Oils and gas are still our most important

Oils and gas are still our most important sources of energy

OFFSHORE ACTIVITIES VESSEL/UNIT IN OPERATION 1. Seismic surveying • Seismic surveyor 2. Exploration & production • Drilling units: jack-ups, drilling semisubmersibles, drillships 3. Construction & installation • Crane vessels, offshore of production platforms barges, heavy-lift carriers 4. Linking production wells • Pipe-laying barges or pipewith production facility laying vessels • Fixed platforms, tension leg 5. Production platforms, FPSO, FSO 6. Transportation to shore • Shuttle tankers, pipelines laid by pipe-laying vessels • Suppliers, anchor handlers, 7. Supply and services fast crew boats 8. Maintenance and repair • Multipurpose, construction, diving, ROV support vessels, jack-up maintenance rigs 9. Watch keeping • Standby and chase vessels

1. SEISMIC SURVEYING SEISMIC SURVEY VESSEL The purpose of this vessel is to produce detailed information for oil companies as a basis for actual production drilling. To obtain this information sound waves are initiated by means of air guns, the reflections are collected by detectors within long cables (streamers) towed by the vessel.

SEISMIC SURVEY VESSEL Seismic survey vessel in drydock Seismic survey vessel in operation

2. EXPLORATION AND PRODUCTION DRILLING Drilling units: v. Jack up drilling rigs v Semisubmersible drilling rigs v Drilling ships

JACK-UP DRILLING RIG Jack-up rig is a type of offshore mobile oil or gas drilling unit that is able to stand still on the sea floor resting on a number of supporting legs. Jack-ups provide very stable platforms for drilling purposes, but can only be placed in relatively shallow waters. Typically they are used in 120 m water depth, although some designs can go up to 170 meters. While some jack-ups are capable of self-propulsion, most of them are transported by tug boats, submersible barges or heavy-lift transport. Jack-ups may be triangle- or rectangle-shaped. 3 - legged barges are for exploration drilling, 4 -legged barges are for construction work.

JACK-UP DRILLING RIGS 1. Derrick, 2. Helideck, 3. Drill floor and wind wall, 4. Leg, 5. Deck cranes 6. Deck house or accommodation. 7. Monkey platform, 8. Deck, tanks and work spaces

SEMI-SUBMERSIBLE DRILLING UNITS Jack-up rigs cannot be used on depth over 170 -190 m. So, another kind of drilling rigs was developed – semi-submersible drilling rig.

SEMI-SUBMERSIBLE DRILLING UNIT v v v A semi-submersible platform, or rig, is a mobile structure used for drilling exploration and production wells in 150 -2, 500 m water depth. The unit is supported by columns sitting on hulls or pontoons. When in operation, the pontoons are filled with water and lowered beneath the surface. The installation is normally kept in position by a number of anchors but may also be fitted with dynamic positioning equipment. Semi-submersible rigs provide excellent stability in rough and deep seas. Anchored units can operate in max. 1, 500 meters. DP units can operate independent of water depth.

SEMI-SUBMERSIBLE DRILLING UNIT The rigs can be moved by tugboats or can use own thrusters for moving. Brand new semisubs can reach the speed up to 8 knots. In case of faster mobilization needed, they can be transferred by heavy-lift boats. An important advantage in comparison with shipshaped type drilling vessels is better motion behaviour of the unit in harsh environments, which can give an extended working window.

SEMI-SUBMERSIBLE DRILLING UNIT Towing of a SSDU by a tug boat

SEMI-SUBMERSIBLE DRILLING UNIT 1. Drilling derrick 2. Deck 3. Columns 4. Cross brace 5. Diagonal brace 6. Anchor racks 7. Anchor winches (on corner edges) 8. Lifeboat station 9. Deck cranes 10. Floater

DRILLSHIP A ship-shaped drilling ship has been designed with a drilling plant. It is most often used for exploratory drilling of new oil and gas wells in medium to deep water – 150 -3, 000 m or for scientific drilling. Drillship can also be used as a platform to carry out well maintenance or completion work, such as casing and tubing installation or subsea tree installation. It is ideal for drilling consecutive wells in different parts of the world.

DRILLSHIP To maintain position during drilling operations, the ships are either anchor moored with 8 or 12 anchors or long wires and chain, or rely on DP depending on water depth. They may use thrusters plus DP system or thrusters and anchor winches are selected in addition to DP system. Drillships fitted by anchors are cheaper, but can operate at a limited depth. They also require assistance from anchor handlers – to install anchors in desired position.

