16/02/2024
I learned a lot a couple of weekends ago during my first time operating a drone from a small boat. I’ve just been reminded of the experience (not entirely a happy one) by sitting down to edit together the drone footage together with my A camera’s shots.
To set the scene: a small team gathered to conduct a sonar survey of a Norfolk broad, in the search for a missing, presumed sunk, wartime aircraft. A boat owner/driver with local knowledge; two guys from the company that makes and operates state-of-the-art marine survey sonar equipment, and me with my camera gear, climb into a perhaps 15-foot aluminium skiff. To the side of the skiff is tied the high-powered sonar transducer, dipping into the water. In the boat with us is a petrol generator to power the sonar, a box of electronics, a precision GPS antenna, a snakepit of cables and a rugged laptop controlling it all, my FS7 doc camera, with radio mics on two of the crew and a top mic, and my old but powerful (and I won’t cry if I lose it) DJI Mavic Pro.
We’d decided against bringing a second boat, because it would take up a lot of time and effort to fetch it from its usual home on the coast, check it over and prepare its motors and launch it, and then to recover it and take it all back again. The little skiff we had was okay for four of us – as long as we were content to sit still and not move around.
This is okay up to a point, but it means all your shots will look very similar and be hard to edit, because you can’t move to get a different angle. It also means that after an hour or so, you’re dying to stand up and stretch. The next problem is that you’re sat next to a really noisy two-stroke outboard engine, which of course is running all the time, and besides that, there’s a petrol generator running at the other end of the boat too. Not a recipe for pleasing sound or footage.
Still, at least I’d be able to spice it up with some drone footage, right? For the first hour or so, there was a brisk, blustery wind, and it really didn’t seem like a good idea. A couple of hours in, I’d pretty much exhausted every conceivable shot from my fixed position, and with the wind having eased somewhat, I was prepared to give it a go.
First problem: insufficient space to launch the drone from the boat – and in any case, it was likely to complain about being asked to set off from a sheet of metal. Fortunately, the boat driver was happy to hand-launch for me and did so with total aplomb (I suspect he’s done this before), agreeing also to hold the boat still in the water for me to recover it in ten minutes or so.
And all went well for a bit. But then our plan with the boat was to make repeated passes across a lake, covering a large area of it systematically in about ten-metre swathes, and of course to do that, we turned 180 degrees and reversed course every so often. I, concentrating on the shot I was getting for a bit, and looking down at my shaded screen, wasn’t paying attention to the rotation of the world around me as we turned, and I quickly lost my bearings and lost sight of the drone, and the drone lost sight of the boat.
I picked up the drone in the sky again very quickly – I hadn’t been looking away for long (visual line of sight and all that) – but picking up the boat againnin the drone’s shot proved difficult – the boat was moving, and I’d no sooner got it back in frame than it made another about turn and disappeared again…
…and so the long day wore on. Or so it felt! I quickly realised that I was going to have to work quickly and hard to get the boat and the drone in the same part of the broad at the same time before the ten minutes or so of flight time was up. Return To Home won’t work when “Home” is a boat that isn’t there any more!
I abandoned much hope of getting decent shots in favour of simply flying the aircraft to where we would intercept it at a turn and could recover it. The wind of course had got up considerably by now, so the drone flew rather faster in one direction than in any other, making it difficult to judge. The combination of the wind and current acting on the boat made it hard for our helmsman to hold it stationary, so I really had to try to fly the drone on a course intercepting the boat’s course at a shallow angle, holding it close to the boat’s speed to allow our helmsman to reach out and grab it from underneath, which he did very adroitly, to my enormous relief.
Lessons learned:
• use a separate boat for camera and drone work if at all possible – it’ll be well worth the effort. Also, it’s MUCH easier to launch and recover a drone from a stationary boat; if your work boat has to keep moving to do its work, that’s another reason to use a separate boat as a filming and drone platform.
• You’re going to need a spotter/catcher if you’re using a small boat that’ll turn or change its position in the water – it’s terribly easy to lose your bearings when your attention is on the screen. When you look up again, the world may have rotated around your boat (yes, it’s the boat that rotates, but it doesn’t feel that way to you), so that you have no idea which way is which, which direction to look in to see your aircraft, or which way it’s pointing when you do see it. A spotter can help with all of that. I was lucky that our helmsman was happy to multi-task and be catcher as well as operating the boat, but catching a medium or large drone isn’t for the faint-hearted or inexperienced; it would have been better to have someone with me I knew I could count on.
• An better alternative may often be to fly the drone from nearby land. That wasn’t an option in this case; I knew from earlier recces that the nearest land was only accessible by walking for an hour or so, and that you couldn’t get line of sight visibility from there to the open broad because of a large, tall reedbed in the way. Working from the workboat or a second boat was the only option.
I had anticipated some of these problems, but by no means all of them. I’m writing this partly as a lessons-learned note for myself, but also in the hope that it helps someone else. I got my aircraft back – and got a couple of minutes of usable footage – but without some prior skill and experience flying, and some luck – I might not have.
