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ROVs for efficient underwater inspection

Ocean shipping continues to be the primary transportation method of billions of dollars in goods. As such a massive industry, safety is incredibly important. Underwater inspection of shipping vessels is important for many reasons. It saves money and time by understanding what is happening under your vessel without diver intervention. Underwater vessel inspections confirm that your hull is clear of barnacles and other marine life.

 

Underwater remotely operated vehicles or ROVs are submersible drones that allow users to conduct underwater vessel inspections under harsh environmental situations safely and efficiently. An ROV, or Remotely-Operated underwater Vehicle, is a submersible device fitted with sensors and sampling tools that is used to probe and collect data from depths too dangerous to send human divers.

 

Hull inspections have been traditionally carried out using dry docking.  However, taking your vessel completely out of the water when it is not required can waste a lot of time and money. From a financial, structural, and inspection code point of view it is important to inspect your hull between mandatory dry-dockings. With an underwater ROV you can get eyes underwater quickly and inspect vessel hulls at a moment’s notice – without dry docking. It allows proactive management of fuel efficiency by conducting regular ROV inspections of your hull to determine optimal cleaning and paint schedules.

 

While divers also offer an alternative to dry-docking there are potential downsides. In addition to the financial responsibility of hiring a professional diver, the time of hiring and scheduling said diver can be prohibitive. Perhaps most importantly, an ROV will keep humans out of harm’s way. They keep divers out of small, tricky or treacherous conditions by using an underwater ROV for vessel inspections.

 

These vehicles are ideal for scour inspections, confined spaces, deep water inspections, or deployment in any condition unsafe for diver entry. The use of an ROV system can dramatically reduce inspection costs while eliminating the risks associated with the use of divers to complete the task.

 

Remotely Operated Vehicles (ROVs) are extensively used for drilling, development, repair, and maintenance operations for offshore oil and gas exploration while overcoming the limitations of human subsea divers.  Often it is used for pipeline inspections, outfall inspections, and other areas that would otherwise use commercial divers.

 

The search for offshore oil and gas fields is leading companies to increasingly remote locations and lower depths, particularly in the North Sea. Thus, the need for ROVs to carry out routine tasks like surveys, seabed observations and inspection of the seafloor has increased. There are over 1,100 work-class ROVs servicing the global market at present. Heavy work-class ROVs make up 55% of the global supply, while medium and light work-class ROVs constitute 23% and 22% of the supply respectively.

Types of ROVs

A Remotely Operated Vehicle (ROV) is a mobile underwater vehicle that can be equipped with multiple electronic survey systems to aid in an inspection. They can be outfitted with HD video systems and sonar imaging equipment to navigate and collect valuable information.  These drones are able to navigate through underwater currents thanks to one or more propellers. They are generally equipped with cameras, obstacle avoidance sensors, and powerful lighting to record good quality footage even in dark underwater environments.  Most water drones are equipped with powerful headlamps, providing visibility in dark submarine conditions. Many of them also boast 4K cameras for high-quality image capture. Other common features and add-ons include FPV goggles, robotic arms, and ballasts.

 

These aquatic drones are predominantly tethered via a cable to a floating beacon or buoy at the surface. Cable tethering is necessary to get a live video feed from the drone and, more importantly, to ensure the drone doesn’t get lost in the abyss. However, some wireless underwater drones do exist.

 

ROVs are categorized into work-classes based on their weight, power, abilities and size. These are Micro, Mini, Light, Medium and Heavy work-class. Heavy work-class ROVs are more robust and capable of carrying out heavy-duty operations, such as construction and maintenance, and can guide subsea equipment for perfect installations.

 

Light work-class ROVs generally weigh between 100kg to 1,500kg and help in light construction work and underwater intervention. These ROVs can operate at depths below 3000m. Over the past decade, oil and gas companies have been heavily investing in research and development to create a new kind of heavy work-class ROVs, ones that are highly compact, versatile, cost-effective and operationally efficient. ini ROVs, which generally have a horsepower rating of less than 5HP and can perform inspection services much more efficiently than other conventional work-class ROVs or even human divers.

 

When compared with ROVs from higher work-classes, which require more specialized operators to handle, the cost advantage of Mini ROVs is very compelling. The acquisition cost of larger ROVs is significantly higher than Mini ROVs, who also have an edge in terms of operating cost and spare parts cost due to their versatility and compact size. They thus benefit from economies of scale, keeping the per-unit costs low.

 

The overall cost of ROVs are determined by their horsepower, sensors and the tooling mounted on the vehicle. Mini ROVs in the inspection category tend to be open frame models, which allow for extra sensors and small tool skids to be added when required. Thus, if the scope of work involves only inspection, the camera and navigational sensors alone may do the job, saving the trouble of installing other sophisticated tooling. For better underwater mapping and surveys in turbulent waters, where there is minimal visibility, there is also the option to mount imaging sonar, which can serve as real-time acoustic eyes for navigation.

 

Top ROV Companies

UNDERWATER DRONES WITH CAMERA BATTERY LIFE DIVING DEPTH 4K CAMERA TETHERED/WIRELESS RELEASE YEAR PRICE
Chasing Dory 60 min 15 m No Tethered 2019 $499
Chasing F1 360 min 28 m No Wireless 2020 $699
Geneinno Poseidon 300 min 100 m No Tethered 2019 $910
PowerVision PowerRay 240 min 30 m Yes Tethered 2017 $999
Chasing Gladius Mini 120 min 100 m Yes Tethered 2018 $1,099
YouCan BW Space Pro 300 min 100 m Yes Tethered 2019 $1,399
QYSEA FIFISH V6 270 min 100 m Yes Tethered 2019 $1,699
Aquarobotman Nemo 180 min 100 m Yes Tethered 2018 $1,799
ThorRobotics TrenchRover 120 min 30 m Yes Tethered 2019 $1,878
Geneinno T1 240 min 150 m Yes Tethered 2018 $2,499
Chasing M2 PRO 300 min 150 m Yes Tethered 2021 $4,999

 

 

EyeROV

Kochi-based EyeROV is working towards enabling efficient underwater inspection with its marine robotic solutions and solving problems for several industries, such as defence, ocean research organisations, shipping, oil and gas, infrastructure, and construction. Founded in 2016 by Johns T Mathai, and Kannappa Palaniappan P, EyeROV is developing India’s first commercial underwater drone for remote inspection of offshore assets.

 

In an earlier interaction with YourStory, Johns explained that underwater inspection was more challenging than land or air inspection because human divers have to deal with high water currents, poor visibility, and a hostile environment because of wild marine creatures. Apart from this, divers can only dive up to a certain depth. The founders felt that a remotely operated vehicle (ROV) could help solve these problems. “With human divers, there are either inspection delays or lack of expertise. They are able to dive only up to 30-40 metres, whereas an ROV drone can go up to 100 or 200 metres below sea level,” Johns explained.

 

The startup’s first industrial-grade underwater drone EyeROV Tuna was commercially launched in 2018. It claims the 50cm X 50cm X 50 cm cube-shaped ROV has completed more than 1,000 hours of underwater inspection of dams, bridges, ports, ship hulls, oil and gas assets, and other critical underwater structures across 25 projects in five states.

 

References and Resources also include:

https://www.gep.com/blog/mind/mini-rovs-are-making-underwater-inspections-cost-effective

About Rajesh Uppal

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