Y-codes closed 1 January 2023: the Y4, Y3, Y2 and Y1 certificate routes under MSN 1859 were closed to new applicants on 1 January 2023. If you are starting your engineering career now, you follow the MSN 1904 route below. Existing Y-code holders may revalidate and may convert to SV CoC routes via MIN 642.
"It replaces MSN 1859 (Amendment 1), MIN 524 and MIN 594."
"MSN 1859 (Amendment 1) will run parallel with this MSN until 31st December 2022. This will allow those with an Engineering Yacht Certificate of Competency (CoC) to complete their training or convert to a Small Vessel Certificate of Competency. You will still be able to revalidate existing Engineering Yacht or Tug restricted Certificates of Competency after this date."
MSN 1904 (M+F), cover page and summary · Read the full notice on gov.uk
MSN 1859 itself is now formally withdrawn, you can see the withdrawn MSN 1859 page on gov.uk for proof that the Y route is closed.
How the engineering career ladder works
Yacht engineering qualifications in the UK are governed by MSN 1904 (M+F) for the small-vessel route, and by MSN 1857 Amendment 1 for the merchant navy unlimited route. The small-vessel route is the standard path for engineers working on yachts up to 9,000 kW and 3,000 GT, which covers the vast majority of superyachts. Verify current requirements with the MCA at gov.uk/guidance/engineering-officers-and-ratings before applying.
Section 2.1 of MSN 1904 sets out the certificate structure: EOOW less than 9,000 kW and less than 3,000 GT (STCW VII and III/1), Chief Engineer less than 3,000 kW and less than 500 GT (STCW VII and III/3), and Chief Engineer less than 9,000 kW and less than 3,000 GT (STCW VII and III/2). All three are limited to service on "Fishing Vessels, Yachts, Tugs, Workboats, Standby, Seismic Survey, Oceanographic Research Vessels and Government Patrol Vessels", which is why the industry calls them small-vessel or SV tickets.
As with all professional yacht crew, STCW Basic Safety Training and an ENG1 seafarer medical are mandatory before you can work on any commercial yacht, regardless of the engineering route you follow.
The entry point for the current yacht engineering route under MSN 1904. AEC Level 1 is a five-day course covering the fundamentals of marine engineering. No sea time is required before enrolling, but sea time toward MEOL(SV) only begins counting after AEC1 is awarded. Minimum age 18. This course must be completed at an MCA-approved training centre. Day to day at this level you are the junior in the engine room: oil and filter changes, bilge checks, tender engines and daily walk-rounds, reporting to the Chief or, on smaller boats, the sole engineer. Book your STCW Basic Safety Training, ENG1 medical and AEC course through the training directory.
Sea time: none required to enrolAEC Level 2 is a five-day course building on AEC1. You must hold AEC1 before enrolling. No additional sea time is required. On completion of AEC2, you can begin accumulating sea time that counts toward the MEOL(SV) requirements. Most schools run AEC1 and AEC2 back to back over two weeks, so many crew knock out both in one trip, compare dates on the AEC and MEOL(SV) course page.
Sea time: none required to enrol; qualifying sea time begins after AEC2The first formal MCA CoC in the engineering ladder. The MEOL(SV) covers vessels with propulsion power between 200 kW and 750 kW. Two sea-time pathways: Pathway A requires 36 months dual-purpose deck and engineer service on vessels of 200 kW or more, of which at least 6 months must specifically be seagoing service in the engineering department; Pathway B requires 24 months as yacht engineer responsible for system maintenance on 200 kW or more vessels, with the same embedded 6-month seagoing requirement. Separately, a universal MCA recency rule applies to every CoC application: at least 6 months of your total qualifying service must fall within the 5 years preceding application. Yard and refit time is capped at 90 days. On yachts in this power band you are usually the sole engineer on board, covering main engines, generators, watermaker, air conditioning and the tender fleet, and you report directly to the captain. Find MEOL(SV) providers and the supporting medical and first aid courses in the directory.
Pathway A: 36 months dual-purpose service on 200 kW+ (incl. 6 months seagoing) · Pathway B: 24 months as yacht engineer on 200 kW+ (incl. 6 months seagoing) · Separately: 6 months of total service must fall within the last 5 years (MSN 1904)"This qualification will allow you to serve as Marine Engine Operator on Small Vessels with a propulsion (registered) power of between 200 kW and 750 kW, where STCW requirements do not apply."
The Pathway B sea-time requirement, verbatim: "24 months' onboard service as a Small Vessel engineer responsible for system maintenance on a Small Vessel of 200 kW or more in propulsion power of which at least 6 months must be seagoing service"
MSN 1904 (M+F), sections 3.1 and 3.2(b) · Read the full notice on gov.uk
Chief Engineer on small vessels up to 3,000 kW and 500 GT. Requires 6 months seagoing service as Second Engineer on qualifying vessels, with at least 6 months within 5 years preceding application. Training modules include SV Marine Diesel Engineering, SV Auxiliary Equipment I and II, SV Operational Procedures, and Chief Engineer Statutory and Operational Requirements. Governed by MSN 1904. At this rank you own the maintenance plan, the spares inventory and the engine room paperwork, typically running a one or two person department and answering to the captain and the management company ashore. Compare SV Chief Engineer courses on the yacht track.
Sea time: 6 months seagoing service as Second Engineer on qualifying vessels (MSN 1904)Chief Engineer on vessels up to 9,000 kW and 3,000 GT, covering most large superyachts. This is the top of the current small-vessel engineering route. SQA written examinations cover General Engineering Science I and II and Applied Marine Engineering. Requires HELM Management and Engine Room Resource Management at this level. While holding the SV Chief Engineer under 3,000 kW/500 GT CoC, the qualifying step is 6 months' additional seagoing service on vessels of at least 750 kW (MSN 1904 section 4.10(a)); always verify current figures with the MCA before applying. On the largest yachts in this bracket you lead an engine team of two to four, run yard and refit periods and the department budget, and rotational contracts become common at this level. See ERM courses, Second Engineer CoC prep and Chief Engineer CoC prep in the directory.
