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900m Permanently Submerged BlueROV2

Hi Everyone,
I just wanted to announce our project using a BlueROV2 Heavy that has been customized to withstand “permanent” placement at 900m deep. We plan on keeping the equipment on the seafloor as long as it continues to function. We worked together with Blue Robotics on this project and I am happy to report that the ROV has been submerged at 900m for 51 days now without any issues. Additionally, the system we created allows us to tel-operate this ROV from anywhere in the world assuming a decent internet connection. The ROV is located at the bottom the of the Monterey Bay off the coast of California connected to the Monterey Bay Aquarium Research Institute’s (MBARI) cabled observatory called the Monterey Accelerated Research System (MARS) (Monterey Accelerated Research System (MARS) - MBARI). We have constructed our own student educational platform that consists of a few student activities including the ROV, a separate PTZ camera, and a hydrophone. So far, the ROV has been tel-operated from as far away as Okinawa Japan, and has even been flown over a Starlink satellite connection from Canada. Users in western USA are getting pings of around 30ms average and we have even seen pings as low as 17ms average.

The main customizations we made to the vehicle include:

-Subconn connectors for all penetrations
-Slightly thicker aluminum housings
-Slightly thicker acrylic dome
-Syntactic foam buoyancy with additional foam to support added weight of connectors
-Zinc anodes
-Custom hybrid power system for charging ROV over tether.
-Falmat neutrally buoyant tether

Other than that, the ROV is pretty much in stock configuration. We did not change much to the main housing electronics and the lights are stock Blue Robotics Lumens.

The goal of this project is to inspire young students by allowing access to equipment and environments that were previously inaccessible. The Quest Institute already has programs that allow students to send experiments to the space station, and now we have the ability to allow students to operate equipment at the bottom of the ocean.

Check out some of the cool marine life we have seen by visiting our YouTube channel here:

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Very impressive. Congratulations!

This is extremely cool! Are there software limits or anything to keep the ROV safe while it is being teleoperated? As in to prevent stress on the tether

Hi Stephen, this is very impressive! I work with a educational marine science program in northern California, on the coast, and would like to learn more about the Ocean Discovery program and if it would be accessible to us. Thanks

Currently no. As far as I know there are not any options for this via software. In the future we would like to include some additional HW to help protect the equipment like a DVL. I should have mentioned that the tether has also been changed to a Falmat ROV tether with conductors that are a bit higher gauge compared to the FathomX tether. We do have strain relief at both ends of the tether and tether itself has a strength of several hundreds pounds.

@hube268, awesome writeup and thanks for sharing.

I was lucky enough to fly this ROV a few weeks ago and it was quite amazing to be flying an ROV from hundreds of miles away, especially one at 900m depth! I was particularly impressed with the latency, which was no more than if the ROV was connected directly to my computer.

Amazing work!

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Wow! It’s very, very fascinating. A very marvelous work of marine ROV engineering. How does this augmented BlueROV2 receive it’s power?

This is so awesome, Stephen!! We would love to share the success with our social media community if you don’t mind? Thank you!

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Sure @kristelhall! I just sent you an email response.

Hi @CBW3750, The ROV is battery powered but the battery is charged over the tether. The ROV tether is connected to our subsea platform that includes a couple of other activities and also has all our systems for power and control. Our platform is then connected to the MBARI MARS cabled observatory which is itself connected all the way back to shore by a 30-something mile long subsea tether. The MBARI link I posted in the original message is to the MARS page which gives a lot more information about the node if you are interested.

Hi @crans I sent you a private message. Look forward to hearing from you.

Really impressive, looks like a super interesting project! Thanks for sharing the details.

@hube268 Can you share the details on the upgraded housing tubes and acrylic dome? I would like to modify my BlueROV2 to go down to around 1,700’.

Hi @btrue. The upgraded enclosures were provided by BlueRobotics. The 6" enclosure is similar to their retail aluminum enclosure but they added a rib in the center at the same thickness as the ends which essentially makes as strong as if the enclosure was half the length. The 3" battery enclosure also done this way. The Deepsea Power and Light program “Under Pressure” is an easy to use software that can help you determine the material and thickness needed for that depth. Link to the SW: Under Pressure Design Tool for Pressure Vessels and Enclosures
I believe the Blue Robotics enclosures may be able to handle 1,700’ which is about 518m.

For the dome, that was a prototype dome that BlueRobotics provided to me for this project. It is thicker and I had to create a special bracket to secure it to the flange. I’m not sure what depth their retail domes are rated for.

Thanks. For reference, The stock aluminum tubes in the store are rated for 400m (1,312 ft), and the dome is rated for 500m (1640 ft). It looks like the regular dome will work for me and I can make my own enclosure tubes on a lathe if I needed to. I was just wondering if you bought the tubes off the shelf somewhere.

@Stephen Impressive and fascinating deployment. Congratulations and I wish you a lot and longlasting fun with it! :wink:

Would you mind sharing some thoughts about how you selected and installed sacrificial anodes onto the aluminium enclosures?

Also how long is the tether and how do you manage the tether? Do you somehow pay it out / in to avoid entanglement or isn’t that an issue at all?

Hi @hube268 congratulations on this amazing project! We found it very impressive and we are looking forward to hear more from it.

I have a quick question, are you using the temperature sensor Celsius Fast-Response? if so, how has it behave on long term measurements?

Thanks!

Hi @aib, There isn’t a lot of room on the ROV so the zinc annodes are smaller pieces bolted to the frame with wires running to the various enclosures including the 6", 3.5" and even the lumen lights. These are all connected to the enclosures using terminal rings connected to a screw on the endcaps of each enclosure.

The tether is 40m long. We don’t have a system to manage the tether. We looked into making a winch to reel the tether back in but there was just so many additional potential failure points that we decided to just do the simple solution. The way we avoid tangling the tether is to just practice good ROV flying practices and parking the ROV on the seafloor at the end of the tether when we are not flying. We used to park the ROV in the garage we created on our platform but we found that the current would bunch of the tether when we were not using it and we would need to spend a lot of time untangling it. Since we have started parking at the extent of the tether we have not had any issues.

hi Sergio @DeepCoTech, We currently do not have a temp sensor on this ROV. We had one on the previous deployment and the readings were consistently at about 1C. We removed it on this deployment because the potting coating failed and was causing a ground fault. Given that issue, we decided to leave it off of this deployment to increase durability of the system. That being said, I think the main problem was that the ROV was stored between deployments and the potting dried out so if we had replaced it, the sensor probably would have been fine.

Hi Stephen, thanks for your answer