Loading…
The International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW) sets minimum competency standards for officers and ratings on internationally trading vessels. Its 2010 Manila Amendments brought the current framework — bridge/engine resource management, ECDIS, polar code, modern medical training — and a 2026 review adds mandatory bullying and harassment prevention. Each Certificate of Competency (CoC) is issued by a flag-state administration, recognised internationally under STCW Regulation I/10.
Certificates grouped by category below. Click any for prerequisites, hours, validity, refresher cadence, and typical cost.
STCW Reg. II/5 Able Seafarer Deck rating; AB equivalent under STCW 2010.
STCW Reg. III/5 Able Seafarer Engine rating; equivalent of motorman / oiler under STCW 2010.
STCW Reg. III/7 Electro-Technical Rating for engine-room electricians.
STCW Reg. III/4 RFPEW certificate for engine-room ratings keeping watch.
STCW Reg. II/4 RFPNW certificate for ratings keeping bridge lookouts.
European inland waterway dangerous goods training under ADN; basic, gas, chemical specialisation tracks.
European Inland Waterways navigation rules endorsement (Code Européen des Voies de la Navigation Intérieure); required for transit of EU inland waterways.
UK Boatmaster Licence Tier 1 for inland and limited estuarial passenger / cargo vessels.
Advanced training for officers responsible for chemical tanker cargo operations, building on basic chem familiarisation. Covers IBC Code, cargo segregation, MARPOL Annex II categorisation, tank cleaning, MARPOL prewash, ODMCS.
Advanced Fire-Fighting under STCW A-VI/3 — required of officers and any rating designated to control fire-fighting operations. Covers fire-prevention strategy, fire-fighting organisation, ventilation control, fixed installations (CO2, foam, sprinkler), command of fire teams, post-fire investigation. Practical refresher every five years.
Advanced training under IGC Code for LNG/LPG carrier cargo officers. Covers cargo containment systems, BOG management, ESD-1/2, custody transfer, gassing-up/cool-down, reliquefaction.
STCW Reg. V/1-1 advanced training for officers in charge of cargo operations on oil tankers, going beyond the basic familiarisation course. Covers cargo handling, ballast operations, gauging, ESD, ISGOTT compliance, vapour control, COW, IGS.
Advanced Training for Chemical Tanker Cargo Operations under STCW A-V/1-1-3 — required of officers with immediate cargo responsibility on a chemical tanker. Cargo compatibility, IBC Code, tank cleaning between cargoes, vapour and slops control, MARPOL Annex II compliance.
Advanced Training for Liquefied Gas Tanker Cargo Operations under STCW A-V/1-2-2 — required of officers with immediate cargo responsibility on a gas carrier. Cargo containment systems (membrane, MOSS, type C), cargo handling design, BOG management, custody transfer, IGC Code compliance, emergency systems.
Advanced Training for Oil Tanker Cargo Operations under STCW A-V/1-1-2 — required of Masters, Chief Mates, Chief Engineers, Second Engineers and any officer with immediate cargo responsibility on an oil tanker. Cargo handling design and equipment, loading and discharge with focus on stress and stability, inert-gas systems, tank cleaning, COW, vapour return.
Basic Training for Liquefied Gas Tanker Cargo Operations under STCW A-V/1-2-1 — minimum requirement for any seafarer with designated cargo duties on a gas carrier (LNG, LPG, ethylene, ammonia). Cargo properties, IGC Code overview, cargo containment systems, basic operations, emergencies.
Basic Training for Oil and Chemical Tanker Cargo Operations under STCW A-V/1-1-1 — minimum requirement for any seafarer with designated cargo duties on an oil or chemical tanker. Cargo properties, hazards, basic operations, fire prevention, emergencies. Pre-requisite for the advanced endorsements.
5-yearly refresher in advanced fire fighting for officers controlling fire-fighting operations.
Periodic refresher for designated medical-care officer on board; addresses telemedicine, MFAG updates, advanced life support.
Recommended periodic refresher in medical first aid, although STCW does not mandate the interval.
Refresher for masters, chief mates and OOWs on ships in polar waters; reinforces STCW V/4 basic competencies in ice navigation, hull stress in ice, polar emergencies.
5-yearly refresher for FRB operators; covers updates to launch and recovery procedures, casualty handling.
