Hey people,
I’m planning ahead and trying to think of ways we might be able to measure the distance along that the ROV is in a certain area. For example, if we are doing inspections and have 100m of tether, how would one determine how far from the start point you are when you find a defect or something else that needs investigating further?
If anyone has found a way that works well to do this I would greatly appreciate a heads up on how you do it.
Thanks in advance 
Julie
Waterlinked UW positioning and then handling position and plotting in OpenCPN
The easiest way is by noting the distance that is printed on the tether at the point closest to the vehicle, subtracting that from the distance at the surface, or the entrance to the tunnel.
For pipe and tunnel inspections, I run the tether through a line counter that outputs an ascii string of feet, meters and station. I send the data to the video overlay as well as the profiling sonar software.
Awesome, we are still in the business case phase of getting our company to agree to purchase and didn’t realise that the tether could have the distance printed on it so that is really good to know!
The line counter sounds like a great solution to then overlay the data to the video. That would be exactly what we need to do I would think for the pipe inspections we are looking at it for. Thanks 
Thanks Bo, I was looking into the Waterlinked UW positioning but because we would mostly be launching from land or a dock, I wasn’t sure it will work for what we are doing. Would be a potential for some of the work we would do for sure, just not all of it I don’t think?
