Offshore Terms Dictionary

BOSIET

Basic Offshore Safety Induction and Emergency Training — the primary safety certificate required to work on oil and gas platforms. Issued by OPITO-accredited training centres, it covers helicopter underwater escape (HUET), CA-EBS breathing systems, sea survival, firefighting, and first aid. Required for platform access in the UK, Norway, and most international oil and gas regions. Valid for 4 years; renewed via FOET.

FOET

Further Offshore Emergency Training — the renewal course for BOSIET, completed every 4 years. Shorter than the initial BOSIET but retains all practical elements including the HUET pool session. Typically costs €400–€580. If a BOSIET has been expired for more than 6 months, some operators require a full BOSIET retake rather than FOET — always confirm with the operator before booking.

OPITO

Offshore Petroleum Industry Training Organisation — the industry body that sets and accredits safety training standards for the upstream oil and gas sector globally. OPITO-accredited certificates (BOSIET, FOET, MIST, HUET) are the recognised standard for platform access worldwide. Only training completed at an OPITO-accredited centre is accepted by offshore operators.

MIST

Minimum Industry Safety Training — a 1-day online safety induction course required by most UK offshore operators alongside BOSIET. Covers site-specific safety procedures, permit-to-work awareness, and hazard identification. Costs approximately €45–€70 and is valid for 2 years. It does not replace BOSIET — both are required for UK North Sea platform access.

STCW

Standards of Training, Certification and Watchkeeping for Seafarers — an international maritime convention established by the IMO that defines the minimum training and certification requirements for commercial vessel crews. Required for anyone working aboard vessels including crew transfer vessels, platform supply ships, and offshore support vessels. The STCW Basic Safety Training package covers personal survival, fire prevention, first aid, and personal safety.

HUET

Helicopter Underwater Escape Training — a practical pool exercise in which candidates practice escaping from a simulated helicopter fuselage after it ditches and inverts underwater. A mandatory component of BOSIET and FOET. Widely considered the most demanding element of offshore safety training. Instructors are present in the water throughout; the exercise is conducted at a controlled pace.

CA-EBS

Compressed Air Emergency Breathing System — a small personal breathing device worn on offshore helicopter flights. If the helicopter ditches and inverts underwater, the CA-EBS provides a short supply of breathable air to allow escape. Training to deploy and use it is included in BOSIET and FOET. Required on most offshore helicopter routes and sometimes sold as an add-on to BOSIET if not included in the base price.

OGUK

Offshore Energies UK (formerly Oil and Gas UK) — the trade association representing the UK's offshore energy industry. In the context of offshore careers, OGUK most commonly refers to the OGUK Offshore Medical standard: a health assessment covering cardiovascular fitness, vision, hearing, blood pressure, BMI, and blood and urine tests. The OGUK medical is required to work offshore in the UK and on many international projects. Valid for 2 years, with an annual review required from age 40.

PSV

Platform Supply Vessel — a type of offshore support vessel designed to carry cargo, equipment, fuel, water, and consumables between shore bases and offshore installations. PSVs form the primary logistics backbone of offshore oil and gas operations. They are classified as commercial vessels and their crews work under STCW maritime standards. Deck officer and engineer roles on PSVs require maritime qualifications.

AHTS

Anchor Handling Tug Supply vessel — a specialised offshore vessel designed to handle the mooring anchors of drilling rigs and floating platforms, provide towing services, and supply offshore installations. Anchor-handling operations are among the most hazardous in the marine industry due to the loads and dynamics involved. AHTS vessels are crewed under STCW maritime standards, with additional competency requirements for anchor-handling operations.

DSV

Dive Support Vessel — a specialist vessel that supports commercial diving and subsea intervention operations. DSVs carry saturation diving systems, ROVs, and hyperbaric rescue chambers, and operate as the surface platform for deep-water diving campaigns. Used for subsea pipeline inspection, repair, and construction work. Crew include marine officers, dive supervisors, saturation divers, and ROV personnel.