5-yearly refresher in operation of survival craft and rescue boats other than fast rescue boats; ongoing professional competence per STCW 2010.
5-yearly refresher for crew on ro-ro passenger ships covering crowd management, crisis management, evacuation, and passenger safety per STCW Reg. V/2.
Periodic refresher for tanker officers covering updates to ISGOTT, MARPOL, ESD, IGC Code where applicable.
Ammonia as marine fuel — emerging course aligned with the IGF Code amendments under development at IMO MSC 110+ (expected entry-into-force mid-2020s). Toxicity, leak detection, scrubber requirements for slip, double-walled fuel piping, bunkering protocol. Course content varies by training provider during the transition.
Basic / Advanced Training for service on ships subject to the IGF Code under STCW A-V/3 — required of crew on LNG-fuelled (or other low-flashpoint-fuelled) vessels. Cargo properties, fuel-storage and supply systems, leak and fire response, bunkering procedure, IGF Code structure.
Methanol as marine fuel — course aligned with IGF Code Part B-1 (MSC.539(107) — adopted 2023, entered into force 2024). Flashpoint and explosion characteristics, double-walled piping and bunkering, fire detection and suppression, crew training requirements under STCW V/3.
Australian Maritime Safety Authority CoC under Marine Order 70/71/72; STCW-compliant.
Government of India Directorate General of Shipping Certificate of Competency; STCW-aligned, common origin for Indian seafarers worldwide.
Dirección General de la Marina Mercante CoC; Spanish flag-state STCW certification.
Philippine Maritime Industry Authority CoC; primary certification body for Filipino seafarers under STCW.
Norwegian Maritime Authority CoC; STCW-compliant, recognised on most international flags.
Transport Canada Marine Certification under TP 2293; STCW-compliant for Canadian seafarers.
USCG Able Seaman rating unlimited; STCW A-II/4 / A-II/5 endorsement available.
United States Coast Guard Master licence for vessels up to 1,600 GRT (3,000 ITC); STCW endorsement available for international voyages.
USCG Master licence ≤3,000 GT; STCW Reg. II/2 endorsement available.
Person In Charge tanker endorsement on a USCG MMC; required for transferring liquid cargo on US tank vessels and barges.
BMP5 / piracy-area transit preparation — for Masters and Chief Mates planning transits of high-risk areas (Gulf of Aden, Indian Ocean, Gulf of Guinea, southern Red Sea). UKMTO/MDAT-GoG reporting, citadel use, hardening measures, armed-guard interface (PCASP), post-incident debrief and IMB reporting.
American Society for Non-Destructive Testing Level II qualification (UT, MT, PT, RT, ET); required for class-required NDT.
Class-society approval (DNV, LR, BV, ABS, ClassNK) for ultrasonic thickness measurement firms / operators carrying out class-required hull gaugings.
TWI Certification Scheme for Welding Inspectors Level 3.1; widely required for shipyard QA/QC and class-witnessed welding.
Ballast Water Management training — required by the BWM Convention (in force 2017) for officers responsible for BWM operations. BWMS operation, sampling and reporting, BWMP execution, port-state checks under D-2 standard, exemption regimes (D-1 exchange where still permitted).
Oil Spill Response training — required of crew designated to operate the ship's SOPEP (Shipboard Oil Pollution Emergency Plan) under MARPOL Annex I Reg 37. Scope of SOPEP, response equipment onboard, reporting under Article 8 of MARPOL, interface with shore response (OSRO) and flag-state authorities.
Basic Safety Training under STCW A-VI/1 — four mandatory modules: personal survival techniques (PST), fire prevention and fire-fighting (FPFF), elementary first aid (EFA), and personal safety and social responsibilities (PSSR). Required of every seafarer with designated duties on a sea-going ship. Refresher in PST and FPFF every five years; EFA and PSSR are one-time.
Bridge Resource Management (BRM) / Bridge Team Management under STCW A-II/1 and A-II/2. Human-element course covering leadership, situational awareness, communication, error-trapping, fatigue management, decision-making under pressure. Required for OOW and Master ranks; commonly refreshed every five years as part of CoC revalidation.
ECDIS generic training under STCW A-II/1 and IMO Model Course 1.27 — required of every deck OOW serving on a vessel that uses ECDIS as the primary means of navigation. Generic ECDIS theory and operational use; type-specific (vendor) training is a separate requirement before joining a ship with an unfamiliar ECDIS model.
