Extended Operational and Trade Vocabulary

Marine Spatial Planning, Subsea Cables and Submarine Pipelines glossary

The subsea-infrastructure vocabulary: named submarine cable systems (AAE-1), HVDC cable technology, abandonment-and-recovery and aboveground pipelay installation methods, cable burial and protection, and the marine spatial planning terms that allocate seabed use. Grounds each term in the cable or pipeline installation operation it belongs to.

613 defined terms.

Showing 250 on this page (page 1 of 3).

A

A2 (cable system): Planned subsea cable system linking Asian markets, named in industry roadmaps as part of regional diversification away from South China Sea routes.
AAE-1 (Asia-Africa-Europe-1): Approximately 25,000 km submarine cable system connecting Hong Kong to Marseille via Southeast Asia, the Middle East, and the Mediterranean, in service since 2017.
Abandonment and Recovery (A&R): Pipelay operation in which the pipeline end is sealed, lowered to the seabed on a wire, and later recovered to resume laying after weather or repair.
ABB HVDC Light: Voltage-source converter HVDC technology developed by ABB (now Hitachi Energy), widely used in submarine power cable interconnectors.
Aboveground Installation (ABI): Subsea cable installation method in which the cable rests on the seabed surface, typically protected by rock berm or articulated pipe.
AC Submarine Cable: Alternating-current submarine power cable used for shorter offshore wind export links, generally below about 80 km due to charging current losses.
Active Heave Compensation: Crane/winch system that counters vessel heave in real time using hydraulics.
Adriatic LNG Terminal: Offshore gravity-based LNG regasification terminal off Porto Levante, Italy, connected to the national grid by a submarine pipeline.
Africa-1: Submarine cable system planned to link East and North Africa with Europe and the Middle East along the African coast.
AIS (Automatic Identification System) Exclusion: Use of AIS data in marine spatial planning to identify shipping density and define cable and pipeline corridors with reduced conflict.
Alcatel Submarine Networks (ASN): French submarine cable manufacturer and installer headquartered in Nozay, supplying systems including 2Africa, MAREA, and Dunant.
Allseas Group: Swiss-Dutch offshore contractor specializing in pipelay, heavy lift, and subsea construction, owner of Solitaire, Audacia, Lorelay, and Pioneering Spirit.
Amitié (cable system): Transatlantic submarine cable linking Lynn (Massachusetts), Le Porge (France), and Bude (UK), commissioned in 2023.
Ampere (cable system): Planned high-capacity submarine cable connecting Bilbao, Spain to the United States East Coast, announced by Google in 2024.
Anchor Drop Test: Trial in which an anchor is intentionally dropped on a cable protection system to verify impact resistance during cable engineering qualification.
Anchor Strike: Mechanical damage to a submarine cable or pipeline caused by a vessel anchor, a leading cause of subsea cable faults worldwide.
Annular Space: Insulated void between primary and secondary barriers in membrane containment, monitored for nitrogen purity and pressure.
Apricot Cable System: Subsea cable announced in 2021 connecting Japan, Taiwan, Guam, the Philippines, Indonesia, and Singapore, backed by Meta and Google.
APX-East and APX-West: Asia Pacific Cable Network East and West, older regional cable assets retired or upgraded into newer systems.
Aqualink: Proposed HVDC interconnector concept linking offshore wind clusters in the North Sea, studied under the European meshed-grid initiatives.
Arctic Connect: Cancelled subsea cable concept that would have linked Europe to Asia via the Northern Sea Route along the Russian Arctic coast.
Areas to be Avoided (ATBA): IMO ships' routeing measure under SOLAS V/10; used for the Aleutian Islands and Bering Strait.
Armored Cable: Submarine cable with one or more layers of galvanized steel wire armor providing mechanical protection in shallow or trawled waters.
Articulated Pipe: Series of interlocking cast-iron or polymer half-shells installed around a cable at landfalls and crossings to provide abrasion and impact protection.
Asgard Transport System: Norwegian gas pipeline from the Åsgard field complex in the Norwegian Sea to the Kårstø processing plant.
ASN North Highland Works: Greenock-area facility in Scotland that manufactures and tests submarine cable systems for Alcatel Submarine Networks.
Atlantic Crossing-1 (AC-1): 1998 transatlantic submarine cable system between New York, Germany, the Netherlands, and the UK, operated by Global Crossing.
Atlantic Crossing-2 (AC-2): Transatlantic cable completed in 2001 linking Brookhaven, New York, with Whitesands Bay, UK, expanding Global Crossing capacity.
Audacia: Allseas pipelay vessel of about 225 m length, designed for medium to large-diameter S-lay in water depths to roughly 3,500 m.
Australia Singapore Cable (ASC): 4,600 km submarine cable connecting Perth, Christmas Island, Jakarta, and Singapore, operated by SubPartners and Vocus.
Autonomous Underwater Vehicle (AUV) Survey: Pre-lay seabed mapping conducted by AUVs equipped with multibeam, sidescan sonar, and sub-bottom profilers for cable and pipeline routing.

