Best way to make a tether neutral or slightly negatively buoyant?

We’ve got the 4 twisted pair tether, and we are using it in seawater on a fishfarm. Unfortunately the tether is slightly positively buoyant in seawater, and this causes it to become tangled in a lot of the floating infrastructure on the farm - light cables etc. Can anyone suggest ways or things to add to the tether that will reduce its buoyancy?

Hi @HACker, welcome to the forum :slight_smile:

Our tethers will naturally lose a bit of buoyancy as the foam jacket absorbs some water, but they’re designed to be slightly positively buoyant in salt water, so it will be difficult to change that.

The main options I can think of are

  1. Add some form of clump weight that holds down the tether close-ish to the vehicle
  2. Use a different tether, that’s less buoyant
  3. Attach small weights along the length of the tether
    • This will likely cause it to be more prone to tangling, while also adding drag and making it harder to reel in and out
  4. Shave off part of the outer jacket
    • I can’t recommend doing this, but it would technically reduce the buoyancy

Cheers Eliot - I think that option 2 is going to be the option we will have to end up going for.