Commercial Trial - Lessons Learned

I went out with the local council for a demo trial today. The brief was to scout for a mooring site in a marine reserve for the public to use instead of dropping anchors.

here are my conclusions…
1 - The rov performed well in 30m of water but still i find the tether twist affecting its stable horizon at times. For me, the importance of moving tether to center rear of the rov instead of coming off one side, to reduce tether influence.
2 - I need to use a tether reel to reduce twists being introduced by coiling.

3 - This is specific to small councils in NZ. They prefer video, data and analysis as a package as they do not have the resources to process the information fully, themselves. I need to use matlab or (recommendations please) and extract useful data from the dive logs. Develop a sensor array to be installed on payload skid. Another camera (low light??? or independently recording camera as backup) to complement the one on rov now. SEE No. 5 below.
4 - GPS positioning system for mapping and survey. Comment was, that GPS is needed for accurate data gathering. Visual survey of bottom by compass bearing is a skill, i believe, that takes hours to get good at. There is no way of knowing if you have covered the same distance as the last track done. Boat drift and current complicate survey immensely. Anchor use can be an issue over significant benthic sites.
5 - Check the damn position of mouse pointer on laptop screen. I obviously bumped the touchpad during dive and because the mouse pointer was still over the record button, it turned off. No WORDS describe the pain of losing an hour of video that you would have given to client. The record button in QGC, would be better if it changed color and blinked while recording so a quick glance would confirm recording. Or auto record when rov is armed.
6 - Take the hit and learn the hard lessons so i can move forward, even though my credibility just got sucked into a black hole in a small local market.

My confidence in the BR2 development is still strong. It was considered a potentially capable tool and impressed even though i spiraled around the black hole.

Bottom line, give the client what they need by developing robust systems for operation so i don’t find myself in this position again.

These are my observations from my experiences. Make what you want from this…

What video/data integration are you seeking? What info was the council looking for?


Thanks for posting this. It’s incredibly useful to hear what challenges you’re having and hopefully we can make the ROV more capable in some of these areas. Here are my comments:

  1. On the tether affecting the horizon, it can definitely happen, especially in strong currents. However, I often find that I assume the bottom is flat but it’s not and that can be disorienting. I assume the artificial horizon was showing that you’re tilted as well?

  2. This is a great point. ROVs produce a lot of data and it’s most valuable if it’s easy to present in a usable format. The data can be extracted from the MAVLink logs - @jwalser may be able to help more with that. As far as collecting data in the most usable format, we’ve got a few things on our to-do list:

  • Snapshots with a button click to record important moments
  • Text overlay on the recorded video to note location and depth
  1. The Underwater GPS system makes a huge difference during survey work. Working off the compass alone is very difficult.

  2. A flashing record button would be a good idea. Bummer that you lost the video during this time!

  3. Thanks for sharing what you’ve learned!


Hey Kaos, I have got a AV120 Cable Reel that I got off trademe, I have got 100m of BR tether on it and a slip ring that I bought off Ebay - it works good although I would recommend getting the next cable reel up if you have 100m of tether or more.