Type-specific (vendor) ECDIS familiarisation — required by the ISM Code for any officer joining a vessel with an unfamiliar ECDIS model, in addition to the generic ECDIS course (STCW A-II/1). Typically a 1- or 2-day vendor course (Furuno, JRC, Transas / Wartsila, Sperry, Kongsberg, Raytheon) or an equivalent CBT module backed by onboard familiarisation.
Radar and ARPA at the management level under STCW A-II/2 — required of Master and Chief Mate. Builds on operational level: management of multi-target encounters, use of ARPA in restricted visibility, integration with ECDIS and AIS, vetting of ARPA performance after installation.
Radar Navigation and ARPA at the operational level under STCW A-II/1 — required of OOW. Range and bearing accuracy, target acquisition, true-vector vs relative-vector display, parallel indexing, anti-collision use of ARPA, performance limits. Often delivered with bridge simulator hours per IMO Model Course 1.07.
Ship Handling Simulator course (deck) — non-STCW but required by many flag states and by most pilot authorities for Master and Chief Mate. Covers manoeuvring characteristics, pivot point, squat, bank effect, tug operations, port-approach planning. Typically 5 days at an accredited simulator.
UK MCA Certificate of Competency (Deck) — issued by the Maritime and Coastguard Agency under the UK transposition of STCW. Pathway: cadet → OOW (STCW II/1) → Chief Mate (II/2) → Master Unlimited (II/2). Five-year validity with sea-time + medical revalidation.
Manufacturer-specific BWMS operator training (Alfa Laval PureBallast, Optimarin, Wärtsilä Aquarius UV/EC).
OEM-specific training on operation and maintenance of exhaust gas cleaning systems; required by some flag states under MARPOL Annex VI scrubber inspection regime.
Engine Room Resource Management under STCW A-III/1 and A-III/2 — engine-room counterpart to BRM. Watchkeeping team coordination, leadership, decision-making under engine-room emergencies, communication with bridge during failure events. Required for engineer OOW and management-level engineers.
Management-level competence in HV systems for chief engineers per STCW Reg. III/2 amendments.
High Voltage Operation and Safety under STCW A-III/2 (operational and management level) — required of engineers serving on vessels with HV (>1 kV) installations. Electrical safety isolation, switching procedures, arc-flash hazards, permit-to-work systems for HV work, switchgear maintenance.
OEM-issued course (e.g. MAN PrimeServ Academy, WinGD Training) on operation and maintenance of low-speed two-stroke main engines.
UK MCA Certificate of Competency (Engine) — issued by the Maritime and Coastguard Agency under the UK transposition of STCW. Pathway: cadet → OOW Engine (STCW III/1) → Second Engineer (III/2) → Chief Engineer Unlimited (III/2). Five-year validity with sea-time + medical revalidation.
OEM training (Wärtsilä Land & Sea Academy) on 4-stroke medium-speed diesel engines used in OSVs, ferries, smaller cargo ships.
CDI accreditation for chemical-tanker inspectors; covers IBC Code, CDI questionnaire, tank cleaning verification.
OCIMF accreditation for SIRE 2.0 tanker inspectors; rigorous assessment with 3-yearly revalidation.
RightShip accredited bulker inspector; conducts pre-fixture inspections and supports the dry-bulk vetting database.
ISPS Code Part B 13 Company Security Officer training; covers risk assessment, ship security plan approval, audit oversight.
ISM Code Section 4 DPA training; required before assuming the Designated Person role linking ship and shore management.
Crisis Management and Human Behaviour training for personnel serving on passenger ships under STCW A-V/2-2 — for officers with passenger-safety responsibility. Crowd dynamics in emergencies, casualty management, communications under pressure, multi-language announcements.
Crowd Management training for personnel serving on passenger ships under STCW A-V/2 — for all crew who assist passengers in emergencies. Crowd dynamics, evacuation procedures, communicating with passengers, lifesaving-appliance operation. Required for any rank rostered to a muster station role.
Familiarisation training for personnel serving on passenger ships under STCW A-V/2-1 — required of every crew member on a passenger vessel. Vessel layout, evacuation routes, passenger assistance, life-jacket donning instruction.
