| Written by Mark Buzinkay
Table of contents:
- A short history of the Offshore Wind Farm Service Vessel
- The Technology That Drives The Offshore Wind Farm Service Vessel
- The North Sea Giant
- FAQs
- Takeaway
- Glossary
A short history of the Offshore Wind Farm Service Vessel
As offshore exploration began in the 1960s in the North Sea, it was mostly limited to shallow waters and coastal regions due to economic and technical reasons. In other words, it was easier and cheaper to build any kind of structure, quite close to the shore. Traditional maritime vessels or CTVs (Crew Transfer Vessels) could easily reach these regions for supplies and crew changes because they could get back to shore easily. In the 1970s, throughout the 1990s, though, the industry pushed the frontiers of exploration further as shallow reserves dwindled and oil and gas demand spiked. Deep-sea operations present a lot of new challenges as we move from coastal to deep-sea operations. There are harsher conditions and greater depths in deep-sea operations compared to the relatively calm and predictable environments close to shore. For the industry to operate for extended periods, it needed a new kind of support vessel capable of enduring the high seas and providing a base of operations. Offshore drilling technology and sea infrastructure were transformed during this period.
The logistics of supply and personnel transport became increasingly complicated and expensive as exploration moved further offshore. Helicopters could transport people; however, they couldn't transport light cargo due to weather conditions, range, and payload. The need for a more sustainable and reliable solution led to the conceptualisation of vessels that could provide direct support to offshore operations, incorporating living quarters, storage, and workshops. For deep-sea operations, vessels needed better capabilities: dynamic positioning systems to stay on station without anchoring, which could damage the seabed or be too hard in deep waters; robust hull designs for rougher ocean conditions; and longer deployment endurance. These requirements gave birth to the first generation of SOVs, which were essentially modified versions of existing ship designs.
In the beginning, in the 1960s, offshore vessels were not built from scratch; rather, they were modified from existing ones. To meet the immediate needs of the offshore industry, supply boats, tugboats, and even fishing trawlers were repurposed. There was extra fuel capacity, storage for supplies, and cranes to lift heavy equipment added. Additionally, crews working on offshore platforms were housed in accommodations that were added or expanded. This was just an interim solution, though. Early SOVs lacked specific features that would make them efficient for offshore support. The industry recognised that purpose-built vessels were needed because these vessels had limitations.
In the later years, purpose-built SOVs incorporated lessons learned from early adaptations. They were better at sea, better at navigation, and better at accommodation during long stints at sea. They also integrated helidecks to boost their operational versatility. The emergence of SOVs changed the offshore industry forever. Exploration and maintenance became easier, safer, and longer because of them. Those vessels have become more sophisticated as offshore energy projects develop, incorporating new technologies in marine engineering and environmental sustainability.
The Technology That Drives The Offshore Wind Farm Service Vessel
The evolution of SOVs has been profoundly influenced by a suite of technological advancements in marine engineering. These developments have not only augmented the efficiency and safety of vessels but have also considerably broadened their operational scope. Innovative hull designs have played a huge role in it. Modern vessels have advanced hull designs, including multi-hull structures and wave-piercing bows. Especially in the North Sea's challenging conditions, these designs offer excellent stability and seaworthiness. They also reduce fuel consumption and improve motion performance, so it's good for both the environment and the economy.
In marine engineering, hybrid propulsion systems combine the reliability of diesel engines with the efficiency of electric motors. The diesel-electric propulsion is a type of conventional propulsion system where the main engine's power is converted into electricity through generators and used to power the propeller shaft instead of a direct mechanical drive in conventional diesel propulsion. Many modern designs use battery power to supply technologies like Dynamic Positioning Systems or thrusters, and other things like deck cranage, cargo equipment, pumping, air conditioning, and hotel loads (internal electrical power required for day-to-day operations). A spinning reserve is when the battery load completely replaces or substitutes the main engine load. With high-strength, corrosion-resistant materials, the vessels have last longer, while modular construction techniques made it easier to build. With this approach, you can design vessels more customised and deploy them faster. A Dynamic Positioning (DP) system keeps the vessel in position despite wind, waves, and currents by using complex algorithms and sensors. For precise operations in adverse weather conditions, modern DP systems are key.
High-speed satellite communications have brought about a revolution in the way SOVs maintain connectivity with shore bases and other maritime entities. This technology guarantees continuous communication flow, which is vital for the coordination of operations, safety management, and maintaining the morale of the crew through regular contact with family and the outside world.
With GPS, radar, and electronic chart display and information systems (ECDIS), modern vessels are equipped with the latest systems. Crew members get real-time info on the position of the vessel, surrounding sea depth, and navigational hazards, so they can navigate the North Sea safely. Automatic Identification Systems (AIS) deliver vital information like their position, course, and speed to nearby vessels and coastal traffic monitoring centres. Integrated Bridge Systems (IBS) help prevent collisions and manage traffic efficiently in busy sea lanes, which is a big improvement in maritime safety. This system centralises control by integrating various navigational and operational systems into a unified interface, reducing human error and facilitating decision-making on board. Using Internet of Things (IoT) technology and sophisticated sensor networks, SOV operations are now managed remotely. They can monitor engine performance and fuel consumption remotely. By doing this, you can keep the vessel reliable and efficient.
So, let's see some examples of the vessels, operating in the North Sea:
The North Sea Giant - A True Giant of an Offshore Wind Farm Service Vessel
With a length of 156m, North Sea Giant is one of the world's longest offshore construction vessels (OCVs). Owned by North Sea Giant AS, the vessel is designed for umbilical and mineral extraction-related construction.
