Exploring bottom structure 300-500m depth


#1

We fish offshore in the Gulf of Mexico at depths up to 500m trying to locate bottom structure composition but it looks like 100m depth seems to be where the technology is currently at for DIY or the average non-commercial consumer (though I did see a post on here where someone took the OpenROV battery capsule down to 200m and was going to test at 300m).

  1. Where is a good resource to research commercial or high-end consumer/DIY models that includes pricing? I’m wagering most are out of our price range but would like to know what is out there for the various depths and prices.

  2. Is 300m the technological max for a tether for OpenROV meaning the signal breaks down after that?

  3. Is there any way to triangulate the ROV’s position underwater relative to the boat in order to get a semi-accurate GPS reading of the ROV? With neutral bouyancy I imagine we have to drive down to the bottom rather than dropping like a weight so we’re likely to get more off track from the currents.

  4. Is visibility at these depths mostly up to the current sea conditions and bottom composition as to whether the video is viewable (assuming we use the external light cube)?

Thanks!


#2

Hi @gregorio.brown, welcome to the forum! Yes, you are correct, 100m is out limit right now, although there are advances going towards 300m. Give the community about a year and we’ll probably be at that depth. Also keep in mind that there is a significant cost increase in the vehicle as you go deeper, do to the machining and exotic materials that have to be used to withstand that depth.

Unfortunately, there isn’t a single resource that lists all the Observation Class (OC) ROV’s and their prices. You almost always have to ask for a quote to see the price.

If you have a requirement to get to 500m, the only OCROV I can think of that can get that deep is the Seabotix vLBV 950. The VideoRay Pro 4 is limited to 305m and the Outland 1000/2000 are limited to 300m. You’re looking at about $60,000 base for any of those systems. DeepTrekker has a good page about most of the more affordable ROV options.

There are systems for underwater positioning, but they are quite expensive. Tritech’s MicronNav ($19,000) is the most common, but there are other manufacturers such as Applied Acoustics. I had a quote from them a few years ago for an Alpha system that could plug into a laptop for about $15,000.

A member by the name of @Jim_Trezzo is working on a lower cost acoustic positioning system: Acoustic Location System

Yes, visibility is entirely up to the sea conditions and bottom composition. If you have a storm blow through with heavy surge, it kicks up a lot of the silt and plant matter. You will need to wait a few days for calm weather for the bottom to settle out.


#3

Thanks for the response, @Kevin_K!


#4

Hi Gregorio:

With regards to question 2, we don’t know yet what the maximum range is for the Homeplug AV adapters that we’re using on OpenROV. So far the longest tether we’ve used is about 320m and they seemed to be working fine. Right now I have an experimental deep ROV set up with a 420m long tether, and we’ll likely be taking it to Lake Tahoe later this month to run a number of tests on it.

If tests with a 420m tether are successful, we will keep lengthening the tether until we find out where the protocol breaks down.

-W