First of all, my intention is not to accuse bluerobotics but today we had major S*IT/FIRE at our working site and still not sure is this our mistake.
For few weeks we are working on inspection of sewer outfalls and making same daily routine:
Check/vacuum test
Make asset inspection (mission)
After mission clean in fresh water / dry
Check again
Everything worked fine until today.
2 minutes after dive (depth 1,5 m) we had picture lost for a second and sudden voltage drop on full battery. Immediately we started dive out and found out that 4" enclosure is full of smoke. Quickly unscrewed battery vent and unplugged battery. After opening 4" enclosure smoke and salt water came out.
At first I thought that yesterday we didn’t properly closed vent after pressure test.
When we came back to office we preformed new pressure test (Still at that moment I was sure that leakage is caused by not properly closed vent plug). Immediately we heard air at dome end cap and when we looked more closely to see cracks around the dome. We found leaking spot at position 8 on the picture bellow.
We were surprised by the number of cracks around the dome so at that moment we thought that maybe we hit something with bluerov2 while there was no image transition.
Luckily today we preformed inspection with add on cameras so we check footage and found out that we didn’t hit anything. NOTICE: Have to say that we have special car/vehicle for transporting Bluerov2 so surely we didn’t damage it in transport and are always cautious when handling Bluerov2.
Later we found this topic CLICK TO LINK with same problem so this can be production error.
Considering all of this we are warning BlueROV community to check their ROV so they can prevent damage. Now we have to buy new BlueROV2 Enclosure for $1.200 and new thruster (if we are lucky just one).
How old is your BR2 as Blue Robotics has redesigned the 4 inch dome to improve its structural integrity?
Also, since you are doing sewer inspection, could the acrylic dome have been subjected to a contaminate in the sewage that caused some kind of damage/stress at the bend in the dome where the cracks occurred? Just a thought.
That doesn’t look right at all, I’m sorry you’ve had this issue occur!
Yes, that is an older 4" dome, the R2 version specifically. As described in our blog post here, we switched to the R3 design with separate a dome and retaining ring on April 24th.
The R1 and R2 designs were laser welded together rather than two separate pieces. If the dome screws were overtightened, the uneven pressure could cause stress in the dome. Over time, this could occasionally lead to cracking in some domes. We have only seen the R2 domes crack very rarely, generally during transportation, and have never experienced it ourselves. The R3 domes cannot have this uneven pressure occur, and are less expensive and more robust as result of the simplified manufacturing process.
Have the screws been removed from the dome and flange and replaced, or have the screws been tightened more than they were originally? Or have the dome screws been untouched since production?
This is probably a good reminder for those of us with the earlier domes to consider replacing them. BTW Adam is the clear dome available as a spare part just by itself (without the retaining ring)? (our domes tend to get fairly beaten up on a regular basis )
Just like any equipment going into the water, its always a good idea to inspect before every dive to make sure everything is in order and there is no damage.
The dome itself without the retaining ring isn’t currently available on its own, but we’ll we’ll into making that happen!
We have a complete pre-dive checklist and the recommended maintenance available in the BlueROV2 documentation here. The dome is not considered a wear part beyond cosmetic scratches, and it should not normally be necessary to replace. The failure you have experienced in an exception, and by no means the rule.
since we @vectrino-hr previously had dome problem I am bumping this topic again with some questions.
In the end of this first dome end cap problem, we replaced broken dome cap with new updated one (R3), and had no problems prior to yesterday’s inspection.
Yesterday, during our usual check up before diving, we found out that our retaining ring broke:
It is broken at hole that is used to hold front end of 4" enclosure in place, so I would like to state that we are always careful not to overtighten it. Also, later upon further inspection, we saw that also, dome broke on one place, cannot say in which orientation that part of the dome was:
So, does this happen often? Is it something that we, and everybody else, should be aware of?
Is it safe to use it “cracked” like this, both dome and retaining ring?
Like I said, we really are careful when tightening two screws that fix the dome to aluminium bracket, because we were aware that this may happen, and still it happened. Luckily, it did not cause anyfurther problems like our previous dome crack.
Again, like the last time, please product support to respond to this issue.
I can’t say this is something we’ve seen happen often with these retaining rings. And it would take quite a bit of force to over tighten the screws enough to crack the ring. Please contact us at support@bluerobotics.com with your order number and we can help you from there.
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