On Tues 19 Nov after the Marine Technology Research Unit research day a small team of us went to the Ipswich Scuba pool to try out the 2 Fifish ROVs that had been kindly loaned to us by Mantsbrite. We didn’t have long in the pool but enough time to test out the manoeuvrability and functionality of the grabber.
Comparing the 2 ROVs for assembly from the flight cases, the E-Go was quicker and easier to put together using quad locks. The V6 Expert requires 3 small bolts to be used to attach the grabber, with a possibility of losing them if you’re rolling around on a boat on the way to the job. The tethering system was nice on both units but it could do with some marks to line up the keyway on the wet connectors. We only used the grabber but the E-Go could also accommodate another accessory on the top. We also mounted the Q-DVL under the grabber and used a splitter to double the wet link connection. The 100m tether is much smaller and lighter than the 200m reel, which would be a consideration if you’re thinking of travelling with the units. The newer 200m reel had a wet connector on the reel end which allows for complete disassembly and seemed better designed.
You can use any smart phone as a controller screen but we had a couple of Lenovo M8 tablets available from another project and they fit the screen holder perfectly giving us a massive view screen and comfortable UI for controls.
Launching of the units was straightforward using the rear handle and tether. As we had divers in the pool as well as ROVs one of the team was on tether duty, ready to reel in any robots that strayed too close to the humans. We also noticed that the tether is slightly positively buoyant which made cable management a bit easier than negative (which our other unit has).
The controls can be setup for different pilot profiles. Jon preferred the gaming configuration whereas Russ, more familiar with flying UAVs, switched to US drone pilot mode. The interface was very nice, in particular the ability to control the power profile allowed us to dial down the power so the units didn’t accidentally run away from us. The interface is the same for both units so if you’ve learnt one, you can drive the other. We dropped a 1kg weight belt into the pool to recover. It was straightforward to use the grabber to grab the weight belt but a bit more tricky to bring it to the surface. The V6 Expert just about managed by dragging it up to the surface but the E-Go comfortably brought it up in a horizontal position. The latter just has a bit more power available for this kind of thing. The vision lock was also an interesting feature we’ve not used before on ROVs.
In conclusion, both units are excellent. The V6 Expert wins on price, being about half the cost of the E-Go, but the E-Go is a significant hardware improvement, with more power, more functionality and more thought to how people will actually use them in the field. If money were no object, an E-Go would be a worthwhile investment. For those on a budget or just getting started, the V6 Expert is sound choice compared to other brands of ROV in the same price and functionality bracket.