B

Baltic Connector: 77 km natural gas pipeline between Inkoo, Finland, and Paldiski, Estonia, damaged by an anchor in October 2023 and repaired in 2024.
Baltic Pipe: Gas pipeline system from the Norwegian North Sea via Denmark to Poland, in service since 2022.
Baltic Sea Maritime Spatial Planning: Cross-border MSP coordinated by HELCOM-VASAB, the first sea basin to implement coherent national MSP plans under the EU MSP Directive.
Barents Observer Cable Incident 2021: Severing of the LoVe Ocean observatory subsea cable off Vesterålen, Norway, attributed to trawl-related damage.
Basslink: 290 km HVDC submarine power cable between Loy Yang, Victoria, and George Town, Tasmania, rated 500 MW and energized in 2006.
BatCable: Battery-storage and HVDC subsea link concept studied for the Iberian and North African corridor.
Bay-to-Bay (BtB): Subsea cable announced by Meta linking the United States West Coast directly to other points along the Pacific Rim.
Beach Manhole (BMH): Onshore vault at a cable landing site where the submarine cable transitions to the terrestrial backhaul cable.
Bend Restrictor: Polymer or steel device fitted to flexible risers and umbilicals to limit local curvature and prevent overbending during installation and service.
Bend Stiffener: Tapered polyurethane structure at the top of flexible flowlines and umbilicals that controls dynamic curvature at the hangoff.
BIFROST Cable System: 15,000 km submarine cable linking Singapore, Indonesia, Guam, and the United States, backed by Meta, Keppel, and Telin.
Bilateral Skidding System: Pipelay deck arrangement that moves stalks sideways for double-jointing on S-lay vessels such as Solitaire.
Biotop Cable: Bio-degradable mooring and cable concept studied in European environmental research projects for low-impact moorings.
Bird Caging: Defect mode in armored submarine cables where wires bulge outward, often after compression or torsion during recovery.
Block Valve Station: Above-ground or subsea facility on a pipeline allowing isolation of a segment for maintenance or emergency shutdown.
Blue Stream: 1,213 km natural gas pipeline across the Black Sea from Russia to Turkey, commissioned in 2003.
BOEM (Bureau of Ocean Energy Management): US Department of the Interior agency managing offshore energy and mineral leasing on the Outer Continental Shelf.
Bonny Express: Pipeline-laying vessel operated by Saipem, used in the Caspian and Mediterranean for medium-diameter S-lay work.
Boskalis Subsea Cables: Cable-installation arm of Royal Boskalis Westminster providing inter-array and export cable installation for offshore wind projects.
Boundary Mud Line: Reference plane in pipeline engineering corresponding to the original seabed level, used to define on-bottom stability calculations.
Bremerhaven O&M Cluster: Concentration of offshore wind operations and maintenance bases on Germany's North Sea coast, integral to regional MSP zoning.
Brent System Pipeline: Network of pipelines from the Brent and adjacent fields in the UK North Sea, including the Brent oil and FLAGS gas systems.
British Telecom Marine: Former cableship operating arm of BT, succeeded by Global Marine Systems in 1999.
Buchan Field Pipeline: Subsea infrastructure serving the Buchan and Hannay oil fields in the UK Central North Sea.
Bundle (pipeline bundle): Assembly of multiple flowlines, control lines, and umbilicals housed in a carrier pipe, towed to site by controlled-depth or off-bottom tow.
Burial Assessment Survey (BAS): Pre-installation geophysical study assessing seabed soil suitability for cable trenching or jetting.
Burial Protection Index (BPI): Index used by submarine cable operators to define burial depth requirements based on water depth and seabed activity.
Buried Cable Detection: Use of magnetometers, gradiometers, or active toning to locate buried cables for inspection, repair, or out-of-service recovery.
Bypass Pigging: Pipeline pigging operation using a tool with controlled bypass flow to manage debris or wax accumulations without flow shutdown.

