Drop/Clump Weight


Today I experimented with making a tow harness for my Trident. It is only temporary (and made of elastic bands!), but seemed to work, so will make something more permanent. I put two small bolts on the underside of the Trident to keep the bands spread apart so they didn’t obscure the camera.

I used a clump weight about 3 meters above the seabed, plus an additional 8 meters of tether, and we drifted at about 1 to 2 knots. This seemed to work OK. It kept the Trident pointing forwards, and allowed me some vertical control over the ROV.

Tidal conditions weren’t great because this weekend is one of the largest spring tides of the year (and we have a 10m tidal range), so the visibility was poor, and 1 to 2 knots is still much too fast. The combination of poor visibility and fast drift made it, on occasions, quite an exciting game of dodge the rapidly oncoming rock!

But, all in all, good progress. Next time I will wait for better visibility and a slack tide.


You might want to take a look at cmcp’s OpenROV Trident Top GoPro mount here to tie the tether to the top front of the Trident.


Just a reminder to anyone hanging a clump weight off their tether, to ensure it can break away if needed.

Recently I managed to snag my clump weight on a reef in about 30 meters and a 2 kt current. My break away was slightly too strong and it took a couple of minutes to break. Needless to say it was a very nerve-wracking few minutes as I thought I may loose my Trident!

I can confirm the Trident tether is very strong!