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Configuration / lessons learned from deep dives?


(undersearobotics.com) #1

I watched the latest videos posted by @rjehangir of their dives to 1050 feet in the Santa Barbara channel. How did this BlueROV2 configuration differ from the standard kit? What lessons were learned from such a deep dive?


Filming deep soft bottom Corals Sweden
(Rusty) #2

Hi Paul,

This BlueROV2 was the standard configuration except with the upgraded aluminum tubes for the 4" and 3" Series enclosure.

I do have to note that we had a very minor leak during the deepest test at 340m. Over the span of 15-20 minutes, about 10-15 drops of water got into the main electronics enclosure. We think that happened through the tether penetrator, but we have not verified that yet. I think we can come up with a solution pretty easily, but I wouldn’t recommend going to this depth quite yet! This was our first test at the depth and almost 3 times further than we had ever gone before!

Another lesson - the tow sled that the ROV was tethered to made this dive easy. Without that, it would have been very difficult. Dragging around 300m of tether behind the ROV just wouldn’t be possible.

-Rusty


(undersearobotics.com) #3

That’s amazing performance from a low cost ROV!!!

Was the ROV powered by internal batteries or power from the tow sled camera?


(Rusty) #4

Thanks, Paul!

It was powered by the internal batteries.

-Rusty


(undersearobotics.com) #5

Using the stock battery? How long was the ROV underwater all together? It usually takes a while to dive to that depth…


(Rusty) #6

Paul,

Yes, the stock battery. We actually just got pulled down and up by the tow sled, which is on a winch, so we had tons of battery life. The first dive was around 1.5-2 hrs and we had plenty left when we came back up.

-Rusty


(undersearobotics.com) #7

Right, that’s one of the advantages of using a TMS, or in this case, a towed camera.

This is truly impressive and clearly shows the huge advantage that an “open frame” thruster has over conventional fluid filled thrusters. I’m equally impressed that the housings, and in particular the epoxy filled penetrators, held to that depth.

Well done!


(Kevin) #8

I concur, excellent work guys! It was fun watching the videos. This is pretty much how the E/V Nautilus does their ROV operations as well.

@paul-unterweiser We’ve been out and tried just free tether dives out to 100m before and they just don’t work well. The boat gets dragged by current and wind much quicker than the ROV, so staying in any sort of a position is just difficult and not recommended.

This TMS method with a sled is definitely cool, but will require some heavy machinery and a winch, luckily, I have an A-Frame starting to be made up for my boat :slight_smile:


(undersearobotics.com) #9

The machinery may not need to be that heavy depending how heavy the TMS cage and wire is. FYI using a separate towed unit with an ROV is nothing new. I’m not sure who was first but my first experience with a system like that was while working with WHOI and Jason / Medea in 2002.


(Tim Pierce) #10

The camera dome took 1000 feet? Impressive! Maybe my treasure wreck target is reachable then!


(Rusty) #11

@Tim - yes, the dome is pretty awesome. You should be pretty safe going to 1000 ft. We’re still trying to figure out the actual maximum depth but so far we’ve seen slight damage at 500m and failure at 700-900m.

-Rusty


(Tim Pierce) #12

Very cool!

Do you have any pictures of the tower sled? Is it a ROV garage? Are you able to feed and retract tether from it?


(Nikos Maurommatis) #13

Can you post more details about the sled? It sounds a very interested project!!!


(Bryan) #14

Awesome.

I have had good luck using ShamWow material to absorb stray drops. I use the stuff in rebreathers to absorb extra moisture near the CO2 scrubber.

Bryan


(Rusty) #15

@nmau - You can find out a lot more about the sled here: Towed Camera Sled


(Nikos Maurommatis) #16

Thank you, Rusty! I will study it carefully…