FPSO

Floating Production, Storage and Offloading vessel — an offshore facility that processes hydrocarbon fluids from subsea wells, stores the produced crude oil or gas, and periodically offloads it to shuttle tankers for export to shore. FPSOs are used in deepwater and remote locations where a pipeline to shore is not viable. They combine a full processing plant, large storage capacity, and a ship. Crews are large (often 200–400 personnel) and rotations are typically 28/28 or 4/4.

FLNG

Floating Liquefied Natural Gas facility — an offshore facility that produces, liquefies, stores, and offloads LNG directly at sea, eliminating the need for an onshore liquefaction plant. FLNG vessels are among the most complex and expensive offshore assets ever constructed. Shell's Prelude FLNG off northwestern Australia is the largest floating structure ever built. FLNG operations combine upstream production, cryogenic processing, and LNG export all on a single hull.

DP

Dynamic Positioning — an automated computer-controlled system that uses thrusters to keep a vessel at a precise position and heading without anchoring. Essential for drillships, DSVs, and construction vessels in deepwater where anchoring is not possible. DP class indicates the level of redundancy: DP1 (basic), DP2 (redundant systems), DP3 (full redundancy with physical separation). Higher DP class is required for more safety-critical operations.

DPO

Dynamic Positioning Operator — a specialist marine officer qualified to operate Dynamic Positioning systems on offshore vessels. DPOs are certified through programmes accredited by the Nautical Institute. Certification requires sea time on DP vessels logged in an official DP logbook, completion of simulator and induction courses, and a watchkeeping assessment. DPO certification is required to legally operate DP systems and is a valued qualification on offshore vessels.

ROV

Remotely Operated Vehicle — an underwater robot connected to a surface vessel or platform by a tether cable that carries power, control signals, and data. ROVs are used for visual inspection, survey, tooling operations, construction support, and emergency response on subsea infrastructure. They range from small observation-class vehicles for inspection to large work-class ROVs with hydraulic manipulator arms capable of operating valves and connecting subsea equipment.

NDT

Non-Destructive Testing — a range of inspection techniques used to assess the condition of materials, welds, and structures without causing damage. Common NDT methods include ultrasonic testing (UT), magnetic particle inspection (MPI), radiographic testing (RT), eddy current testing (ECT), and visual inspection. NDT technicians play a critical role in offshore asset integrity programmes, inspecting welds, pipework, and structural components. Qualifications are typically issued to PCN (CSWIP) standards.

IRATA

Industrial Rope Access Trade Association — the international body that sets standards for industrial rope access, a technique for accessing difficult structures using ropes, harnesses, and specialised rigging equipment. IRATA-certified technicians work on offshore platforms, wind turbines, bridges, and tall structures. IRATA has three levels: Technician (Level 1), Supervisor (Level 2), and Advanced Supervisor (Level 3). Level 3 requires a minimum of 1,000 logged rope access hours.

GWO

Global Wind Organisation — the trade organisation that sets safety training standards for the wind energy sector. The GWO Basic Safety Training (BST) package — covering manual handling, first aid, fire awareness, working at heights, and sea survival — is the primary safety requirement for offshore wind technicians, equivalent to BOSIET in the oil and gas sector. GWO certificates are valid for 2 years (shorter than BOSIET's 4-year validity).

LOLER

Lifting Operations and Lifting Equipment Regulations 1998 — UK legislation that sets legal requirements for the safe use, inspection, and maintenance of lifting equipment. Covers cranes, hoists, slings, shackles, spreader beams, and all other lifting accessories used extensively offshore. LOLER requires all lifting equipment to be thoroughly examined at defined intervals by a competent person, and all lifting operations to be properly planned and carried out by competent personnel.

