Reattaching the tether after a snag


#1

I got in a pickle, and I made a snap judgement.

My tether was snagged, and even after flying back to the snag point, I couldn’t get it unstuck. I had enough free length to get it to shore, but I ended up having to cut the tether two feet from the openrov so I could recover the vehicle itself. I ended up having to leave a bit of cable in the lake, around 10m. Since I have to solder the cable back together, I want to make sure whatever I do doesn’t degrade the strength of the cable too much.

Questions:

I did learn some interesting lessons from this, so others: don’t repeat my mistake. Docks in the PNW (I’d assume else where also) have tons of old crap (fallen pilings, previous dock materials) on the bottom near them, and no matter how cool something is, don’t land on the bottom and then move forward. I’m pretty sure I was fine until the proximity to the bottom and jerking forward caused the line itself to move under an old, fallen piling and catch.

I’d also love to hear other people’s approach to following the tether back down, especially from shore. I spent almost an hour tracing my previous dive path to find the snag, only to find my attempts from above to loosen it had only made everything worse.


#2

I had a similar issue where the ROV was snagged and I had to cut the cable, but I didn’t have enough to get the ROV back to shore. Is was about 3 meters away and I had to swim out and cut the cable.

To fix it you want to go back to the instructions for attaching the tether and re-attach it again. Remove the short tail that you have and get back to the wires that emerge from the tube, where you originally soldered the tether. You need the cable to be wrapped around the long zip tie and the solder joint to have no strain at all.

I have also upgraded to the water proof connector that you highlighted. It is very strong and can certainly support the weight of the ROV. When I have wanted to be really sure of the strength I have also tied the cable through the carry handle, after the water proof connector. Then I know that I am pulling on that knot rather than on the coupling. It is probably not needed though. Someone should do a test and demonstrate that the join and connector is stronger than the cable itself.


#3

The connect mentioned say it’s IP68 which is protected from long term exposure up to a vendor noted pressure. There is no ‘spec’ on this connector and it says not certified so I would not trust it beyond a meter or two for say 30min. Certainly make sure that failure does not allow water to wick up the tether and back into the rover.

My initial thoughts would be to twist and solder the wires, cover them in liquid electrical tape and then shrink wrap. This is similar to what was done for the original mods for the thruster motors.