ROVL Dive Log: Unknown Aircraft Wreck

I’ve been fiddling with my ROVL MKII for the past few months and after figuring out some compass things between both my ROV and ROVL, I managed to get on my first new target in years.

It appears to be an old radial engine aircraft that hit the water hard enough to cause a pretty large debris field. The engine block was easy to spot, but there are other pieces scattered around requiring further exploration.

The ROVL provided an effective means of quickly getting on site without the need for a marker buoy. The stop halfway was me holding position a bit in the higher than average current to get down to the bottom.

Some tips that I think aided in my success:

  1. Rigidly mounting my Receiver to the boat using RAM mounts. I have it going into a fishing rod holder so it can be removed.
  2. Doing my homework for speed of sound calculations and magnetic declination.
  3. Making sure the compass heading and movement matches plotted direction of movement. I originally had a mismatch, so I adjusted some setting in ArduSub.

I have plenty of multibeam echo sounder targets in my area, so it looks like I might be able to get out to two a day with the ROVL speeding up what had previously been a positioning problem.

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Awesome update Kevin,
Funny you mentioned compass declination. Where I am the declination is significant (-17 degrees). I’ve been trying to get the various compasses to agree with each other too.

Question: Did you set your location’s declination in the ROVL as well as ArduSub? I also have the DVL-75, and wondering if that too should be set with the declination value.

Good luck with the other targets you have!

Hi Ken,

Yeah the compass issue was an interesting one to tackle! I’ll mention what I did here, but your mileage may vary and none of this is confirmed by the BR software team.

ROVL: Entered 11.31 for declination. This is the reading for my area in Southern California. I used this calculator: NCEI Geomagnetic Calculators


With the COMPASS_LEARN enabled, the compass will slowly adjust itself to True North (and continue to update itself) so using the COMPASS_DEC parameter isn’t required.

I don’t have a DVL-75, so I haven’t been able to throw that into the mix yet to firm up the position estimation. From looking through the CeruleanTracker software, I would probably recommend manually setting that to the same value as your ROVL.

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