DRILLSHIP The greatest advantages of modern drillships are their ability to drill in water depth of even more than 3, 000 meters and the time saved sailing between oilfields worldwide. Some drilling ships can be equipped with two drilling towers (dual derrick type) to perform drilling operations faster.

DRILLSHIP 1. Drilling derrick, 2. Drill floor, 3. Riser and pipe storage, 4. Supply handling crane, 5. Accommodation/ helideck 6. Life boat station

3. CONSTRUCTION AND INSTALLATION OF PRODUCTION PLATFORMS / UNITS CRANE VESSELS v v v These are ship-shape and semisubmersible barges or vessels, equipped with one or two heavy-duty offshore cranes. Because of their increased stability, the largest crane vessels are catamaran or semisubmersible types, but conventional monohulls are used too. Crane vessels are specialized in lifting heavy loads. They transport and install large topside modules (weighing up to 12, 000 metric tons) of fixed offshore platforms. The base of the platform called jacket is either launched from a barge or lowered onto the seabed by the crane vessel prior to installation of the topside modules. After the jacket has been installed, it is firmly connected to the seabed by large hydraulic hammers suspended from the offshore cranes.

v Recently crane vessels have come into use for the removal of offshore platforms when the oil/gas reservoirs are depleted. v Crane vessels may also have pipe laying facilities.

HEAVY LIFT PIPELAYING VESSEL This is a combination of a pipelayer and a ship for offshore installations in general. The ship is provided with equipment for pipe-laying and with a crane with a lifting capacity of 3, 000 tons. The pipelay installation is fitted below deck. This can be seen from the stinger which is fitted low at the stern. This reduces the pipe movements when the ship is rolling.

HEAVY-LIFT VESSEL (FLOAT ON/ FLOAT OFF) A heavy-lift ship is a vessel designed to move very large modules that cannot be handled by normally equipped ships. They are of two types: semisubmerging, lifting another ship out of the water and transporting it (commonly known as “flo/flo” for float on/float off) and vessels that augment unloading facilities at inadequately equipped ports. Semi-sub vessel fills up ballast tanks to lower the well deck below the water’s surface allowing oil platforms, other vessels, or other floating cargo to be moved into position for loading. The tanks are then pumped out, and the well deck rises to shoulder the load.

HEAVY-LIFT VESSELS

OFFSHORE BARGE Another name for this unit is work accommodation barge, or floatel. Most work barges are made to support drilling rigs, FPSO and production platforms. As fixed platforms have a limited number of living quarters, floatels accommodate and cater for the personnel constructing and operating these units. They are also used as hotels for extra personnel. So, you can find gym, swimming pool, cinema room, conference rooms and offices, billiards, cafes, library, hospital on board. Such barges commonly have wide deck free space for temporary storage materials from the mother unit.

OFFSHORE BARGE Work barges are often equipped with a heavy lift crane with a huge crane boom. This crane is used to lift and transfer deck cargo between the barge and the mother unit. Barge is secured by anchor or can be positioned by thrusters using DP system enables the barge to come right up to the platform and embark or disembark the personnel by means of a hydraulically-driven telescopic crane. If weather conditions hinder the barge from being maintained in position by DP system, the personnel is delivered by surfer boats. An important design feature of the barge is availability of a helideck. Barges can be used for a wide range of other marine tasks: firefighting, pipelaying, diving and ROV support operations.

OFFSHORE BARGE Some of the floatels are connected to the mother unit by special walkway bridge.

4. LINKING PRODUCTION WELLS WITH PRODUCTION FACILITY PIPE-LAYING VESSEL For the installation of subsea oil/gas pipelines various barges and vessels are used: anchored or DP flat bottom barges, semi-subs and ship-shaped vessels. Pipes are supplied to a pipe-laying vessel by PSVs or pipe-supply carriers. Heavy-duty cranes on the pipe-laying vessel unload the carrier and hoist the pipe sections into temporary pipe-storage racks. After welding, the pipe sections are tested, and joined pipes are transported to the pipe stinger used in both shallow and deep water. The stinger is a guidance beam preventing the pipe from buckling directly behind the barge, guiding the pipeline into the water, and then lowering it onto the seabed.

