try it.

 

[Bwoody321]

It would be down to the velocity of the two objects heading towards each other I’m guessing

 

[4wd]

There are a few videos exploring what happens flying in unusual situations, tech has moved on and they are better now at using downward sensors if GPS is not available.
There are other questions come to mind like maybe flying in a lift?

A slow moving boat is feasible otherwise a very bad idea I think, but an interesting thought experiment.

 

[Mossiback]

A lot of times cruise ships speeds are reduced in order to save money and to arrive at port according to schedule...

They also increase speed to stay on schedule if there is any delay leaving the last port.

 

[Kilrah]

OK, now I'm curious about the opposite end of the ship. Since the drone will stay stationery based on GPS, what will happen if you take off from the front of the ship? I assume the drone will stay still, but will the sensors do anything to try to prevent the superstructure of the ship from running into it?

It will stay still with regard to earth and the ship will ram into it. Several have made the mistake already...

To take off from a moving boat you want a machine that you can disable positioning on (aka atti mode) and understand well what to expect.

 

[Jalal]

I’m sitting on the fantail of a cruiseship which is underway....... aprox 20mph
I launch and hover my drone at ....... say 50 feet.
Will the drone be left hovering in place as the cruiseship moves away OR will it stay in place ......... hovering over me and the fantail

I would say that it will be left behind

 

[vanderzyde0]

There are several videos about this subject here is one with a drone in a moving van

 

[StevieJ]

Similar kind of question if I may... if I take off and hover at say 50ft.. and then fly over a quarry where the quarry floor is 400ft below... what happens to the drone? I have a Mavic Air. Does the height of the drone then become 450ft.. and now flying higher than permitted?!

 

[knewt]

I would say that it will be left behind

I wonder how surprised this guy was to cuddle up with his Phantom that night!

 

[calmar81]

Holy c***!!!

 

[DanMan32]

Reported height is relative to takeoff point.
If you hand launch for example, your reported height will be off by about 3-5ft.

 

[vanderzyde0]

Reported height is relative to takeoff point.
If you hand launch for example, your reported height will be off by about 3-5ft.

How does it “know” what it’s height is when it takes off? GPS?

Anyone actually have real life experience flying off a cliff?

Why doesn’t it update it’s altitude when the terrain changes?

 

[vanderzyde0]

Holy c***!!!

This is pretty extreme and demonstrates the ability to fly in bad weather and wind when you know what you are doing (note the flight is with the wind so the drone doesn’t have to fight the wind to come back to the ship)

 

[calmar81]

This is pretty extreme and demonstrates the ability to fly in bad weather and wind when you know what you are doing (note the flight is with the wind so the drone doesn’t have to fight the wind to come back to the ship)

Sooo good! Thanks

 

[Inspirephil]

Oh sheet........ then I would need to catch the ship to retrieve my drone now THAT would be awsome video........ for sure

Good luck
What you really need is the GPS remote module and then enable Dynamic Home Point in the general settings. If you do that then your drone will update its position every 20 seconds and track the remote control more precisely. The GPS remote module is only $25 on Amazon. I use it when I have to fly while I’m driving my car.

 

[knewt]

This is pretty extreme and demonstrates the ability to fly in bad weather and wind when you know what you are doing (note the flight is with the wind so the drone doesn’t have to fight the wind to come back to the ship)

Def knows what he (she?) is doing, but they needed to work that Phantom pretty hard, as from the launch and the sails that wind was strong enough and crossed enough to be close to the limits.

I’d love to know what his (or hers) expectations of getting it back were. I’ve done a few relatively high risk stuff from drones and RC and it plays tricks with your head. You end up convincing yourself that the risk is acceptable, and, strangely, it usually is. Which suggests our (my) risk perception usually has a lot of tolerances built in.

Just to be clear, any risks I’ve taken are on top of mountains with consenting, likeminded adults and any risks were financial rather than personal safety!

 

[vanderzyde0]

I think the limit for wind is relative to what you are doing. In this case the wind was pushing the sailboat and the drone along at the same rate.

Issues arise when people are stationary and fly WITH the wind out on their flight then have to fly INTO the wind to RTH.

This video is a good example of relativity - both objects in relation to each other were consistent in movement and direction. the drones relative speed to the boat was almost zero while both the boat and drone were being moved along by the wind at several knots judging from the sail and bow splash.

This was a very competent pilot to do this in that weather and wind.

 

[knewt]

I think the limit for wind is relative to what you are doing. In this case the wind was pushing the sailboat and the drone along at the same rate.

Issues arise when people are stationary and fly WITH the wind out on their flight then have to fly INTO the wind to RTH.

This video is a good example of relativity - both objects in relation to each other were consistent in movement and direction. the drones relative speed to the boat was almost zero while both the boat and drone were being moved along by the wind at several knots judging from the sail and bow splash.

This was a very competent pilot to do this in that weather and wind.

The wind is, I guess, 30 degrees off from directly behind the yacht, so they are not being naturally aspirated at the same speed. The drone does not have a dagger board. The strength of the wind is, I guess, f’ing strong. When you see the drone downwind you can see the props, ergo it’s pitched forward like buggery trying to make headway.
So, whilst you are right in theory, in this instance the pilot was taking a calculated risk about the relative crosswind versus top speed of the drone.