In August 2008, Metalships & Docks laid the keel, launched it in August 2009, and delivered it in April 2011. The vessel was constructed in Vigo by Spanish shipyard Metalships & Docks. Turkey's RMK Shipyard manufactured the hull. Sawicon, a ship design and engineering firm based in Norway, designed the vessel, while Novenco provided the HVAC plant.
There's a clean design notation on North Sea Giant and comfort class 3 on it. It's meant to reduce emissions and discharges during operation. Due to its complete diesel power plant, the vessel consumes less fuel compared to other vessels in her class. It has high redundancy features based on the low-loss concept (LLC) diesel-electric system.
Besides the 23m diameter helicopter landing platform on the bow, the vessel has a 500 m2 bridge on the sixth deck and 2,950 m2 of working deck, plus 750 m2 of closed area. It has a load capacity of 10t/m2. It has 2,000 m3 of fuel oil, 1,000 m3 of fresh water, and 8,000 m3 of ballast water. There's also a moon pool that's 7.2m x 7.2m and is ROV-ready.
To keep the vessel from heeling caused by loading and unloading cargo, each side of the vessel has a Frank Mohn (FRAMO) anti-heeling pumping system. FRAMO anti-heeling system consists of a reversible propeller pump with an electric motor, a control system with an inclinometer, level switches, a butterfly valve, and an electric starter. To keep the vessel stable during waves, a passive stabilisation tank and an active anti-roll system are installed. It weighs 35,792 tons. Gross tonnage is 18,151 tons, and net tonnage is 5,446 tons. There are 156m in overall length and 144m between perpendiculars. A moulded breadth of 30m, a depth of 10.7m, and a draft of 7.5m respectively.
A total of 120 people can be accommodated on board the vessel. The cabin combination comprises 58 single cabins and 31 two-man cabins. Onboard facilities of the vessel include two recreation rooms, a cinema hall, Heli reception, an online/offline room and a conference room. There are eight offices, two ROV control rooms and two ROV garages.
The vessel is equipped with two large offshore cranes. The first one is a Hydramarine knuckle boom crane with a maximum lifting capacity of 400t at a 10m radius. The second one is also a Hydramarine knuckle boom crane, but with a maximum lifting capacity of 50t. The vessel also has a provision crane whose maximum lifting capacity is 2t.
The deck machinery includes two electro-hydraulic capstans and two electro-hydraulic anchor mooring winches. North Sea Giant is furnished with diesel-electric propulsion systems comprised of six General Electric (GE) main engines, each producing 3,630kW at 900rpm, and six Leroy Somer main generators. There is also an emergency engine of 600kW capacity. The propulsion for the vessel is provided by three Voith Schneider main propellers of 3,800kW each. The manoeuvring system comprises two Voith Schneider forward thrusters, each of 3,800kW, and a Rolls-Royce tunnel thruster of 2,000kW capacity. The vessel has Kongsberg's DPC21 dynamic positioning (DP) Class-3 control system for automatic heading and positioning.
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FAQ Offshore Wind Farm Service Vessel
What is a Service Operation Vessel (SOV) in offshore wind operations?
A Service Operation Vessel (SOV) is a purpose-built ship designed to support the installation, maintenance, and operation of offshore wind farms. It serves as a floating base for technicians, offering accommodation, workshops, storage, and advanced navigation systems to remain stable and positioned near wind turbines for extended periods.
How do SOVs maintain their position at sea?
Modern SOVs use Dynamic Positioning (DP) systems that rely on GPS, sensors, and thrusters to automatically maintain a fixed position and heading, even in rough sea conditions. This allows safe transfer of personnel and cargo to and from wind turbines without anchoring.
How do SOVs ensure crew safety during offshore operations?
Safety is a top priority on SOVs. Electronic Personnel on Board (e-POB) systems track who is on the vessel in real time and update the POB list in real time. e-Mustering digitises emergency drills and responses, ensuring everyone is accounted for quickly. Access Management controls who can enter critical areas, helping prevent accidents and unauthorised entry.
Takeaway
Service Operation Vessels have become indispensable in the offshore wind industry, evolving from simple support craft into high-tech platforms designed for complex, long-duration missions. Their advanced propulsion, navigation, and connectivity systems ensure efficiency in even the most demanding sea conditions. Just as crucial is the focus on safety: modern SOVs integrate electronic Personnel on Board (e-POB) systems, digital mustering, and controlled access management. These technologies provide real-time crew tracking, streamline emergency response, and enhance operational security—making today's offshore operations not only more efficient but also significantly safer for everyone on board.
Delve deeper into one of our core topics: Personnel on board
Glossary
Deep-sea operations refer to industrial activities conducted far from shore, typically at ocean depths greater than 200 meters. These operations include offshore drilling, wind farm construction, subsea cable installation, and marine research. They require specialised vessels, equipment, and technologies to withstand high pressure, strong currents, and remote conditions. Deep-sea operations are critical for energy production and infrastructure but also raise environmental and safety concerns.
References
(1) M. Buzinkay & M. Wozniakowski-Zehenter (2025): The Journey. Life and Work on a SOV.
(2) Jahn, F., Cook, M., & Graham, M. (2008). Hydrocarbon Exploration and Production. Elsevier.
Note:
This article was partly created with the assistance of artificial intelligence to support drafting. The head image was generated by AI.
