This is an interesting discussion and I generally agree with Anthony but hopefully some of these limitations will be reduced as products are developed. There are some that we might not be able to get away from - such as current speeds and power or inertia required to fight a current or maintain position.
What has been your experience operating the BlueROV in high currents? We find it can shoot off once deployed and it usually pulls a load of tether with it. The tether in the water column has to be adding to the drag. I found a brief examination of tether drag here. I don’t want to go into detail on it because it may be off topic but I calculate approx. 300N drag forces assuming 100 m of 8 mm tether in 2 m/s water current. The BlueROV has a max speed rating but I don’t think it accounts for the drag on the ROV or tether drag. For this thread, can anyone offer their experience with max currents the BlueROV can fight on battery? Is surface power supply the way to go for currents?