Launch and return to boat

[Hobbo]

Hi I'm planning an outing on a friend's 50 foot aluminium boat - plenty of steel as well no doubt. I expect I'll be able to lock into ~10 - 15 satellites but not sure about compass calibration. If I have clear viability; no wind etc am I going to be able to operate without risk of rogue flyaway etc - I'm not for example wether the controller will allow me to fly if steel upsets the compass? Thanks

 

[Mossiback]

Go 4 should warn about compass problem and advise you to move takeoff point. Make sure boat is not moving at takeoff.

 

[RTKD]

I know this is a little extreme, but I would practice taking off and landing by hand first. Landing in your hand even more so. The few times I've done it I was glad that I was comfortable landing in my hand because the boat is always moving, and flat open spaces are usually minimal.

The other thing to make sure of is that you have return to home set to updating, and that the craft is set to hover as long as it can (and not auto-land). I would avoid using return to home at all, and just be extra careful.

 

[Hobbo]

Go 4 should warn about compass problem and advise you to move takeoff point. Make sure boat is not moving at takeoff.

So if I get the compass warning, do I have the choice to takeoff anyway - or won't it allow me to takeoff at all? I won't be able to move anyway to calibrate as the whole boat has plenty of metal. As the boat will move, I won't be using RTH and will be flying manually with clear line of sight. There's plenty of deck area for landing or I can hand land if need be.

So I suppose it comes down to ... should I or or in fact, can I fly, if the compass hasn't calibrated?

 

[Mossiback]

Do not fly with a compass problem. Learn how to hand launch and land. This can be tricky if the boat is rocking at all. Wear gloves.

 

[Hobbo]

Tx Mossiback.

So you're saying there's only 2 alternatives. Either:
- I find a spot on the boat that allows me to calibrate the compass; or
- I don't fly because the risk of a flyaway is too high if I get compass error

(I'm OK with hand launch and land)

 

[Rockin2climb]

I believe if you calibrate the compass on land (away from the metal), as long as you set your home point to your moving location, you should be able to take off on the boat. I think the only purpose to calibrate the compass is to set it to your relative location. Your home point should be updated from the location that your take it off from and keep updating as your body moves.

****, that's a big boat!

 

[Hobbo]

Hi R - I won;t be relying on RTH so won't be needing to update my home point (if in fact that's possible - I thought RTH was specifically return to the take off point, NOT where you subsequently have moved to ?). My Q is:
- can you in fact take off if the RC is showing"compass error"; and
- if so, is it a stupid thing to do?

 

[Mossiback]

...So you're saying there's only 2 alternatives. Either:
- I find a spot on the boat that allows me to calibrate the compass; or
- I don't fly because the risk of a flyaway is too high if I get compass error...

Not quite. Definately do not fly if you have a compass error and unless the boat is still only hand launch/land. There are many drone crash videos involving boats and you could learn from their mistakes.

Specifically regarding the Mavic Pro, if the compass is affected by some metal at launch it becomes confused once it moves away from the metal resulting in loss of control.

Once the props start turning it considers itself flying and will try to maintain its position. If it detects a sudden up or down movement the props will spin up to hover and maintain its GPS position. If the boat is moving and the Mavic is stationary crashes may result.

I still believe your best chance of success is hand launching/landing.

 

[Meta4]

So if I get the compass warning, do I have the choice to takeoff anyway - or won't it allow me to takeoff at all? I won't be able to move anyway to calibrate as the whole boat has plenty of metal. As the boat will move, I won't be using RTH and will be flying manually with clear line of sight. There's plenty of deck area for landing or I can hand land if need be.

So I suppose it comes down to ... should I or or in fact, can I fly, if the compass hasn't calibrated?

First, why would you want to calibrate the compass?
It's not necessary and should never be needed unless you modify your drone.
Forget about calibrating the compass.

Next, flying from a boat is tricky and it's an unforgiving environment.
One mistake out there and you go home with one less drone than you took out.
You need to be proficient at all the procedured you'll use on the boat and have practised on land.
Out on the boat is not the place to learn new tricks.