PUWER

Provision and Use of Work Equipment Regulations 1998 — UK legislation requiring that all work equipment is suitable for its intended purpose, maintained in a safe condition, inspected at appropriate intervals, and used only by trained personnel. Applies to virtually all machinery, tools, and installed plant used offshore. PUWER overlaps with LOLER for lifting equipment and with COSHH for equipment handling hazardous substances.

COSHH

Control of Substances Hazardous to Health — UK regulations (2002) requiring employers to assess and control the risks from exposure to hazardous substances in the workplace. Offshore applications include drilling chemicals, mud additives, cleaning agents, biocides, and hydrocarbons. COSHH assessments form part of the permit-to-work documentation for tasks involving hazardous substances, specifying the substances present, exposure limits, and required PPE.

Permit to Work

A formal safety management system used offshore to authorise and control non-routine tasks that carry significant risk. Before work begins, a written permit is issued specifying the task, location, hazards, isolation requirements, required PPE, and authorised personnel. Common permit types include hot work permits (welding, grinding), confined space entry permits, and electrical isolation permits. PTW systems are central to offshore safety culture and are audited rigorously.

SIMOPS

Simultaneous Operations — the planned execution of two or more potentially conflicting operations at the same time on or near an offshore installation. Common examples include drilling while production is ongoing, crane operations during helicopter movements, or construction vessel work near a live platform. SIMOPS require detailed risk assessments, a SIMOPS matrix identifying incompatible activities, clear communication protocols, and a dedicated SIMOPS coordinator.

Jackup

A mobile offshore drilling unit (MODU) consisting of a buoyant hull fitted with extendable steel legs. When on location, the legs are lowered to the seabed and the hull is raised ('jacked up') above the water surface on hydraulic or rack-and-pinion systems. Jackups are self-elevating and suitable for water depths up to approximately 150 metres. They are the most common type of mobile drilling rig used in shallow-water regions including the North Sea, Gulf of Mexico, and Middle East.

Semi-Sub

Semi-submersible — an offshore drilling unit or production platform supported by large pontoons submerged below the water surface, connected to the main deck by vertical columns. The submerged pontoons reduce the vessel's response to surface wave action, making semi-submersibles more stable than ship-shaped hulls in harsh conditions. Semi-subs are suitable for deepwater drilling (up to 3,000+ metres) and are used in the North Sea, Gulf of Mexico, and West Africa. They can be moored or dynamically positioned.

Drillship

A ship-shaped vessel specially designed for deepwater and ultra-deepwater drilling, equipped with a drilling derrick mounted over a moonpool (a vertical opening through the hull). Drillships are self-propelled and typically dynamically positioned (DP2 or DP3), enabling them to operate in water depths exceeding 3,000 metres without anchoring. They offer greater mobility between locations than semi-submersibles but are more susceptible to vessel motion in rough seas.

SOV

Service Operations Vessel — a specialist vessel used in offshore wind operations to transport, accommodate, and support maintenance technicians for extended periods at sea. SOVs have motion-compensated gangways (walk-to-work systems) that allow safe personnel transfer to turbine platforms in wave heights up to 2.5–3 metres. Typically accommodating 60–120 technicians, SOVs have transformed the economics of offshore wind O&M by dramatically reducing weather downtime.

CTV

Crew Transfer Vessel — a fast, small catamaran used to transport maintenance technicians from port to offshore wind turbines and back on a daily basis. CTVs transfer personnel by pushing directly against the turbine access platform using fendering (bump-and-transfer method). They typically carry 12 technicians, operate at speeds of 25–35 knots, and work within 50–80 nautical miles of port. CTV deck crew require STCW Basic Safety Training and an ENG1 seafarers medical.

HSE

Health, Safety and Environment — in the offshore context, HSE refers both to the discipline of managing health, safety, and environmental risks on an installation, and to the UK Health and Safety Executive, the government regulator responsible for offshore safety in Great Britain. HSE officers offshore are responsible for permit-to-work oversight, safety audits, incident investigation, and safety training. The UK HSE also operates the Offshore Safety Directive and conducts inspections on UK Continental Shelf installations.