Davit-launched liferaft operation — required where the ship's lifesaving appliances include davit-launched liferafts (typical on offshore standby vessels and many passenger ships). Launching, recovery, weight-testing, davit maintenance.
Proficiency in Fast Rescue Boats under STCW A-VI/2-2 — qualifies the holder to take charge of a fast rescue boat (offshore standby vessels, ferries with FRBs). Surf launch and recovery, righting after capsize, search patterns, casualty recovery. Practical refresher every five years.
Proficiency in Survival Craft and Rescue Boats other than Fast Rescue Boats under STCW A-VI/2-1 — qualifies the holder to take charge of a survival craft or rescue boat in an abandon-ship situation. Launching, recovery, stability, sea-anchor, location signals, helicopter pickup. Practical refresher every five years.
Dynamic Positioning Advanced (Phase 4) per the IMO Nautical Institute scheme — for officers who hold the Limited DP certificate and require Unlimited. Advanced FMEA review, capability plots, drive-off and drift-off, IMCA M 117 / MTS DP guidance.
Dynamic Positioning Induction (Phase 1) per the IMO Nautical Institute scheme — entry-level DP course for officers serving on DP class 1, 2 or 3 vessels. Theory of DP system architecture (sensors, references, thrusters, power), watch responsibilities, FMEA basics. Followed by 60 days of DP sea time and the DP Simulator (Phase 2) before logbook accreditation.
STCW Reg. III/6 Electro-Technical Officer CoC; specialist electrical / electronic officer rank introduced 2010.
Enclosed Space Entry under SOLAS III/19 (the 2015 amendment introduced mandatory drills) — required of every seafarer who enters or rescues from an enclosed space. Atmospheric testing (O2, LEL, H2S, CO), permit-to-work, breathing apparatus, communication, rescue equipment, mandatory drill every two months.
Specialist enclosed-space-rescue training for designated rescue team members; goes beyond the SOLAS III/19 enclosed-space entry drill.
Basic first-aid + Automated External Defibrillator certificate; supplements but does not replace STCW medical first aid.
Hot Work training under SOLAS II-2/10 and the company's Permit-To-Work system — required of any crew who carry out welding, grinding, or open-flame work onboard. Risk assessment, hot-work permit issuance, fire watch organisation, gas freeing of confined spaces, isolation of paint and hydrocarbon stores. Typically refreshed annually as part of company SMS drills.
Institution of Occupational Safety and Health Managing Safely course; common refresher for shore-side managers and ship superintendents.
Entry-level IOSH HSE course for all employees; common terminal-side requirement.
Internationally recognised HSE qualification; widely required of marine superintendents, terminal supervisors, port HSE staff.
Competence to test and recharge self-contained breathing apparatus cylinders aboard ship; usually a manufacturer-issued certificate.
GMDSS General Operator Certificate under STCW A-IV/2 and ITU Radio Regulations Article 47 — mandatory for any officer designated to operate the GMDSS suite on a vessel in any sea area (A1, A2, A3, A4). DSC distress alerting, MF/HF and Inmarsat-C / FleetBroadband / Iridium operation, NAVTEX, EPIRB and SART maintenance.
GMDSS Restricted Operator Certificate under STCW A-IV/2 — for vessels operating only in sea area A1 (within VHF coverage of a coast station). Limited to VHF DSC distress alerting and routine VHF traffic; a vessel sailing into A2/A3/A4 requires a GOC holder onboard.
Helicopter Approach and Manoeuvring training — for OOW on vessels that receive helicopter visits. Bridge procedures during helicopter approach, communication with the pilot, course and speed orders, rescue-net and winching protocols.
Helicopter Landing Officer — non-STCW; required by OPITO and most North Sea / Brazilian / Australian offshore operators for personnel supervising helicopter operations on a vessel with a helideck. Pre-flight checks, deck-party briefing, fire-fighting in the event of crash, refuelling supervision, passenger handling.
Human Element, Leadership and Management at the management level under STCW A-II/2 and A-III/2 — required of Master, Chief Mate, Chief Engineer, Second Engineer. Strategic leadership, organisational culture, change management, mentoring, performance assessment of subordinates.
Human Element, Leadership and Management at the operational level under STCW A-II/1, A-III/1, A-VII/2 — required of all OOW. Workload and resource management, decision-making under pressure, leadership style, motivation, conflict handling. Often combined with BRM/ERM in delivery.
