What is an ROV?
The term ROV stands for Remotely Operated Vehicle. This is an underwater robot that allows the operator to remain in a comfortable environment while the ROV works in the hazardous environment below. ROVs are used in underwater enivironments to dangerous or deep for human divers to operate within. This makes them a useful tool in the field of Maritime Archaeology when surveying wrecks and other underwater archaeological sites. The ROV can vary in size from small vehicles with TVs for simple observation up to complex work systems , which can have several dextrous manipulators, TVs, video cameras, robotic grips, tools and other equipment.
Picture taken by Tom Jervis
The vehicle is powered from the surface through an 'umbilical' line that runs out the back of the robot. This limits the distance between the power source and the ROV but usually the permitted distance is sufficient for its tasks. To operate an ROV requires minimal staff personnel and is usually operated from a ship, however it can be deployed from docks and in some cases sea ice. The robot is very manouverable in the water making exploration alot easier. Depending on the size of the ROV the working depth may reach a maximum of 7,000 metres. However the smaller ones may be used in exploring sewers, pipelines and caves. The amount of time an ROV is able to remain submerged is only limited by pilot endurance, most dives are limited to 4 hours due to pilot fatigue. Piloting requires total and continuous concentration. Some projects will operate a shift system between pilots.
There are of course some problems when using an ROV. Mechanical maintenance is usually straightforward to repair however electronic maintenance requires extensive electronics knowledge. Spare printed circuit boards are kept on board to make any repairs required a much quicker process removing the need to return to shore. The leading cause of vehicle loss is entanglement. This is where the power line gets caught or trapped while the ROV is travelling underwater. This is a constant threat that the pilot must be aware of whilst operating. It is estimated that around 80% of power is drained through umbilical drag.
Pictures taken by Tom Jervis
There are many examples of ROVs being used in Maritime Archaeology. For example in 1985 at Loch Ness, Scotland a crashed WW2 Wellington Bomber 70m below the surface was surveyed using an ROV. It was too deep for a scuba survey therefore the ROV 'Sea Pup' was used in the process of its recovery. The Mary Rose fieldwork in 2003 included using an excavation ROV to remove the top layer of silt that had covered the wreck leaving the delicate excavation to be done by divers with airlifts.
There are training facilities for ROV pilots around the world. Theres one based in The Underwater Centre in Fort William on the shore of Loch Linnhe, Scotland. The job of ROV pilot entails much travel and mainly off shore based work. ROVs are not only used in Maritime Archaeology but also in the oil industry among others where they are used in laying oil lines and surveying the sea bed.
To see our ROV visit the HLF Engaging New Audiences page and look at our Mini ROVs.