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Tricky leaking BR2

Hello guys,

I’m experiencing a very tricky leaking which I cannot address. I have a BR2 with aluminum enclosures, while we test it for 15 minutes at 26 Bar the pressure maintain perfectly is doesn´t move at all but when we had a dive it started leaking at 55 meters depth… we were very surprised fortunately the water did not affect the electronics (around 2 cm inside the 4 aluminum enclosure).

Once we removed water from the ROV we did the leak test again with positive results… the enclosure is not leaking at all. Once again we have sumbmerged but this time up to 20 meters for 10 minutes just to check again we found water in the ROV this time an small amount due that we submerged it only up to 20 meters.

So far we have checked:

  • penetrators oring: all in place
  • radial Orings: all in place
  • Any cut on the cables from thrusters or lumen lights. nothing at all
  • replaced vacuum plug
  • Run the test with different vacuum pump. Same result

Any ideas how to proceed with anything else? Just want to point out the very first time we had water inside our bar30 was not responding and suddenly it came back to normal again. Is there a possibility that the bar 30 might be leaking?


I had some problems that turned out to be my vacuum pump, but contacted support and they advised using a small amount of pressure and dunking it to look for bubbles. I don’t recall how many psi, but it was low, maybe only a few pounds and you should work your way up.

I had a small leak from the temperature probe a while back. I used the method @corndog used. A small amount of positive pressure through the vacuum port in a tank of water. Sure enough bubbles! Replaced the temp probe, all good.

Thanks @corndog and @k-deboer we are proceeding that way!

It would be great if the vacuum pump model was changed out to one that can also give positive pressure…

All of my difficult to find leaks have ended up being
1/ Leaks down the wires themselves (hosing its called).
The main power cable from the battery to the main housing looks tough but has an extremely thin rubber jacket in places. I have had to remake this cable several times because of leaks.
The light cable is also very thin and vulnerable and has no water blocking. Several of mine have leaked. The lights fail with this one so easy to find.
2/ Penetrators can leak. Earlier penetrators used an epoxy that didn’t always bond perfectly between the cable and the inside of the aluminium penetrator bolt. I have had several failed bonds and leaking penetrators. The thicksotropic resin used now is much better.

The best way to find these leaks is to hang the rov by the front of the rov and attach heavy weight to the rear of the rov. Lower the rov into the water so it hangs nose up. Submerge it for a while then lift it keeping it nose up. Dry the outside and carefully open the main housing from the rear while keeping everything nose up. Inspect every penetrator on the inside and you will see droplets of water on the failed penetrators where the wires exit the penetrator. Hope this helps.
When finding any leak it is helpful to use gravity to help find your leak. Submerge it vertically one way and check for water droplets running down the inside, then do the other way. That’s what I’ve found anyway. Cheers