As Remotely Operated Underwater Vehicle (ROV) technologies and capabilities have improved, the offshore industry has come to rely on them for drilling support and subsea construction services to enable deepwater exploration. Some ROVs carry out operational functions at extreme depths up to 10,000 feet. ROVs can remain underwater for long periods of time, and may also be operated in conditions that would hamper diving operations.
In the splash zone, however, the area immediately above and below the surface area, wave action, and tidal forces can make it challenging to operate ROVs. Inspections and maintenance work in the «non-accessible» area requires specialized and robust splash zone tools that are constructed for harsh marine environments.
OceanTech’s robotic solutions are specifically designed for access to underwater areas where ROVs aren’t able to operate safely. As the splash zone tools are securely attached to the platform or structure, they can perform work in the entire splash zone without being affected by waves and strong currents. As opposed to ROVs, which may be at risk when operating in confined spaces, there is a low probability of damage to our splash zone tooling. Once deployed, our operations can continue in up to 3 meters of wave height (Hs), and perform precision work in adverse weather conditions.
Our techniques and robotic solutions can be utilized for all splash zone and underwater constructions, including steel structures, mooring systems, pipes, rubber structures, risers, fish farming nets and monopiles.
One of the advantages of ROV operations over other conventional methods is the fact that you don’t need any personnel underwater. The umbilical provides an unlimited power supply, allowing operators to use the ROV for as long as they desire. The same umbilical could, however, also be a disadvantage because of drag and motions.
Strong currents, and high waves, in particular, are a real challenge if the thrusters aren’t strong enough. Severe conditions may also cause negative impacts on the power supply, which can lead to more frequent failures. This induces challenges as a stable power supply is a prerequisite for systems such as ROVs. In extreme situations, ROV operations may have to be called off to minimize risk of damage to the equipment.
These challenges can result in limited weather windows, operational inefficiencies, and costly delays. The planning of ROV operations in the splash zone is highly dependent on predictable weather.
By contrast, our robotic solutions provide a far greater window length and simplify the planning process. By eliminating standby time while waiting for favourable weather conditions, we reduce both time and costs throughout the entirety of the project. This also means it’s easier to plan activities before work starts, and schedule projects more accurately in terms of start and finish dates. Additionally, as there’s no need for ROV vessels to be kept on standby, our solutions reduce CO2 emissions significantly.
ROV operations require support vessels, cranes, and large crews. The ROVs vary in size, from small vehicles with video cameras to more complex and heavier systems, and generally weigh between 500 and 5,000 kg.
OceanTech’s rigging equipment is lightweight, and our rigging practices are less labor-intensive than ROV operations. As we utilize temporary lifting equipment topside, there’s no need for support vessels such as crane vessels during installation. Our splash zone tooling is installed from the platform, and controlled from a purpose-built control unit on the topside of the platform. We can also handle heavy loads with our lifting equipment. Previous projects include handling 60 tons using temporary rigging and lifting equipment.
The standard equipment for our splash zone operations consists of three units: A Hydraulic Power Unit (HPU), a control cabin, and a container carrying lifting equipment and splash zone tools. The equipment can also be used for the rigging of common components including clamping units and anodes and is generally lightweight. This means that small crews of three to six platform-based personnel are sufficient for most projects. Qualified OceanTech access technicians are always present during operation. We handle all rigging and lifting activities, including lift plans and calculation of suspension points, and have a proven track record of successfully completing installations and operations in the splash zone worldwide.
ROVs can last years without the need for major repairs, but purchasing, ROVs can cost anywhere from a few thousand dollars to millions of dollars. These costs are reflected in high contract charges. In addition, there are costs related to personnel, support vessels, and equipment.
For operations in the splash zone, OceanTech’s robotic solutions are a more affordable option than ROVs. We are less weather dependent, avoiding time-consuming and costly standby time and delays, and offer considerably lower daily rates.