S-LAY PIPE-LAYING VESSEL The S-lay system involves welding the pipe sections together horizontally, leading the pipe aft horizontally and then downwards over the stinger towards the seabed. Pipes are laid to a depth of 1, 000 meters.

J-LAY PIPE-LAYING VESSEL The J-lay pipe installation puts less stress on the pipeline due to J-tower which allows welding, coating, testing and lowering in a vertical manner. The shape of the pipe hanging in the water resembles a hockey stick, or the letter J. The J-lay pipeline can withstand more motion and underwater currents than pipe being installed in the S -lay fashion. But the pipelay process is much longer: 1 -1, 5 km per day against up to 5 km per day on S-lay. Also, the J-lay method gives a big bending angle on shallow waters, therefore it is not used at small depths. Pipes are laid to depths of 2, 500 meters. A very efficient installation system is the Reel vessel method which is suitable for cables, flexible pipes (they generally have a small diameter) and smalldiameter rigid pipes (40 cm).

REEL LAY PIPELAYING VESSEL

COMBINED REEL-LAY AND J-LAY PIPE-LAYING VESSEL 1. J-lay tower / Reeling ramp 2. Storage reels for flexibles/ rigid reeled pipe line 3. Pipe rack for rigid pipe sections 4. Board crane 4, 000 ton capacity 5. Accommodation / helideck / lifeboat station

5. PRODUCTION FIXED PRODUCTION PLATFORM Production platforms provide a working unit for production drilling and oil/gas production. They are also considered as the starting point of the pipeline extending to the collecting unit. They are prefabricated onshore, transported on barges lying on the side to their production locations at sea, and launched from the barge into a vertical position on the seabed. Then they are fixed to the seabed by piles with the help of a floating offshore crane. Modules are afterwards lifted onto the platform. These platforms are built on concrete and/or steel legs anchored directly onto the seabed, supporting a deck with space for drilling rigs, production facilities and crew quarters. Such platforms are, due to their immobility, designed for a very long-term use. Fixed platforms are economically feasible for installation in water depths of up to about 520 meters.

FIXED PRODUCTION PLATFORM The platform can be subdivided into the following compartments: steel jacket or concrete substructure deck modules drilling derrick helideck flare boom Steel jackets are vertical sections made of tubular steel members, and are usually piled into the seabed. Modules are fitted on top of a jacket. They are prefabricated box-shaped structures that are to be interconnected after fixing them permanently to the jacket.

TENSION LEG PLATFORM (TLP) TLPs are also assembled onshore and towed to their destination. Like fixed platforms, they are used for drilling and production of oil and gas. The unit resembles a semisubmersible drilling unit and is attached to the sea floor with tensioned steel cables. The buoyancy of the platform applies tension to the cables. The advantage of the TLP is economical aspect compared to fixed platforms; they are specifically for deeper water – greater than 350 m and less than 1500 m. In case the production in particular field goes down, this platform can be moved to other locations.

TENSION LEG PLATFORMS (TLP) Moses TLP Sea Star TLP

FLOATING PRODUCTION STORAGE AND OFFLOADING VESSEL (FPSO) This is a floating vessel installed on or in close vicinity of an oil and/or gas field which produces crude oil from hydrocarbons pumped from the oil wells. On the vessel hydrocarbons are processed, and oil is temporarily stored until it is offloaded onto a shuttle tanker, or, less frequently, transported through a pipeline. Mostly, an FPSO is able to move to worksite by itself, using own propellers, but there also not self-propelled units that have to be assisted by tugs. Conventionally, an FPSO is kept in position by a spread anchor mooring system. In deep water, DP system with azimuthing thrusters is used. In addition to a large amount of different pipes, valves and other equipment on deck, all FPSOs are equipped with flare boom used to burn redundant gases that are generated during production process. Usually FPSO is connected to subsea with a special turret, so the vessel will find a stable position weathervaning around the turret according to prevailing winds, waves and currents, which minimizes the loads on the FPSO.

