Owners of offshore support vessels considering reactivation of laid up assets must satisfy multiple safety and operational issues before class is restored
Increased demand for production units means there are some positive signs from the OSV market, leading to increased reactivations of[ds_preview] laid-up vessels as new and delayed contracts are awarded. While not all of these vessels will re-enter the active fleet, the topic of reactivation has become more popular as the recovery in the oil price continues and operators seek to position themselves to capture the potential upside.
Asset owners need to carefully consider their options before reactivation. Among the issues to be considered are the vessel’s age and its level of quality in terms of equipment and technology; whether it is warm or cold stacked also drives the decision. Reactivation is ultimately an economic choice for the owner and is likely to be based on the cost of the process versus the length of a potential service contract. Lead times are short because multiple vessels are in competition for the same work and the degree of readiness can vary widely.
Different owners will have applied varying levels of technical capability during the lay-up and whether this process is done with a reactivation plan, as well as the quality of the preservation itself will have an impact. Financial risks include the total cost of work to be done, including transportation of teams to the facility to perform the work or to the vessel. The reactivation timescale can include the availability of materials, the readiness of class, flag and vendors to support as well as software and automation plans.
Modern OSVs can include complex technology such as dynamic positioning, power management and control systems which must be brought up to date. Software must be upgraded and IT systems will need new cyber security measures.
Structural issues can include hull condition, corrosion, wastage and the replacement of parts. It is not unusual to find doors and hatches rusted and corroded and general corrosion on deck, in ventilators and air pipes.
The vessel must be checked for unapproved modifications and replacement of outdated or missing parts. The owner must understand the duration of the survey, whether to undertake a Failure Mode Effect Analysis and whether the vessel will require an audit under the International Safety Management Code, or the International Ship and Port Facility Security Code. An interim audit will be required by the vessel’s flag state if the unit has been laid up for more than six months.
In the years since the downturn in the oil price, OSV operators have lost more than vessel capacity. In many cases they also lost people, a base of technical knowledge and expertise that could be vital to restarting vessel operations. This is the technical void that class aims to fill.
Key factor wind farm development
Developers of offshore windfarms face a number of challenges in addition to the environment in which they are constructed. These include the regulatory regime that lays out strict rules on cabotage trade and safety requirements that encourage the concept of ‘walk to work’ for technical teams working on the construction and during subsequent maintenance.
New wind farm development is also driving the flexibility of vessels that support installation, operation and maintenance, with construction jack-ups typically of four-leg design rather than the familiar three in the oil and gas sector.
Specialised tonnage
In comparison to traditional offshore wind service operations using crew transfer vessels or helicopters, an SOV promises a range of operational benefits for both windfarm operators and service teams, including enhanced safety and comfort for technicians; accelerated on-site service; increased weather availability and improved productivity.
The biggest safety challenges in offshore turbine service work arise from the use of CTVs, which are the traditional means of transferring technicians to and from the wind turbines. The gangway system (which employs motion compensation system to keep it in a fixed position relative to the turbine) reduces the risk in crew transfers, can operate in almost any weather conditions, and can cope with high wave heights. However, the main advantage that an SOV offers is the ability to concentrate skills and resources; because the service team and technicians can be based offshore, no additional travel time to or from the wind farm is necessary.
With warehouse space immediately below the main cargo deck, SOV carries almost every spare part the project requires in order to respond quickly to component failures and minimize turbine downtime. In addition to the hydraulic gangway arrangement, an SOV provides further flexibility by acting as the Mothership for an additional Safe Transfer Boat which can also be used to move technicians to and from the wind turbines in a range of different weather conditions.
Battery system
Seacor Marine requested the ABS BATTERY-Li notation for »Seacor Maya«. Modifications to the OSV were completed in May 2018, upgrading »Seacor Maya« to use lithium battery power. The lithium-ion battery energy storage system is designed to keep the generators running at between 75% and 80% of the maximum continuous rating. At higher power demands, the batteries supply power and, at lower power demands, the generators recharge the battery. The Corvus batteries are enclosed in a 20’ container with a weight of approximately 28t.
Assessing the energy storage system of a precedent-setting hybrid-electric power system such as on SEACOR Maya is a complex process. The systems allow for use of alternative energy sources, which can store energy as a backup for the main power source. Part of their attractiveness is that they can enhance safety by allowing a response to emergency scenarios where all main power is lost.
Wei Huang
