Long-distance inspection ROV

[willson (sandy)]

Hi everyone!

I have a situation. We want to make an ROV with a 5 km tether. We have a tunnel inspection project.

According to our research, ROVs which are capable of doing this kind of mission have bigger thrusters such as Saab Seaeye Falcon thruster with 50 kgf total thrust and 14 mm cable. Can we use T200 on the ROV for this project with this long tether?

We thought if we increase the number of thrusters such as 12, we can manage the tether. What do you suggest about this and design of thrusters? Do we have to use bigger thrusters?

We want to use same electronic system with BlueROV2. We will use multi-battery system.

There are troubles about energy source of ROV. Can we run this ROV with battery or must we send the energy from land with tether? We want to use single mode fiber optic tether. Can we get all information from ROV with single mode fiber optic, such as sonars, usbl, camera, commands.

Thanks a lot!

[Tangaroa (Paul)]

Hi,
If you check this link out

5.5 hour, 2,400ft pipe inspection with modified BR2

I performed an inspection of a 2,400ft long, 24" diameter treated sewer outfall with a modified BR2. I used two 50cm 3" cast acrylic tubes as the chassis to mount the electronics enclosure and thrusters. The two tubes were secured together by attaching the enclosure clamps to each other. I also mounted the thrusters,lights, electronics enclosure and buoyancy to the enclosure clamps. [MBM-150-] I wanted to have plenty of battery capacity to haul the fiber optic tether, and to have plenty of…

The guys at seaview did a long 2.4 km inspection
They also have a battery manager which allows the use of multiple battery’s.
If you go down the road of topside power. You will have to step the voltage up a lot for that length of tether or use bigger conductors which then leads to a larger tether and more drag. So more thruster Force is needed and so on.
Everything you have listed will work over fiber optics with the exception of the USBL which won’t work in a tunnel at that length anyway as there’s too much reflection from the tunnel.
I would say you would be better off with a cable counter on your tether so you know exactly how far down the tunnel you are.

[etienne (Etienne Demers)]

Hello Sandy,

We sell a lot of fiber systems with long tethers for this exact purpose.

You can also change the thruster position to this

And double up on the aft thrusters to give you more pull. We can custom make a frame to suit your purpose.

We also sell a cable counter so you can provide positioning inside the tunnel.

Cable counter – Delta ROV Inc

The cable counter comes with a free software:

and free string configurator

The software can send a string to a udp port which can be received by our overlay software: http://www.deltarov.com/new/product/oceanvault-recorder/

Cheers,
Etienne