FPSO The turret is a vertical tube, going through the ship, from above deck to below the flat bottom, around which the whole FPSO can turn freely. The flexible pipelines called risers that bring hydrocarbons to the surface are connected to the turret from below. 1. External turret (pivot point) 2. Flare tower (100 m high) 3. Gas lift compression modules 4. Crude separation modules 5. Pipe generating modules 6. Water injection treatment module

FPSO WITH SHUTTLE TANKER BEHIND 1. flare boom, 2. topsides, 3. offloading hose, 4. shuttle tanker

FLOATING STORAGE AND OFFLOADING VESSEL (FSO) FSO is a vessel used to store oil without processing it. Oil is pumped to FSO from production platform or FPSO by local small subsea pipeline. FSOs are fixed in position by anchors or they can be connected to a turret. FSOs are frequently converted from tankers. The yard’s work scope includes refurbishment and life extension works, accommodation upgrading, installation of new machinery, mooring structures and a helideck. Large FSOs are converted from very large crude carriers and have storage capacity of two million barrels of oil.

FSOS FSO Mayumba FSO Palanca

6. TRANSPORTATION TO SHORE SHUTTLE TANKER In the absence of a pipeline from the production facility to the shore terminal a shuttle tanker is needed to take over the oil cargo from production platforms, FPSO or FSO for transportation to the shore terminal. The ship is equipped with sophisticated off-loading equipment located at the bow that usually consists of a taut hawser arrangement. Shuttle tanker is maintained in position relative to the field or mother unit by DP, due to which it can receive oil from offshore units in heavy weather conditions.

SHUTTLE TANKER 1. Bow loading station, including temporary mooring arrangement to FPSO, 2. Cargo lines, 3. Helideck, 4. Accommodation

SHUTTLE TANKERS Shuttle tanker Windsor Knutsen Shuttle tanker Jorunn Knutsen

7. SUPPLY AND SERVICES SUPPLIERS AND ANCHOR HANDLERS Supply vessels are engaged in carrying fuel, fresh water and other provisions from shore to offshore installations. They often combine supply services with towing and anchor handling. Suppliers and anchor handlers are: Platform Supply Vessel (PSV) Fast Supply Vessel (FSV) Anchor Handling Tug (AHT) Anchor Handling Tug Supply vessel (AHTS) Towing Supply Vessel (TSV)

PLATFORM SUPPLY VESSEL (PSV) As the name suggests, PSVs are used to carry crew and supplies to the oil platform deep inside oceans, and bring cargo and personnel back to shore. The vessels transport a wide range of both liquid and dry (powder) cargo, such as fresh water, drilling fluids, mud, cement and fuel in internal storage tanks beneath the deck. The strengthened open deck is normally used to carry containers, drill pipes and other heavy equipment. During supply operations PSVs move by stern to the desired offshore installation to give easy access to delivered cargo.

PSV Other functions are fire-fighting and towing of floating units. For towing operations PSVs have a high bollard pull. They may also participate in anchor handling and render ROV services. Suppliers are characterized by superstructure and deckhouse at the foreship and a long flat aft deck - from 350 m² to 1, 000 m². They have no helideck and no cranes. The offshore platform uses its own cranes to lift cargo from deck. The difference from an AHT is that a PSV has a long aft deck and below-deck storage tanks. DP is used to maintain the ship in position.

BOURBON PSVS HOMERE, HEMERE AND HARMONIE These environmentally friendly diesel-electric vessels use less fuel than conventional direct drive propulsion vessels and produce far less pollution.

1. Working deck, 3. Steering gear, 4. Starboard ducted propeller, 6. Thruster, 9. Deck cranes, 12. Main engine, 14. Liferafts, 18. Bridge with controls for deck gear and ship manoeuvering, 20. Radar antennas, 21. Antenna for communication system / satellite antenna, 22. Switchboard, 25. Auxiliary generator

SUPPLIER NEAR A PRODUCTION PLATFORM

FAST SUPPLY VESSEL (FSV) Fast Supply Vessel (another name – Fast Support Intervention Vessel, or FSIV) differs from PSV only by size and seagoing speed. FSVs are designed to deliver smaller size cargo faster. They also serve for crew transfer and provide rapid assistance bringing intervention teams. Often FSVs are equipped with water jet main propulsion with maximum speed of 30 knots. They have over 240 m² in deck cargo space. Some of them may have DP class 1 or 2.

ANCHOR HANDLING TUG (AHT VESSEL) An AHT is used to set and retrieve anchors of moored offshore units – offshore rigs and work barges - and for towing these units. It often looks similar to a PSV, but has a shorter aft deck, an open stern roll and large winches to be able to pull anchors onto the deck. An AHT is equipped with one or two hydraulic cranes for handling cargo. It is additionally built for maritime fire-fighting and salvage.