Sea time: 6 months additional seagoing service on 750 kW+ vessels, on top of holding the SV Chief <500 GT/<3,000 kW CoC (MSN 1904 section 4.10(a))The SV EOOW certificate: the watchkeeping rung
MSN 1904 also defines an SV Engineer Officer of the Watch certificate (less than 9,000 kW, less than 3,000 GT), the watchkeeping rung between MEOL(SV) and the Chief Engineer tickets. On yachts big enough to carry an engine team, the EOOW stands machinery watches and runs planned maintenance under the Second or Chief Engineer. The standard route entry requirements, verbatim from the notice:
"(a) Hold an Approved Engine Course I & II (AEC I & II); (b) Have completed 12 months' combined seagoing service and workshop training, including 6 months' seagoing service engaged in watchkeeping or Unmanned, and 5 months' seagoing service on vessels of at least 350 kW"
MSN 1904 (M+F), section 4.3 · Read the full notice on gov.uk
Compare providers for the SV EOOW and Chief Engineer yacht track, EOOW CoC preparation and EOOW orals preparation in the training directory.
Where the Y-codes fit: holders of legacy Y4, Y3, Y2 or Y1 certificates from before 1 January 2023 can still revalidate those certificates and convert to the new SV routes via MIN 642 conversion routes. If you are starting fresh, none of the Y-code routes are available to you, follow the AEC/MEOL(SV) path above.
What most engineering candidates come from
Engineers enter yachting from a range of backgrounds: marine engineering, electrical trades, HVAC, plumbing, refrigeration and diesel mechanics are all common starting points. Relevant trade certifications alongside STCW and ENG1 are the typical entry point. The AEC1 and AEC2 courses are accessible without a marine engineering background, though prior mechanical knowledge is beneficial.
PDSD and larger-vessel endorsements
Engineering crew on vessels over 500 GT must also hold PDSD (Proficiency in Designated Security Duties). Crowd Management and Crisis Management endorsements are required on passenger-carrying yachts for senior crew with muster responsibilities. These apply regardless of engineering rank.
How much do superyacht engineers earn?
Engineering is one of the best paid departments at sea, and Chief Engineer pay climbs sharply with vessel size:
| Role | Indicative monthly pay |
|---|---|
| Junior / 3rd Engineer | €3,500 to €5,000 |
| Second Engineer | €4,500 to €7,000 |
| Chief Engineer | €6,000 to €20,000 |
Indicative monthly ranges in euros, the industry standard currency. Pay scales with vessel size, rotation and flag, and excludes tips and bonuses. Figures are blended from published 2026 yacht crew salary guides (YPI Crew, Foreland Marine and others); always confirm current rates before relying on them.
Where to train: superyacht engineering courses
The engineering route runs from your first AEC ticket up to an unlimited Chief Engineer Certificate of Competency. Compare providers, dates and locations in the YachtSync training directory.
- STCW Basic Safety Training
- ENG1 seafarer medical
- AEC, MEOL(SV) and the small-vessel tickets
- Small-vessel EOOW and Chief Engineer, yacht track
- Engineer Officer of the Watch (STCW III/1)
- Second Engineer Officer Certificate of Competency
- Chief Engineer Officer Certificate of Competency
- Engine Room Resource Management
Official source documents
These are the documents an MCA examiner will hold you to. Read them before you book anything:
- MSN 1904 (M+F), UK requirements for Engineer Officer (Small Vessel) Certificates of Competency: gov.uk landing page · full PDF
- MSN 1859 (M+F) Amendment 1, the old Y-code notice, now withdrawn: withdrawn notice on gov.uk
- Engineering officers and ratings hub, the MCA's live guidance index: gov.uk/guidance/engineering-officers-and-ratings
- MSN 1865 (M) Amendment 1, STCW basic training and safety functions: notice on gov.uk
- MSN 1886 (M+F) Amendment 3, the ENG1 medical examination system: notice on gov.uk
Frequently asked questions
What engineering qualifications do I need to work on a superyacht?
Start with STCW BST and ENG1, mandatory for all professional crew. Then AEC Level 1 and Level 2 at an MCA-approved centre. After that, accumulate the qualifying sea time for MEOL(SV) and work toward Chief Engineer. Browse relevant training courses in the Training Directory.
Are the Y-codes still available?
No. The Y4, Y3, Y2 and Y1 routes closed to new applicants on 1 January 2023. New engineers follow the MSN 1904 route (AEC1, AEC2, MEOL(SV)). Existing holders can revalidate and convert via MIN 642.
What is the MEOL(SV)?
The Small Vessel Marine Engine Operator Licence is the first formal MCA engineering CoC in the current route. It covers vessels 200 kW to 750 kW and requires either 36 months dual-purpose service or 24 months as yacht engineer on qualifying vessels, plus STCW BST, PSCRB, Advanced Fire Fighting, Medical First Aid, AEC1 and AEC2.
How do I become a Chief Engineer on a superyacht?
The MSN 1904 path runs: AEC1, AEC2, MEOL(SV), SV Chief under 3,000 kW/500 GT (6 months as Second Engineer), then SV Chief under 9,000 kW/3,000 GT. Each stage requires MCA examinations. Verify current requirements at gov.uk/guidance/engineering-officers-and-ratings.
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Related: All career pathways · Deck career path · ETO career path · Galley career path · Interior career path · STCW guide · ENG1 guide