C

C-Lion1: 1,173 km submarine telecommunications cable between Helsinki, Finland, and Rostock, Germany, in service since 2016 and damaged in 2024.
Cable Burial Risk Assessment (CBRA): Industry-standard methodology developed by Carbon Trust to determine economic burial depth for offshore wind export and inter-array cables.
Cable Compound: Onshore facility where submarine cables are manufactured in long continuous lengths and loaded onto cableships via shore turntables.
Cable Crossing Agreement: Contract between owners of two subsea cables or a cable and pipeline defining mutual obligations at a crossing point.
Cable Drum Carousel: Large turntable on a cableship that holds and pays out submarine cable during installation.
Cable Engine: Linear or wheel-based machine on a cableship that grips the cable and provides tension control during lay and recovery.
Cable Fault Locator (CFL): Test instrument that injects pulses into a submarine cable and uses time-domain reflectometry to estimate the distance to a fault.
Cable Innovator (CS): Global Marine cableship in service since 1995, one of the largest cableships ever built at 145 m length.
Cable Laying Vessel (CLV): Specialized ship configured for installation and repair of submarine power and telecommunications cables.
Cable Protection System (CPS): Conical polyurethane or interlocking pipe structure installed at the foundation of an offshore wind turbine to protect the inter-array cable.
Cable Protection Zone (CPZ): Statutory area, such as those gazetted under New Zealand's Submarine Cables and Pipelines Protection Act 1996, where fishing and anchoring are restricted.
Cable Repair Agreement (CRA): Long-term contract under which a consortium of cable owners shares the cost of a dedicated repair cableship in a region.
Cable Route Survey: Geophysical and geotechnical survey along a proposed submarine cable corridor, conducted with multibeam, sidescan, and sub-bottom profiling.
Cable Ship Reliance: ATL former cableship now operated by Global Marine, based in Portland, UK, primarily for North Atlantic maintenance.
Cable Wave: Slack management technique during laying in which the cable is intentionally laid with a small lateral excess to absorb seabed irregularities.
California Coastal Sanctuary: State-designated zone prohibiting new offshore oil and gas leasing within California's three-mile state waters.
Calypso Pipeline: Planned natural gas pipeline between Cyprus, Greece, and Italy, also referred to as the EastMed Pipeline project.
Cantarell Field Trunkline: Pipeline system in the Bay of Campeche, Mexico, serving the Cantarell oil complex operated by Pemex.
Carbon Capture and Storage Pipeline: Subsea pipeline transporting compressed CO2 to offshore geological storage, examples include the Northern Lights project in Norway.
Carbon Trust Offshore Wind Accelerator (OWA): Industry consortium that publishes guidance documents on cable protection, including CBRA and dynamic cable design.
Casing Spacer: Polymer or steel device that centralizes a carrier pipe within an outer pipe in pipe-in-pipe systems.
Castoro Otto: Saipem monohull pipelay vessel of about 162 m length used in shallow to medium water depths in the Mediterranean and Caspian.
Castoro Sei: Saipem semi-submersible pipelay vessel commissioned in 1978, used on Blue Stream, Nord Stream, and other large-diameter projects.
Catenary Riser: Hanging configuration of a flexible or rigid riser connecting a floating production unit to a subsea pipeline.
Cathodic Protection: Sacrificial or impressed current system protecting subsea steel from corrosion.
