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Submarine Cable

(davo) #1

Hi Rusty,
Before I get into the nuts and bolts of of what I need your assistance with, I’ll give you a BRIEF history.
We purchased a the BlueROV2 back in October and are quite pleased with it. Haven’t done a whole lot with it, a few inspections and a body recovery/searches.
I myself am a commercial diver for 30+ years and owned/operated my own business till recently as I have sold it.
NOW - in the the past we have inspected 2 buried submarine cables X 15km each using divers walking along the bottom using the FISHER CT-1 cable locator to identify any exposed cable that maybe vulnerable to anchors or fishing equipment.
Last year we installed 2 New Submarine Cables again each 15km so now we have 4 Submarine Cables to inspect.
It is getting harder to use divers with all the new regulations, so we are looking for something either autonomous or something we can fly from boat?
Depth Max. = 122’
Current Max. = 2.4kts. with about an hour of slack water .
Vis. range = 0.’ to 15’

Currently I’m trying to install cable tracker to BR2, but I don’t think it will be manageable.
We are planning on starting inspections next week using divers, but we are definitely going to look at alternate methods, SO this is where you come in.
I have reviewed the Acoustic GPS System and not sure if this is accurate enough to complete the inspections.
The 2 New Submarine Cables we have coordinates for every meter/ft., the other cables we have coordinates at various locations.
Now with all this said remember I’m a Commercial Diver and not tec savvy by no means.
If you can do some brain storming as to method or something that is available then I’m sure we can work together to make it beneficial to both parties.

Thank-you for your time Rusty and look forward to hearing from you and better yet your solution.
Diveco Holdings Ltd.
Dave Gormley

(Rusty) #2

Hi Dave,

Thanks for the post! I’m thrilled that the BlueROV2 is working well for you so far. It’d be great if you were able to use it more for these cable inspections.

The BlueROV2 should be able to handle your operating conditions and depths fine. As far as tracking the cable, there are a few options. What have you looked into so far? When you say “cable tracker”, what sort of product do you mean?

The Water Linked Underwater GPS system could be a good fit for this since you have accurate coordinates for the cable. It’s possible to set up a track in QGC that would show the coordinates on the map and allow you to follow them with the ROV.

Alternatively, it may be possible to use a sonar to track the cable and image it. We’ve worked a bit with imaging sonars like the Tritech Micron and Tritech Gemini 720im and they would probably provide sufficient data to track the cable.

Do you have any example pictures or sonar data from dives? That might be helpful to see as well. We’d be happy to help out as much as we can! I’m happy to discuss here or we can move to email at rusty@bluerobotics.com.

Let me know!


(davo) #3

Hi Rusty,
Thanks for the quick response.
Regarding the sonar; the cable are buried 3’ so the sonar wouldn’t pick up any image.
The Cable Tracker is hand held by the diver and and it picks up the current going through the cable, enabling the divers to follow the buried cable. The cable locator is supplied by JW Fisher model CT-1. Basically it is a 4" tube by 4’ and has LED readouts that allow the diver locate the buried cables.
I will send photo when I fix it to the BR2, but I’m skeptical about flying the ROV with this attached.
I guess I need more info on the GPS system as far as the tracking system.
Such as how accurate will it be, any deviation from track to correct itself from offset, basically I would need it to stay on track to record the seafloor as it is following the buried cable coordinates?
Also will an internet connection be required to run any of the software?
In theory we need an ROV that will follow from coordinate to coordinate of the cables and record information.

Be in touch,
Dave g.

(Tim Pierce) #4

Basically, that cable tracker is likely either a toner that locates a signal from a generator on the other end, or a metal detector. Since Fisher made it it’s likely a metal detector. You may run into an issue with it detecting the ROV, particularly with the motors running. If it were me, id get a long carbon fiber pole, mount yhe thingy on one end in front of the rov along the centerline, and then use counterweights and float foam to offset the mass and drag.

(davo) #5

Hi Tim,
Not to be ignorant, but I’m not sure you understand the scope of the work.
We have the cable locator and use it with divers walking on the seafloor. Been inspecting the cables for 30 years and have walked over a hundred miles on the seafloor using the locator.
We would now like to use a ROV to inspect cables.
We have in the past used working class ROV’s for repairs and the installations of new cables, but not practical for inspections.
Hope this sheds some light on the scope of work.


(Tim Pierce) #6

The point there was that depending on the type of cable locator you use, and specifically the underlying technology, it’s going to detect the ROV instead of your cable if it’s too close to the ROV. Human divers aren’t generally made of metal and the metal parts of dive helmets and whatnot are generally far enough away from a detector to not trigger something like that if it’s a metal detector. A ROV on the other hand emits massive magnetic fields when the thrusters are used. If it’s a radio pulse signal detector such as commonly used in the Telco industry, that’s a different story. I understand exactly what you are trying to do with that detector just fine thank you.

(Paramal ) #7

Hi Davo,

Have you considered useing the Inovatum Smart tracker. Is the smallest PipeTracker that we normally use on sub, for example a Seaeye Falcon. That being said it’s payload comes in at about 7 kg. Why don’t you look at using Blue Robotics heavy configuration. It will give you the extra lift you need. You will have to add additional bouyeny// floats to the sub to make it more bouyent.

Being a diver you can always test the floatation of the sub in a pool with scuba. Your other challenge would be to power the PipeTracker. The coils are quite demanding and use a lot of power. If the batter power on the sub is limited whey not run a spare power cable doubles up next to the sub’s umbilical. The spare quad in the fathom umbilical should be fine to run your telemetry up to the surface laptop. If you need information about suppliers I can put you in contact with a few guys.
Hope this info helps Mate.


(davo) #8

Hi Paddy,
Thanks for the info, the SMARTRAK is definitely a lighter payload.
I sent an email for pricing.


(Chris Geary) #9

HI @spudder, I’m applications engineer at Tritech. We’re currently working on a new split head Parametric sub-bottom profiler which might work well for this application on the BlueROV2.

basically, it is a dual frequency echosounder which looks through the sediment and silt layers at buried objects.

we are currently at the stage of testing and gathering data so it might be a good opportunity for you to try a new bit of kit and for me to get some data of the system being used in anger.

Drop me an email if you think it’s of interest to you.