You need to be good at hand launching and catching.
You also have to be able to reset the home point withing having to think about it.
The important thing is to prevent your Mavic from wanting to go back where it was launched because it thinks the battery level is only just enough for that long trip back.

ps .. although people keep saying "metal" what they mean is iron or steel.
brass, copper, aluminium, lead, zinc etc won't have any effect on your compass.

 

[JDawg]

"First, why would you want to calibrate the compass?
It's not necessary and should never be needed unless you modify your drone.
Forget about calibrating the compass. "

You know a lot more about this stuff than I do but you lost me. My Air has me calibrate the compass from time to time. Also I have seen more crashed drones from people not paying attention to the fact their drone was not facing the way the display showed that it was and they did not fix (calibrate) before take off. Am I getting confused with the terminology?

 

[Mossiback]

... My Air has me calibrate the compass from time to time. Also I have seen more crashed drones from people not paying attention to the fact their drone was not facing the way the display showed that it was and they did not fix (calibrate) before take off...

Full disclosure: I only have MP experience and have never had the display and MP not agree on direction. I have had rebar in concrete affect it and Go 4 advised me to find another launch point. My advise about this problem is based on postings of those that have.

I have read that the Air needs compass calibration more often but do not do it to fix a display vs actual direction. The display is off because something at that spot is causing the error. If you calibrate to match the error and launch, then move away from the error cause, the compass calibration will be off leading to loss of control. Try instead moving to see if the deviation is corrected. This will be hard to do on a boat but you mentioned it was a large boat.

 

[JDawg]

I think for sure the Air needs calibrated more. I was in the middle of a parking lot on a mountain ski resort and in a field this weekend and had to recalibrate both times. The two spots were hundreds of miles apart but I have read that should not matter. For the Air it is simply a matter of rotating the drone horizontally and vertically so I don't mind.

 

[DanMan32]

So, it isn't just M2 that will tend to require calibration every 30 days or 30 miles.

As for home point. Yes, home point is set on launch, assuming good GPS. You can update home point manually to current AC position, or RC position if your mobile has GPS.
There's also an option for dynamic home point where home point updates periodically automatically.

 

[RTKD]

I do not trust return to home,
I would not use it on my drone.

I would not use it on a boat
I would not use it with a goat.

I touch the button and I pray
My mavic pro won't fly away

I do not trust return to home
I would not use it on my drone

 

[swooshdave]

My Air will not take off if it has a Compass Calibration warning.

You can take off and fly from a boat but the pucker factor is going to be high. A 50 ft boat is huge so if you can't land on that thing you probably have bigger problems.

I can't wait for the video... or the crash story.

 

[mjbok]

Hi R - I won;t be relying on RTH so won't be needing to update my home point (if in fact that's possible - I thought RTH was specifically return to the take off point, NOT where you subsequently have moved to ?). My Q is:
- can you in fact take off if the RC is showing"compass error"; and
- if so, is it a stupid thing to do?

An air won't take off with a compass error.

RTH is also where it will go if you lose connection. If it is updating it will RTH much closer to where you are when you lose connection so you have a better chance of getting the boat back to that point (where you lost connection).

 

[Meta4]

Also I have seen more crashed drones from people not paying attention to the fact their drone was not facing the way the display showed that it was and they did not fix (calibrate) before take off. Am I getting confused with the terminology?

If the compass is warning you that you are close to some steel, (compass error), calibrating is not going to fix that problem.
But moving away from what it's warning you about will.

 

[RTKD]

RTH is also where it will go if you lose connection.

My distrust of RTH, especially when "home" is a floating object, has led me to turning this feature off as well. When mine looses signal it's supposed to hover and wait for me to come after it. Also not a great option I'll admit, but I've never let it happen.

 

[Meta4]

My distrust of RTH, especially when "home" is a floating object, has led me to turning this feature off as well. When mine looses signal it's supposed to hover and wait for me to come after it. Also not a great option I'll admit, but I've never let it happen.

Although you don't want to have your drone returning and landing on a boat, RTH is extremely reliable.
Do you have a particular reason for not trusting it?