Cellular Concrete Mattress: Pre-cast concrete block mat placed over cables and pipelines for crossing or impact protection.
Cementing the Stinger: Use of jacket concrete weight coating on a stinger during S-lay operations on Castoro Sei to control pipe stress.
Center for International Maritime Security (CIMSEC): Independent forum publishing analyses on subsea cable resilience and maritime security policy.
Channel Islands Cable System (CIS): Older intra-British Isles submarine cable network serving Jersey, Guernsey, and the UK mainland.
Charles Darwin Foundation: Galápagos research and conservation body whose data underpins MSP for the Galápagos Marine Reserve.
China Telecom Global Marine: Cable installation and maintenance subsidiary headquartered in Shanghai, operating cableships including Fu Hai and Fu An.
Christchurch Bay Cable Incident: Repeated trawl damage to telecommunications cables in the English Channel, illustrating cable-fisheries conflict.
Christmas Island Cable Landing: Strategic landing point in the Indian Ocean used by ASC and other cable systems linking Australia to Singapore.
CIGRE TB 490: International Council on Large Electric Systems technical brochure on recommendations for testing of long AC submarine cables with extruded insulation.
Circuit Continuity Test (CCT): Electrical verification of submarine power cable conductor continuity prior to commissioning.
Clean Energy Wire Cluster Wind: Multi-government initiative to coordinate North Sea offshore wind buildout with submarine grid interconnection.
Clean Path New York: Proposed subsea-and-overland HVDC line bringing upstate wind and solar energy to New York City.
Coastal Zone Management Act (CZMA): US federal statute enabling state coastal management programs that influence offshore cable and pipeline siting.
Cofferdam Landing: Cable or pipeline landfall constructed inside a sheet-piled enclosure to protect shore operations from wave and tide action.
Cold Bend: Maximum allowable curvature for a cable or pipe at low temperatures, defined by manufacturer storage and installation specifications.
COLREGS Compliance Zone: Buffer region around cable-laying operations within which third-party vessels must maintain clearance under collision regulations.
Continental Shelf Act (UK): 1964 UK statute establishing jurisdiction over the seabed and subsoil of the UK Continental Shelf, governing pipelines and cables.
Contractor Pre-Lay Survey (CPS): Survey performed by the cable contractor before installation to verify route conditions established during the desktop study.
Convention for the Protection of Submarine Cables (1884): Multilateral treaty signed in Paris, the foundational instrument for the international law of submarine cables.
Cook Strait Cable: HVDC submarine power link between New Zealand's North and South Islands operated by Transpower, originally commissioned in 1965 as Pole 1.
Coral HVDC Project: Proposed subsea power interconnector linking the Adriatic with Italian and Balkan grids.
Corrosion Coating: Three-layer polyethylene or fusion-bonded epoxy coating applied to subsea pipelines to prevent external corrosion.
CSC Construction: Cable-ship company operating specialized pipe-laying and cable-laying barges in Asia-Pacific subsea projects.
CSCT Pendant: Cable seabed termination assembly used at offshore platforms and substations for cable hangoff.
Cuttings Pile: Mound of drilling waste on the seabed near a former wellsite, an MSP constraint for cable and pipeline routing.