International Association of Marine Aids to Navigation V-103/2 supervisor course for Vessel Traffic Service shift supervisors.
IALA V-103/3 OJT trainer course for senior VTS operators conducting structured on-the-job training of new VTSOs.
ISPS Part A 17 PFSO training; required for the named security officer at every regulated port facility.
Institute of Marine Engineering, Science & Technology chartered status (CMarEng / CMarTech / CMarSci).
ICS Professional Qualifying Examinations / Diploma; pathway to MICS/FICS chartered status.
Lloyd's Maritime Institute introductory marine insurance certificate; recognised qualification for marine cargo / hull underwriters and brokers.
Nautical Institute professional membership (AFNI, MNI, FNI); requires demonstrated experience and CPD.
IMCA D 014 Diving Supervisor certificate for surface-supplied air diving; required for offshore supervisor work.
IMCA D 013 LST scheme for technicians operating saturation diving life-support systems.
Closed-bell saturation diver — IMCA D 015 logbook scheme; pre-eminent qualification for deep offshore work.
International Marine Contractors Association R 002 logbook scheme for trainee ROV Pilot Technicians; demonstrates competence to industry standard.
Pilot training meeting IMO Resolution A.960(23) recommendations; common minimum for entry-level pilots in many ports.
International Rope Access Trade Association Level 1 technician certificate; common requirement for hull/derrick/wind turbine inspection.
ISM Internal Auditor training — non-STCW; required by company QSE/SMS to qualify auditors for internal SMS audits under ISM Code Element 12. Audit planning, evidence collection, non-conformity reporting, root-cause analysis, audit-trail documentation. Refresher cadence is set by the company DPA.
ISPS Internal Auditor training — required by the company SSP to qualify auditors for the annual ISPS internal audit (ISPS Code A/13). Often delivered together with the ISM auditor course.
MLC 2006 Port State Control awareness — for Masters, Chief Officers, and Designated Persons Ashore. Reviews the MLC inspection process under Regulation 5.2 and Standard A5.2.1, the role of the DMLC Part I/II, the onboard complaints procedure under A5.1.5, and the typical PSC officer focus areas (rest hours, recruitment fees, accommodation, food, wages).
Lead Auditor for environmental management systems; relevant to ship operators tracking ISO 14001 EMS for vetting.
Lead Auditor for occupational health & safety management systems; relevant to ship operators with integrated SHEQ systems.
IRCA-registered Lead Auditor course for ISO 9001 quality management systems; common for shipyard, manning agency, port-facility QMS.
Lead Auditor course covering ILO Maritime Labour Convention 2006 inspection regime; used by RSO surveyors.
Information security management system implementer; relevant since IMO Resolution MSC.428(98) on cyber-risk management in SMS.
Training aligned with IMO MSC.428(98) and BIMCO Guidelines on Cyber Security On Board Ships v.4 (2020).
UK competent-person training for thorough examination of lifting equipment under LOLER 1998; widely accepted for shipboard cargo gear examination under ILO C152.
Competence training for personnel directing crane lifts and slinging loads on offshore installations.
OPITO Stage 3 competence-based assessment for offshore crane operators; covers static and dynamic lifts, personnel transfer, cargo handling.
UK MCA Master licence for commercial yachts under 200 GT; STCW-recognised.
UK MCA Master licence for large yachts up to 3000 GT.
UK MCA Master licence for commercial yachts under 500 GT; widely held in superyacht industry.
Royal Yachting Association coastal/offshore Yachtmaster certificate; commercially endorsed via MCA for yachts <200 GT in commercial use.
Highest RYA leisure-side certificate; ocean-going celestial navigation and full astro sight.
Medical Care under STCW A-VI/4-2 — required of every Master and any officer designated to take charge of medical care onboard. Builds on MEDFA: anatomy and physiology, advanced patient assessment, medication administration including controlled drugs, suturing and minor procedures, ship medical inventory under STCW Code, MEDEVAC and TMAS protocols. Refresher every five years.
Medical First Aid under STCW A-VI/4-1 — for seafarers designated to provide medical first aid onboard. Patient assessment, immediate trauma and medical emergencies (cardiac, stroke, sepsis, drowning), use of the ship medical guide and TMAS consultation, MEDEVAC coordination. Refresher every five years.