AHT VESSEL This Seacor 5000 HP anchor handling tug was built in 1974 and fully rebuilt in 2002. Her general particulars are the following: LOA: 42, 42 m Breadth: 11, 14 m Depth: 5, 55 m Draft: 4, 65 m Displacement: 1104, 5 T DWT: 323, 5 T GRT: 600, 00 tons NRT: 180, 00 tons Capacity of her hydraulic crane is 3, 0 tons.

TOWING SUPPLY VESSEL (TSV) A TSV has the capacities to function as PSV vessels for servicing offshore drilling, production and construction operations. The winches and stern rollers give the vessel the ability to tow or assist with jack-up rig moves, to set ‘back-down” systems, and to install anchor buoys or navigational buoys. A TSV can also provide unique assistance to numerous other special projects that require winch and towing operations.

TSV The buoy is on deck and the anchor under tension as it is wound up from the seabed.

ANCHOR HANDLING TUG SUPPLY VESSEL (AHTS) AHTS vessels are mainly built to handle anchors for oil rigs and other anchored offshore units, tow them to location, anchor them up and, in a few cases, serve as Emergency Rescue Response vessels (ERRV). These vessels are fitted with winches for towing and anchor handling, have an open stern to allow the decking of anchors. They also have arrangements for quick anchor release which is operable from the bridge or other normally manned location in direct communication with the bridge. Because of wide deck space, AHTS vessels are often used for transfer of different cargo. In some cases, additional equipment may be mounted for offshore work purposes, like diving equipment, ROV shack, etc.

1. Working deck, 2. Anchor roller, 3. Steering gear, 4. Starboard ducted propeller, 5. Stern tube, 6. Thruster, 8. Tanks for dry bulk cargo (e. g. cement / mud), 9. Deck cranes, 10. Propeller shaft, 11. Reduction gear box, 12. Main engine, 14. Liferafts, 15. MOB boat with crane, 17. Storage reel for steel wires for anchor handling, 18. Bridge with controls for deck gear and ship’s manoeuvering, 19. Fire-fighting monitor, 22. Switchboard

AHTS Normand Master, built in Ulstein shipyard (Norway) in 2003, has large capacities combined with good maneuverability and can be fitted with a 250 -ton A-frame. LOA - 82, 1 m, Deck – 600 m², BHP – 23, 330

FAST CREW BOAT This vessel is used to change crew for drilling rigs or other craft in benign waters. Fast crew boats have aluminium or steel hulls; they are 10 -50 meters in length, with an accommodation for 30 -150 passengers in chairs. There is an open aft deck to take provisions, spares, repair equipment, lubricating materials, etc. An open deck provides sufficient space to embark/ disembark the crewmembers using a crew basket, suspended from the crane of the rig/ship. Some fast crew boats are equipped with DP, class 1 or 2.

Fast crew boats may develop the speed of over 35 knots. The crew is normally 6 -8 people.

8. MAINTENANCE AND REPAIR MULTIPURPOSE SUPPORT VESSEL (MSV) MSVs are made to meet the requirements of a versatile offshore market. They are specialized vessels used during field development where skills in multiple tasks are required. They are basically able to carry two or more functions without any modification. Very often MSVs afford some exact kind of offshore function on a permanent basis, but can be rapidly adapted for different types of mission: subsea construction and installation, inspection, maintenance and repair, laying cables, hoses or smalldiameter pipes, accommodation.

v MSVs typically have a relatively large accommodation, a flat work deck aft, a helideck, (heave-compensated) crane(s) and/or an Aframe aft and moonpools for controlled lowering of ROVs or other equipment. They often have facilities for divers and can work as DSV.

1. Working deck, 3. Steering gear, 6. Thruster, 7. Azimuth thruster, 9. Deck cranes, 12. Main engine, 13. Heavy lift crane, 14. Life rafts, 15. MOB boat with crane 16. Lifeboat, 18. Bridge with controls for deck gear and ship’s manoeuvering, 20. Radar antennas, 21. Antenna for communication system / satellite antenna, 22. Switchboard, 23. Anchor windlass, 24. Helideck.

MSVs carry large sophisticated equipment and accommodate a large number of personnel and are generally used as floating platforms for the operations carried out by subsea service providers.