D

Dahlia Field Pipeline: Subsea export pipeline serving the Dahlia field in Block 17 offshore Angola.
Dansk Undergrunds Consortium (DUC): Operator group of Denmark's North Sea hydrocarbon assets, including the Tyra gas hub and associated pipelines.
Datum Mismatch: Cable burial reporting issue arising when survey datums (WGS84 vs ED50) are not harmonized between baseline and as-laid surveys.
De Beers Marine: South African operator of subsea mining vessels off Namibia, with seabed activities coordinated with MSP for cable routes.
Deep-water S-lay: Pipelay configuration using a long stinger and elevated tension to install pipelines in water depths beyond 1,500 m.
Deepsea Worker: Multi-purpose subsea support vessel formerly used by Subsea 7, configured for IRM and cable maintenance.
DeepStar Joint Industry Project: US Gulf of Mexico research consortium addressing deepwater pipeline, riser, and flow-assurance challenges.
DEME Group: Belgian dredging and offshore contractor whose subsea cable arm DEME Offshore installs inter-array and export cables.
DenGyo: Japanese contractor active in cable landing civil works around East Asia.
Desktop Study: First stage of submarine cable and pipeline route engineering, compiling charts, historical surveys, and environmental data.
Det Norske Veritas (DNV): Norwegian classification society publishing standards for subsea pipelines (DNV-ST-F101) and submarine cables (DNV-RP-0360).
Dianna Cable Crossing: Notional crossing example used in industry training for cable-pipeline interaction analysis.
Differential settlement: uneven subsidence of quay foundations.
Direct Burial Cable: Subsea cable designed for installation without conduit, relying on armor and burial for protection.
Disturbance Footprint: MSP metric quantifying the seabed area temporarily or permanently altered by cable and pipeline installation.
Diving Support Vessel (DSV): Vessel with saturation-diving capability.
DOF Subsea: Norwegian subsea services contractor operating ROV-equipped vessels for cable and pipeline inspection, repair, and maintenance.
Doggerbank Wind Farms: Cluster of UK offshore wind projects in the North Sea connected by HVDC export cables to Yorkshire landfalls.
Dolwin Alpha: HVDC offshore converter platform in the German Bight collecting power from the DolWin1 cluster.
Double-Joint: Practice of welding two 12 m pipe joints into a 24 m double joint to increase laying speed on S-lay vessels.
Drag Embedment Anchor: Traditional fluke anchor embedding by horizontal pull.
Drone Inspection: Use of unmanned surface vehicles and AUVs to inspect pipeline corridors and cable landfalls without dedicated DSVs.
Dual Caterpillar Tensioner: Pipelay device with two parallel caterpillar tracks providing controlled pulling force on the pipeline.
Dunant (cable system): 6,400 km transatlantic cable from Virginia Beach to Saint-Hilaire-de-Riez, France, the first Google private cable using 12 fiber pairs at 250 Tbps.
Dynamic Cable: Submarine cable used on floating offshore structures designed to withstand cyclic loading from wave and current motion.
Dynamic Positioning Class 2 (DP2): Redundancy standard for cable-lay and pipelay vessels enabling station-keeping without a single point of failure.

E

East African Submarine Cable System (EASSy): 10,000 km submarine cable along the east coast of Africa, in service since 2010.
East Med Pipeline: Proposed 1,900 km natural gas pipeline from Israeli and Cypriot fields to Greece and Italy, under feasibility study.
East Spar Pipeline: Subsea gas pipeline serving the East Spar field offshore Western Australia.
EastWind: Concept HVDC interconnector linking offshore wind clusters in the Baltic Sea.
Echo Cable System: Subsea cable linking Singapore, Indonesia, Guam, and the United States, the first Google cable to directly connect Singapore to North America.
EELink: HVDC interconnector concept proposed between Estonia and Latvia to reinforce Baltic grid integration.
EGL1 (East Green Link 1): 2 GW HVDC submarine cable between Torness, Scotland, and Hawthorn Pit, England, under development by SP Energy Networks and National Grid.
EGL2 (East Green Link 2): 2 GW HVDC subsea link between Peterhead, Scotland, and Drax, England, planned for energization later in the 2020s.
EllaLink: 6,200 km submarine cable connecting Sines, Portugal, with Fortaleza, Brazil, in service since 2021.
EMC Cable: Electromagnetic compatibility-screened cable used for sensitive inter-array cabling at certain offshore wind sites.
Emerald Bridge: Proposed subsea power link concept between Ireland and continental Europe.
Endurance Field: Carbon storage site in the UK Southern North Sea, target of the East Coast Cluster CO2 pipeline.
Energinet: Danish transmission system operator and partner in submarine HVDC interconnectors including Kontek, Skagerrak, and COBRAcable.
Environmental Impact Assessment EIA: Assessment required before the establishment or expansion of a recycling yard.
Environmental Protection Authority (EPA) NZ: Regulator for activities in New Zealand's EEZ including cable and pipeline consents.
Epoxy Coating: Fusion-bonded epoxy applied to pipeline field joints and external surfaces for corrosion protection.
Equinor: Norwegian operator and partner in the Northern Lights CO2 storage project.
Espoo Convention: 1991 UN treaty on environmental impact assessment in a transboundary context, applied to cross-border submarine cables and pipelines.
European Marine Observation and Data Network (EMODnet): EU portal providing bathymetric, geological, and human-activity data for MSP and cable routing.
European Subsea Cables Association (ESCA): Trade body promoting safe installation and operation of subsea telecommunications and power cables in European waters.
Europipe I: 660 km submarine gas pipeline from Draupner to Dornum, Germany, commissioned in 1995.
Europipe II: 658 km submarine gas pipeline from Kårstø to Dornum, in service since 1999.
Excess Cable: Length of cable laid in excess of the seabed distance, typically 1 to 3 percent, to accommodate route irregularities.
Export Cable: High-voltage submarine cable carrying power from an offshore substation to the onshore grid connection point.
External Aggression Index: Composite risk metric used in cable and pipeline routing combining trawling intensity, anchoring frequency, and shipping density.

