Sea Service & Days at Sea - OOW, M500/3000 and M200
Officer of the Watch (Yachts less than 3000gt)
MSN 1858 (M) Amendment 1
Have (since the age of 16 years) a minimum of 36 months Onboard Yacht Service, in vessels of any size, including not less than 365 days Sea Service in vessels of 15 metres or over in loadline length, where the Sea Service is:
This means - you must have worked on boats for at least 3 years, and one of those years must be on a boat over 15m. Note the difference between Onboard Yacht Service and Sea service. Onboard Yacht Service is the time spent signed on a boat irrespective of the yacht’s activity.
i. A minimum of 250 days Actual Sea Service, and
Sea Service: is the time spent at sea, which may include time at anchor, river and canal transits associated with a passage. A minimum of 4 hours of working duty in 24 hours would count as 1 full day.
Time spent at anchor may be accepted as a day at sea if it is associated with a 24-hour passage. This means that the period at anchor must be temporary, e.g., waiting for a berth, delayed due to bad weather conditions, where the departure is postponed. If you conclude your trip and go to anchor (and not a berth), that is stand-by service.
Prior to the CoC you did not have time in the bridge so a day away from the dock in any situation is considered as a learning training day.
ii. The balance of 115 days any combination of the following:
Further Actual Sea Service
Stand-by Service to a maximum of 14 consecutive days may be counted at one time, but on no occasion may a period of standby service exceed that of the previous voyage;
Is the time immediately following a voyage while the vessel is under preparation for a subsequent voyage. A maximum of 14 consecutive days may be counted at one time, but on no occasion may a period of standby service exceed that of the previous voyage. Therefore, under no circumstances can your total standby service exceed your actual seagoing service. e.g going from Monaco to Gibraltar, refuelling, buying tea bags at Morrisons, having a pint, then waiting for a weather window to cross the Atlantic.
Yard Service to a maximum of 90 days continuously or in separate periods
Is a time when standing by a build, refit or repair. Not just for general maintenance along side etc.
Hence, you require 250 days of actual sea service plus 115 days of either more sea, standby or yard service!
For the Master 500gt you need
Once you have the OOW ticket then you are expected, when not on the dock, to be running watches. As you are a qualified watchkeeper.
Watchkeeping service is the actual seagoing service spent as a watchkeeping officer in full charge of navigational watch for no less than 4 out of every 24 hours while the vessel is engaged on voyage.
Hence for your Master 500gt ticket the sea requirements are different:
“Have completed a minimum of 12 months’ onboard yacht service as a deck officer, including at least 120 days watchkeeping service, in vessels of 15 metres or over in load line length while holding an OOW yachts, less than 3000 GT, II/1 Certificate of Competency; “
For the Master 3000gt you need
“Have a minimum of 24 months Onboard Yacht Service as a Deck Officer, including not less than 240 days Watchkeeping Service whilst holding an accepted OOW STCW Reg. II/1 (Yachts less than 3000gt) CoC. All of this service must be completed in vessels of 15 metres or over in loadline length and include 12 months in vessels of 24 metres or over in load line length, or six months in vessels of 500gt or more”
Watchkeeping service is actual sea service spent as a watchkeeping officer in full charge of a navigational watch for not less than 4 out of every 24 hours while the vessel is engaged on voyage.
Watchkeeping service may be recorded on a cumulative basis.
This means that every 4 hours watchkeeping accrued may be counted as 1 day of watch keeping service and does not need to be completed in a 24 hour period. Time spent at anchor associated with a passage, whilst the Officer is engaged in a bridge watch and if this passage is part of the same 24 hour voyage, can also be accepted. Completing more than 4 hours watchkeeping within a 24 hour period cannot be counted as more than 1 day watchkeeping time, e.g. a 12 hour watch within a 24 hour period can only be counted as 1 day of watchkeeping time.
Proof of onboard yacht service will need to be documented in either:
Merchant Navy discharge book supported by testimonials (Annex A); or
Certificates of discharge (Annex B) supported by testimonials; or
Similar MCA-approved service record book.
Sea service needs to be verified - MIN 543
“The MCA requires evidence of qualifying sea service in support of seafarer’s applications for a Notice of Eligibility (NoE) to be in the form of a correctly completed Sea Service Testimonial (SST)"
How do we do this?
⚠️ “Failure to do this will cause severe processing delays of around 160 days in the issue of your NOE” - MCA.
Min 543 provides further information for obtaining Sea Service Verification.
The MCA has agreed to a permanent switchover that resulted in a huge increase in efficiency and backlog.
PYA - non-profit, trade association. It is not a union. It’s primary mission is to represent the interests of professional yacht crew from around the world.
Nautilus - is a trade union for superyacht crew.
Take the time to make sure you are filling our your Sea Time correctly - both have various tips and information on their websites.
M200
While holding an RYA Yachtmaster Offshore or IYT Master of Yachts Limited certificate have completed 6 months’ seagoing service;
Master Code Vessels -<200 GT, OOW <500 GT – There are no requirements to provide sea service testimonials unless you are converting from an OOW unlimited (Merchant) CoC, whereby you must demonstrate 3 months’ seagoing sevice on vessels of between 15 metres and 24 metres or under 200 GT.
A company letter from the vessel owner or operator will be accepted as evidence.
This means you do not need to have your seatime verified by PYA and Nautilis, you just have to fill out your sea time on the MSF 4343 form - See below.
Any questions, give us a shout

