Hi, I tried to look for something similar to ROV GPS Seasam Navigator - locate your underwater inspection.
Basically we cannot operate the ROV from a boat because we do not have dynamic positioning and the sea bed is deep (about 100 meters). The ideal solution would use BlueROV2 combined with a buoy keeping position to which the tether cable would be connected. I looked into the BlueBoat but it does not seem to be built for dynamic positioning (that would need directional thrusters).
Any experience of such solution?
Hi @maurello -
Welcome to the forums!
The BlueBoat can do exactly as you wish, in terms of station keeping to hold a position in a body of water - this is called loiter mode and is documented in the operations guide.
When it comes to connecting a BlueROV2 to the BlueBoat, this is technically possible, but not commonly done (or recommended) for a few reasons. The primary reason is that the WiFi link from the BlueBoat to the BaseStation is typically insufficient for low-latency, freeze-free video connection to a BlueROV2 sharing the connection. From a logistical perspective, managing the tether from the BlueBoat is also a significant challenge, as you certainly don’t want it to get fouled up in or damaged by the propellers!
100m is really not very deep, assuming you have at least a 150m to 200m tether. Most users attach a clump weight of 5-10lbs to the ROV tether some distance from the ROV, this can help overcome currents and keep the ROV directly below the boat it’s being launched from.
Maybe it would be easiest to have a BlueBoat holding position serve as a visual reference for a captain piloting a boat you launch the BlueROV2 from?
A DVL like the WaterLinked A125 equipped onto the BlueROV2 could actually lock onto the bottom from 100m overhead, and make descending without drifting more than a few meters from the surface straight down quite easy!
Thanks for the reply!
We normally drop a shot line when we find a wreck, so we have a clear visual reference for the site. The challenge is keeping a small support boat in position to run an ROV in open water: At 100 m depth, we can’t anchor; we usually drift while divers descend and we adjust position near the buoy. With depth and cable slack, even a 300 m tether probably gives only ~150 m of workable radius around the wreck. Moving the boat with lots of tether in the water is a recipe for prop entanglement, unless someone is constantly taking in slack on the spool.
Is there a recommended way to operate an ROV from a drifting boat that must maintain position by manual maneuvering, without risking prop fouling on the tether?
Hi!
We do that kind of work a lot.
You need underwater positioning and a boat that can go very slow.
UW positioning can be Waterlinked SBL system or a USBL system.
By giving the skipper of the boat a screen with ship position, ROV position and waypoints there is possibility to manually hold position for a skilled skipper.
Since the movement is small you need a ship that can go as slow as 0,5 knot or less.
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If I understand correctly you basically integrate the Waterlinked SBL to BlueROV2. Then you integrate Waterlink SBL also to the ship plotter (?). Is there a specific plotter that allows such integration?
Hi @maurello -
I believe @Boko was referring to using an external chart plotter that can display icons when receiving a position stream (NMEA typically?)
It is possible to show your topside position, as well as the vehicle position, in both QGround Control and Cockpit, if a GPS is connected to your control computer, and the Autopilot in the vehicle knows its GPS position….
Hi, this can easily be achieved using a trolling motor on the service boat on the surface.
The trolling motor often has built in gps that can hold the position of the boat quite accurately.
It’s often used in the US when fishing in lakes and rivers.
Regards,
Jan R