F

Fab1 Pipelay Vessel: Heavy-lift and pipelay barge operated by McDermott in the Middle East and Caspian.
FALCON 2: Refresh project for cable infrastructure in the Persian Gulf and Indian Ocean.
Falcon Cable System: 11,800 km submarine cable in the Persian Gulf, Red Sea, and India, operated by Global Cloud Xchange.
Fanwave: Concept for a Pacific submarine cable mesh focusing on resilience between US territories.
Far North Fiber: Proposed transarctic submarine cable connecting Europe, Asia, and North America via the Northwest Passage and Northern Sea Route.
Fault Section Replacement: Submarine cable repair method in which a damaged section is cut out and a new piece is jointed in using two final splices.
FCC Submarine Cable Landing Licence: License required under the 1921 Cable Landing License Act before a submarine cable can land on US territory.
Federal Energy Regulatory Commission (FERC): US agency regulating interstate pipeline tariffs, including subsea segments of natural gas systems.
FibreSpan: Aerial-bundle cable design adapted for short submerged crossings in certain inland and estuarine projects.
Field Joint Coating (FJC): On-vessel coating applied at each girth weld during pipelay to restore corrosion protection between the factory-coated pipe ends.
Final Splice: Operation in which the last segment of a repaired or newly installed submarine cable is jointed and laid down to the seabed.
Finnpilot Pilotage: Finnish pilotage authority providing data used in Baltic MSP for cable and pipeline corridors.
First Generation J-lay Tower: Vertical pipelay tower system as installed on vessels such as DCV Balder for deepwater rigid pipelines.
Flag of Convenience Cableship: Cable installation vessel registered under an open registry to gain operational flexibility in cross-border deployments.
Flag-State Notification: Diplomatic procedure under UNCLOS by which cable repair vessels notify coastal states before operating in their EEZ.
FLAGS (Far North Liquids and Associated Gas System): UK pipeline from Brent to St Fergus carrying natural gas and condensate from the northern North Sea.
Flex-Lay: Installation method for flexible flowlines and umbilicals using vertical lay systems and reel carousels.
Flexible Flowline: Multi-layer unbonded pipeline used for short tie-ins between subsea wells and host facilities.
Floating Production Storage and Offloading (FPSO) Riser Tower: Vertical bundle of risers connecting subsea pipelines and umbilicals to an FPSO turret.
Flow Assurance: Engineering discipline managing hydrate, wax, asphaltene, and slugging risk in subsea oil and gas pipelines.
Forewind: Original developer consortium for the Dogger Bank offshore wind zone, dissolved in 2015 after zone partitioning.
France-Alderney-Britain Link (FAB Link): Proposed 1.4 GW HVDC interconnector between France and Britain via Alderney, with planning paused.
Free Span: Section of pipeline suspended above the seabed where it is unsupported, monitored for vortex-induced vibration.
Friction Bend: Pipelay parameter combining bending stress and friction at the seabed touchdown during S-lay installation.
Fronts End Engineering Design (FEED): Front-end engineering and design phase that produces detailed cable or pipeline specifications before procurement.
Fu An: Cable ship operated by SBSS, based in Shanghai, providing maintenance in the East Asia region.
Fu Hai: Cable maintenance vessel of SBSS operating in the China Sea Cable Maintenance Agreement area.
Fugro: Dutch geo-data company providing site characterization, survey, and consultancy for subsea cables, pipelines, and offshore wind foundations.
Furuholmen Substation: HVAC offshore substation supporting Nordic offshore wind grid expansion.

