It’s tough to find affordable Cat5 cable that is suitable for use as a tether, unfortunately. None that we’ve found a truly suitable. You need something with stranded wires, light weight, ruggedness, and strong construction.
We’ve been working on a solution to address this for months now and we’re getting very close to releasing something. We’re currently on schedule to launch the product in the second half of April (2016). I won’t say too much about it now but it is a very high quality cable that ideally suited for use with ROVs. In addition to the cable, we will have several tether interface board options to provide lots of flexibility and capability.
Tom C is one of our beta testers for the cable and posted more detail here.
I know it’s taken a long time, but I think everyone will be very happy with the product! We’re certainly looking forward to it.