Deep water Cutting

Anyone have knowledge on cable cutters for +200m work? Is there significant difference using rotary versus the hydrolic blades that are typically seen on ROVs?

What type of cable are you cutting? Wire? Fiber? What diameter?

Hydraulic blade cutters usually require an intensifier to raise hydraulic pressure to 10,000 psi. Rotary cutters can work from normal hydraulic pressure.

The problem with rotory cutters is the stability. When the blade start to cut, it will try to move the arm, and that can be a problem with a ROV.

Hydraulic cutters don’t have this problem, they lock on and then they cut.

Several mini-ROV manufacturers offer a manipulator that can cut smaller diameter rope / wire. Here’s one example:

Yes, I was thinking about that.

No definite material in mind, but interested in as to why the cutters I see
on the market are blade and not circular saw like. I suppose you can get
very high forces with the hydraulic option, and given the need to cut
steel, etc, that would be the choice I see being the best bang for the
buck, but these kits aren’t big, so attaching a hydraulic system seems a
bit too much…

I think you really need to define the rope / line to be cut before deciding on which cutting method to use. For mini / micro ROVs some sort of geared motor is usually the driving force that opens / closes the jaws of the manipulator, not hydraulics.

The other obstacle is how will the tool hold the line while it is being cut. The video above should give you some idea how difficult it can be to grab a line in any sort of current. There are other videos on youtube which might also be worth watching.