G

Galápagos Marine Reserve: 198,000 km2 protected area off Ecuador subject to strict spatial planning that restricts subsea cable and pipeline routing.
Gas Pipeline Tribunal: Independent body in Australia that adjudicates access disputes on covered offshore pipelines.
GASCO: Abu Dhabi National Oil Company subsidiary operating subsea and onshore gas pipelines in the UAE.
Gassco: Norwegian operator of the integrated gas transport system from the Norwegian shelf to continental Europe.
Gaz-System: Polish gas transmission operator and owner of the Baltic Pipe's Polish offshore segment.
General Bathymetric Chart of the Oceans (GEBCO): Global bathymetric grid maintained jointly by IHO and IOC, foundational input for cable route engineering.
Geographic Information System (GIS) MSP Tool: Spatial-analysis platform used by planners to overlay marine activities, cables, and pipelines.
Geophysical Mobile Survey Set: Multibeam, sub-bottom profiler, sidescan sonar, and magnetometer suite deployed on cable and pipeline route surveys.
GHESQUIERE Marine Spatial Plan: Belgian federal MSP for the North Sea covering the period 2020-2026, defining cable corridors and wind zones.
Global Cloud Xchange (GCX): Operator of the FA-1 and FLAG cable systems across the Indian Ocean and Middle East.
Global Marine Group: UK headquartered subsea cable installation and maintenance company, operator of cableships including Cable Innovator and Sovereign.
Glomar Survey Vessel: Multi-purpose survey vessel of Glomar Offshore frequently chartered for cable route surveys in the North Sea.
GMSL Cable Innovator: See "Cable Innovator (CS)".
Gnatcatcher Cable Project: Industry-internal name for a regional Pacific cable upgrade.
GO-NSL (Greenlink Interconnector): 504 MW HVDC interconnector between Wexford, Ireland, and Pembrokeshire, Wales, energized in 2024.
Gondwana-1: 2,200 km submarine cable connecting New Caledonia to Sydney, in service since 2008.
GoNet Submarine Cable: Proposed submarine cable linking the Gulf of Mexico to Caribbean landing points.
Google Cloud Subsea Strategy: Investment program by Google in private submarine cables including Dunant, Equiano, and Curie.
Gravel Berm: Layer of graded gravel placed over a pipeline or cable for protection in trawled or anchoring areas.
Grease-Filled Cable Joint: Submarine cable joint type filled with hydrocarbon grease to prevent water ingress.
Great Lakes Submarine Power Cable: HVDC and HVAC links beneath the Great Lakes, including the New York to Vermont power link studied across Lake Champlain.
Greater Tortue Ahmeyim Pipeline: Subsea gas pipeline serving the BP-led LNG project on the Mauritania-Senegal maritime border.
Greenland Connect: 4,800 km submarine telecommunications cable linking Nuuk, Greenland, with Reykjavik, Iceland, and Newfoundland, in service since 2009.
Greenlink Interconnector: 504 MW HVDC submarine cable between Ireland and Wales, see GO-NSL.
Greensand project: Danish CO2 storage project in the depleted Nini oil field led by INEOS and Wintershall.
Grid Reinforcement Cable: Submarine cable installed to strengthen interconnection between regions of an existing electricity grid, often using HVAC.
Ground Avoidance Pipelay: Routing technique avoiding boulders, slopes, and free-span hotspots identified during the survey campaign.

