So just wanted to share a couple of observations we have made with the BROV after a 60 day 12 hr per day deployment. I want to say that the machine performed well and we were pleased overall. Here are the takeaways l
The lumen light cables are not water blocked and when the jacket gets nicked it lets water flood the lights one by one even with the wetlink penetrators.
The Wet Link connector between the battery bottle and the electronics housing will fail from the repeated use changing batteries 4-5 times / day. The area that is compressed in the connector seems to leak after awhile.
We were working in fairly cold water, 3c, and air temp was about 25c. Over time we started to get hairline fractures in the camera dome. We believe this is from the rapid thermal cycling. The fix was to change the dome every two weeks.
Another point of failure was the connection point on the frame at the bottom between the vertical sides and the bottom. The material between the square nuts and the side plate fractures allowing the nut to pull out
I’m interested in knowing which version of the BlueROV2 you’re working with. Is it the latest R4 (with Navigator flight controller) or an older version (with Pixhawk)?
One was a v4 the other was a v3 that ended up with v4 parts in it. Both had navigator boards, A50 dvl’s and tritech 1250idk’s. In addition we supplement the onboard camera with an Orphie cam.
For the inspection work we built a skid with a Voyis discovery cam strobes and a fiber tether.
Capillary action is very effective at wicking water through gaps (especially when combined with high water pressure). Our WetLink penetrators are designed to seal against the smooth face of a cable jacket, preventing water ingress where the cable enters an enclosure, but you’re correct that internal leaks / water transmission through a cable are not prevented without a water-blocked cable or connector.
Our only water-blocked cable is our tether, but even there if a cut is bad enough to nick the insulation of one of the wires (instead of “just” tearing the cable jacket) it’s still possible for there to be water ingress along the wire strands (although at that point there are also inevitable issues with corrosion of the wire).
All our cables are manufactured with jackets that are resistant to chemicals and abrasion, but every design has trade-offs, and for cables that’s typically against strength, flexibility, weight, and cost. I’m curious whether your application involves sharp objects and large forces against the cables, and whether the mounting of the cables seems to expose them to more risk than is readily manageable with vehicle control?
Was this an actual connector, or a penetrator? We have been designing and testing different variations of WetLink connectors for years, but they are not yet finalised or publicly released, so if you’re actually testing them then that feedback is best passed directly to our R&D engineering team, so it can be factored into the final product
Was this solely with our older acrylic domes, or also the hardened polycarbonate domes we recently released? That’s helpful to establish whether this is mostly useful information for existing users, or something we should factor into the specifications for the product we’re currently selling
Do you know whether this was on both your vehicles, or just the v3 one?
Part of the v4 revision was some frame design updates to improve the strength of the slot nut pockets, so it’s good to know whether that’s working as expected or sometimes failing when subjected to impacts and/or repeated thermal cycles.
Once again - thanks for the feedback and your insights! It’s great to have discussions on what’s working well, and what could be improved
We are in the Utility / marine construction market. This particular job we were working on a burried trash rack with 1ATM suit divers and a dredge. Our part was inspection so we weren’t really touching anything on a regular basis, but when working with divers even this is kinda rough. As a side note, one indicator of a leaking light is intermittent connection drops in cockpit. We did install cobalt connectors on the electronics bottle to water block it.
As for the wet link connector on the battery housing the repeated openings for battery swaps seem to wiggle the wires so much that there gets to be play in the rubber of the connector. It will begin to weep slowly so there is ample warning as to when it needs to be changed. We usually just cut the insulation back 10mm and reseated it
I’m not really sure on the dome material, they had been around for a bit so possibly they were the older ones. We did have one brand new one develop a crack on the flange after the first dive after changing it, I’m guessing it was installed cracked or cracked during installation.
The v4 frame is a,ot more rugged, so yes that makes a difference. Our launch was out and over a containment boom about 2m off the barge so it was a big toss from 2.5m up 5x a day. Recovery was bounce it over the boom and 50% of the time smack it on the side of the barge.
Hi @ktweed -
Thanks for all the feedback!
Are all connections swapped to Blue Trails Cobalt connectors?
If you’re referring to the WetLink Penetrator glands on the battery housing, it’s worth noting the rubber seal that is compressed to form a seal against the cable is not typically reusable! So strippingn back the insulation and re-compressing it is not expected to produce a seal. Swapping in a fresh seal, and tightening the plug until it is up against its endstop will make the connection waterproof to 1000m, permanently. If this proves not to be the case, I would suspect extreme thermal cycling is affecting the elastomer the plug is made from…
Tightening the dome bolts in a star pattern is important - if this is not done, it can definitely lead to cracks during installation! It can sometimes be important to not fully tighten the first bolt or two as you work through the star pattern, returning to them after the others are tight.
I too enjoy a good ROV toss, but it is possible to reduce the impact load by lowering the vehicle by its tether - this is usually prudent from heights more than 6 feet. Similarly, using a gaff pole to scoop up the ROV can reduce the load on the tether, and the risk of banging things around quite as much.
Finally, with such intensive use, I’m curious if you had any issues with any of the vehicles thrusters?
Getting detailed feedback like yours from folks heavily using the equipment is always super valuable to our team, thanks so much!