DP Operator certificate limited to DP Class 1 vessels; intermediate scheme bridging DP Induction and full DP Operator.
Five-day course for ETOs and electricians maintaining DP control systems; required for those issuing DP work permits or troubleshooting DP equipment.
5-yearly DP Operator revalidation by either 150+ days DP sea time, an approved DP simulator course, or an NI assessment.
OPITO Standard 5750 Basic Offshore Safety Induction & Emergency Training: 3-day course including HUET, fire, escape, first aid; mandatory for new offshore travellers worldwide.
OPITO Further Offshore Emergency Training: 1-day refresher for BOSIET, required every 4 years to remain valid for offshore travel.
Hydrogen-sulphide awareness and escape training for personnel working in sour environments; covers detection, escape sets, casualty handling.
Industry-standard induction for personnel new to UKCS oil and gas installations; covers hazards, control of work, manual handling, working at height.
Offshore tropical survival training including helicopter ditching, life raft, sea survival in warm-water environments.
Helicopter Underwater Escape Training tailored for tropical / warm-water regions; common requirement for SE Asia, West Africa, Brazil offshore work.
Offshore Installation Manager command-and-control simulator assessment for major emergencies; required for OIMs on UKCS installations.
Advanced Training for service on ships operating in polar waters under STCW A-V/4-2 — required for Master and Chief Mate of ships operating in polar waters. Advanced ice navigation, POLARIS risk-assessment, PWOM, search-and-rescue in polar conditions, ice-class limitations and operating restrictions.
Basic Training for service on ships operating in polar waters under STCW A-V/4-1 — required for officers serving on ships that operate in polar regions under the Polar Code. Ice and weather hazards, safe operation in low-temperature environments, ice-class limitations, crew-cold-weather safety.
Prevention of Bullying and Harassment training introduced under the 2026 STCW comprehensive review — mandatory for every seafarer once national administrations transpose. Covers definitions, reporting routes (onboard procedure under MLC 5.1.5, DPA, flag administration, ITF, ISWAN), the Master's responsibilities, and confidentiality protections. Schedule and rollout vary by flag state during the transition period.
Refrigerated Cargo Operations — non-STCW but required by major reefer-trade operators. Refrigeration cycle, cargo physiology, set-point and dew-point control, controlled-atmosphere (CA) cargoes, pre-trip inspection of integral reefer containers, plug-in/clip-on patterns on container ships.
Specialist tank-cleaning certificate (e.g. STASCO, Miracle) for chemical cargo cleanings; required by many vetting departments.
Security Awareness training under STCW A-VI/6-1 — required of every seafarer working on a ship subject to ISPS. Covers threat recognition, suspicious-package handling, communications, and the seafarer's role in maintaining the SSP. Mandatory across the fleet; one-time training but companies often refresh with annual security drills.
Security-related training for seafarers with designated security duties under STCW A-VI/6-2. For crew assigned a SSP role beyond awareness — gangway watch, screening, restricted-area control. One-time training; no formal refresher.
Ship Security Officer under STCW A-VI/5 — appointed in writing by the Company under ISPS A/12 and accountable to the Master for ship security. Maintains the Ship Security Plan (SSP), conducts security drills and exercises, audits security at the three security levels, liaises with the CSO and the PFSO. No formal refresher required, but companies typically renew with the SSP.
MLC 2006 Reg. 3.2 ship's cook certificate; required for cooks on ships ≥10 crew operating internationally.
OCIMF SIRE 2.0 inspector or vetting-coordinator preparation — for senior officers preparing a vessel for a SIRE 2.0 inspection. Covers the eight HVPQ chapters, the Person-Specific element, observation grading, the inspector reporting workflow, common findings and how to evidence corrective action.
Basic safety training for fishing vessel personnel under STCW-F 1995, distinct from STCW A-VI/1 BST.
Certificate of competency for engineers of fishing vessels under STCW-F 1995.
Certificate of competency for masters of fishing vessels under STCW-F 1995 (entered force 2012).
VTS Operator training — for personnel staffing a Vessel Traffic Service centre ashore (not for ship's officers). IMO Resolution A.857(20), IALA V-103/1 syllabus. Outside the seafarer scope; included here for completeness.