CONSTRUCTION SUPPORT VESSEL (CSV) CSVs support complex offshore construction and installation, provide maintenance and repair. CSVs are significantly larger and more specialized than other offshore vessels. v They install or remove underwater structures on the oil and gas field – parts of platforms or full-sized platforms, risers, well-heads, christmas trees, flowlines, pumps, valves, etc. v. They offer state-of-the-art maritime construction equipment and computer cutting technology in a controlled environment. v

DIVING SUPPORT VESSEL (DSV) The advent of DSVs dates from the 60 -70 s of the preceding century, when the need arose for diving operations to be performed below and around oil production platforms in the North Sea and the Gulf of Mexico. A DSV is designed as a floating base for professional diving projects. At this time, divers can be lowered to depths up to 400 m. A DSV can provide the operations of eight divers at a time. Divers do inspections or repairs of subsea structures. They can use air for working depths less than 50 m. For depths below 50 m, saturation diving system is used.

DSV Saturation diving system provides a mixture of helium and oxygen (heliox) to eliminate the narcotic effect of nitrogen under pressure. The use of helium instead of nitrogen protects divers from caisson disease. Saturation system is installed on board and the bell is secured on top. The bell can be lowered out of the vessel’s board or through the moonpool by cables from a ship crane. Diving bell transports the divers between the saturation system and the work site. It is used as an underwater rescue vessel by working divers. It’s ballasted so as to remain upright in the water and to be negatively buoyant so that it sinks even when completely full of air.

DSV Along with saturation system and diving bells, DSVs are equipped with diving chambers. This is a simple form of a submersible vessel to take divers underwater and provide a temporary base and retrieval system in the depth. Protection and stable position of diving chambers are vital, so they are normally located with the divers’ living quarters in the area along the fore and aft line of the ship. To ensure safe diving operations, DSVs also have decompression chambers. These allow divers to complete their decompression stops at the end of a dive on the surface rather than underwater. This eliminates the risk of long decompressions underwater or dangerous conditions.

Divers are lowered through a moonpool which is a hole in the middle of the ship also allowing vertical transport of diving equipment.

An important design feature of diving support vessels is availability of a helideck, casualty evacuation or medical personnel delivery facilities. Most DSVs are fitted with ROV system used when submerging divers to detect potential hazards to their health and lives. v v

DSVs are anchor moored or dynamically positioned. When working with divers, very strict requirements apply to the anchor mooring or DP system, as a drift-off of the vessel could put the divers in danger. Therefore DSVs have to comply with the highest DP standard – class 3.

A hybrid of multipurpose construction vessel and diving support vessel

Diving support vessel near a work accommodation barge

ROV SUPPORT VESSEL (ROV SV) A ROV SV is a vessel from which ROV operations are conducted. ROV is unoccupied, highly maneuverable and operated by a person aboard a vessel machine. Usually the ROV is connected by an umbilical cord (a cable for power and controls) to the support vessel. ROV can be stowed on deck or inside special ROV-hangers. ROV tasks range from simple inspection of subsea structures, pipelines and platforms to connecting pipelines and placing underwater manifolds. They are used extensively both in the initial construction of a subsea development and the subsequent repair and maintenance.

ROV SV This subsea tool is the Remotely Operated Vehicle (ROV), a selfpropelled underwater remote controlled robot for pipe-laying/ route surveys, geo-technical surveys and inspection or construction and repair work made on offshore installations. ROV support vessel may provide the launch of up to five such vehicles.

ROV support vessels are equipped with computer-controlled, precision, position-keeping capabilities with added redundancy features, such as multiple computers, thrusters and reference systems. They have additional cabins, messroom facilities and client offices to comfortably accommodate the client ROV support crews.

ROV SVs are outfitted with a permanently installed active heavecompensated crane, and/or an A-frame crane, a helideck and DP system, generally class 2.

ROV support vessel with a heave-compensated crane

JACK-UP DP MAINTENANCE PLATFORM The barge (or platform) can be lifted above the surface and out of reach of the waves, when brought to its working position at DP. It can be used for maintenance of permanent oil platforms. The jackup platform also participates in installation of windfarms.

9. WATCH KEEPING STANDBY- AND CHASE VESSELS Standby vessels stay in the neighbourhood of platforms or offshore activities to perform rescue operations in case of emergency. Chase vessels are used to chase wandering ships away from platforms, offshore operations or seismic survey vessels.

STANDBY- AND CHASE VESSELS They are used as safety vessels for quick evacuation.

Maintenance jack-up near a production platform. Supplier and a chase vessel are near by.