H

Halifax Cable Landing: Major North Atlantic cable landing site in Nova Scotia hosting EXA, Hibernia Express, and Greenland Connect endings.
Hampton Roads Cable Landing: Virginia Beach landing serving MAREA, Dunant, and BRUSA cable systems.
Hawaiki Cable: 15,000 km submarine cable connecting Australia, New Zealand, American Samoa, Hawaii, and the US mainland, in service since 2018.
Heave Compensated Crane: Offshore crane on installation vessels that compensates for vessel motion when lowering cable accessories and pipeline structures.
HELCOM: Helsinki Commission protecting the Baltic Sea marine environment.
HelWin1: 576 MW HVDC link between the HelWin alpha offshore platform in the German Bight and the Büttel onshore station.
HelWin2: 690 MW HVDC link connecting HelWin beta to the Büttel onshore converter station.
Hi-Pot Test: High-potential dielectric test applied to submarine power cables after installation to verify insulation integrity.
Hibernia Express: 4,600 km low-latency transatlantic submarine cable from Halifax to Brean, UK, in service since 2015.
High Voltage Direct Current (HVDC) Submarine Cable: Bulk power transmission cable using direct current, preferred over HVAC for long submarine routes due to lower charging losses.
Hitachi Energy: Power technology supplier providing HVDC submarine cables and converter stations for projects including NordLink and North Sea Link.
HMC Aegir: Heerema Marine Contractors deepwater construction vessel capable of J-lay and reel-lay operations.
HMC Balder: Heerema semi-submersible crane vessel originally equipped with a J-lay tower for deepwater pipelay.
Hokkaido-Honshu HVDC: 600 MW submarine HVDC interconnector linking Hokkaido and Honshu islands in Japan.
Honshu-Shikoku HVDC: Japanese DC interconnector across the Kii Channel between Honshu and Shikoku islands.
Horizontal Directional Drilling (HDD): Trenchless landfall method drilling a borehole from shore to a wet exit beyond the surf zone to pull in cables or small pipelines.
Hornsea Wind Farms: UK offshore wind cluster off the Yorkshire coast with HVDC and HVAC export cables to Killingholme.
Houston-Galveston VTS Cable Crossing Procedure: Local protocol coordinating subsea cable repairs with pilot operations in the Houston Ship Channel.
Hub Beach Joint: Onshore manhole transition where a submarine cable is jointed to a terrestrial backhaul cable.
Hudson Canyon Pipeline Corridor: Routing study area off New York and New Jersey balancing pipelines, cables, and fisheries.
Hyaline Subsea Cable: Trade reference to ultra-low loss optical fiber cable designs used in modern transoceanic systems.
Hydrate Inhibition Line: Subsea line carrying methanol or MEG to flowlines for hydrate prevention in deepwater oil and gas systems.
HYPERSCALE Marine Spatial Plan: Workshop name used in EU MSP capacity building.

I

Ichthys Gas Export Pipeline: 889 km subsea gas pipeline from the Ichthys field to Bladin Point, Darwin, Australia.
IEC 60840: International standard for power cables with extruded insulation, 30 to 150 kV, applied to inter-array offshore wind cables.
IEC 63026: International standard covering subsea power cables for DC up to 320 kV.
In-Line Inspection (ILI): Use of intelligent pigs to assess pipeline wall thickness, geometry, and integrity from inside the line.
In-Service Inspection: Periodic survey of cables and pipelines after commissioning to detect exposures, free spans, or third-party damage.
In-Service Repair: Cable repair conducted on a live system using bypass cables and final splice procedures.
India Cable Landing Stations: Mumbai, Chennai, Kochi, and other coastal landings hosting systems including SEA-ME-WE, BBG, MIST, and 2Africa.
Indus West Pipeline: Subsea gas pipeline serving Pakistan's offshore exploration.
Inertial Navigation System (INS): Self-contained dead-reckoning system.
Inertization: Filling a pipeline with nitrogen to prevent corrosion or combustion during preservation periods.