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USCG Master License Requirements - Merchant Mariner Credential

USCG Master License Requirements (General, Sea Service and Other) by U.S. Coast Guard

limited master

A Master Mariner is ships topmost sailor who is qualified to be in charge of a merchant vessel , and is frequently referred to in non-official sources as a captain.

The captain is responsible for its safe and efficient operation, including - ship's seaworthiness, ship's safety and Security conditions, Cargo operations, navigation, crew management and more.

The master is in command of a merchant ship at all times and regulates the proper daily transactions and handles the legal affairs on maritime issues.

merchant ship

General Requirements for National Master License

  • Age: 21 years of age.
  • TWIC (Transportation Workers Identification Card)
  • Medical Certificate
  • Drug testing compliance 
  • Sea Service letters or discharges

USCG Master Unlimited OC or NC License Requirements

  • Sea Service Recency: 90 days in the past 3 years on vessels over 100 GRT to include 45 days on vessels over 1,600 GRT.

USCG Master Unlimited Sea Service Requirements

  • 360 days of service as Chief Mate on Ocean/NC or Great Lakes of self-propelled vessels,

    • Note: Service as Master on any vessel over 100 GRT, including trade restricted, will meet the requirement as C/M. The service must be within the scope of the MMC with regards to vessel type, and/or tonnage OR

  • 360 days of service, while holding a license or endorsement as Chief Mate of Ocean or Near Coastal, OF WHICH

    • At least 180 days of service as Chief Mate on Ocean or Near Coastal waters AND
    • Service as OICNW accepted on a 2 for 1 basis (360 days as 2nd or 3rd Mate equals 180 days of creditable service).
    • Note: Service as Master on any vessel over 100 GRT, including trade restricted, will meet the requirement as C/M as long as C/M is held at the time of service. The service must be within the scope of the MMC with regards to vessel type, and/or tonnage. OR

  • 720 days of service, while holding a license or endorsement as Master of GL &/or Inland of AGT under the authority of the license held & examinations

Unlimited Tonnage

  • All required service is on vessels of 100 GRT or more AND
  • 50% of the required service is on vessels 1600 GRT or more or a tonnage limitation may apply.

Tonnage Limitation

  • Tonnage Limitation may be issued if 50% of the required service is not on vessels 1600 GRT or more; however, ALL required service MUST be on vessels 100 GRT or more. Limited to max tonnage on which 25% of experience is obtained rounded up to the nearest 1,000 GRT, OR
  • Limited to 150% tonnage which 50% of service is obtained rounded up to the nearest 1,000 GRT WHICHEVER IS GREATER. When the calculated limitation equals or exceeds 10,000 GRT, the applicant is issued an endorsement without a tonnage limitation.

Sail or Auxiliary Sail Endorsement

  • 360 days of deck service on sail or Auxiliary Sail vessels. (Note: Tonnage for Sail or Auxiliary Sail endorsements must be calculated separately)
  • Unlimited Tonnage - 360 days of deck service on sail or auxiliary sail vessels of 100 GRT or more, AND
  • 180 days on sail or auxiliary sail vessels of 1600 GRT or more, or a tonnage limitation may be issued if 50% of the required service is not on vessels of 1600 GRT or more, AND,
  • Complete CG exam module for Auxiliary Sail or approved Auxiliary Sail course.

Other Requirements

Exams

  • Applicants for Master AGT Oceans, when upgrading from Chief Mate endorsement NO further exams required, provided mariner has been examined for Chief Mate Unlimited tonnage.

NOTE: A person holding this endorsement may qualify for an STCW endorsement, according to § 11.305.

USCG Master 500/1600 Ton OC or NC License Requirements

  • Recency of Sea Service:  90 days in the past 3 years on vessels of 50 GRT for Master 500 GRT and vessels of 100 GRT for Master 1600 GRT. Engine Department experience on vessels of the appropriate tonnage may be used for recency.

Master Less Than 1600 GRT Sea Service Requirements

  • 1440 total days of service, in any position or department, on Ocean, Near Coastal or Great Lakes waters, OF WHICH

    • Service on inland waters, other than GL, may substitute for up to 720 days of the total required service., AND
    • 720 days of service on vessels of more than 100 GRT, AND
    • 720 days of service MUST have been as a master, mate; master or mate (pilot) of towing vessels, or equivalent position while holding an endorsement as master, mate, master or mate (pilot) of towing vessels, AND
    • 360 days of the service as master, mate, or equivalent position, must have been on vessels of more than 100 GRT; OR

  • 360 days of service as master/mate or master/mate T/V’s on Ocean or Near Coastal waters on vessels of more than 100 GRT while holding a license or MMC as mate less than 1600 GRT OC or master/ mate T/V’s.

Eligibility for Other Endorsements

  • Mariner holding an endorsement as Chief Mate Oceans/NC self-propelled vessels 1,600 GRT or more is eligible for this endorsement without further exam.
  • 2nd Mate Oceans/NC of 1600 GRT or more is eligible for this endorsement upon completion of a limited examination.
  • Chief Mate NC or Oceans of Unlimited Tonnage is eligible for this endorsement without service or examination.

Master Less Than 500 GRT Sea Service Requirements

  • 1080 days of service on Ocean, Near Coastal or Great Lakes waters, OF WHICH

    • Service on inland waters, other than GL, may substitute for up to 540 days of the total required service., AND
    • 720 days of service MUST have been as a master, mate, or equivalent position while holding an endorsement as master, mate, or Operator of Uninspected Passenger Vessels, AND
    • 360 days of the service as master, mate, or equivalent position, must have been on vessels over 50 GRT; OR

  • 360 days of service on Ocean or Near Coastal service on vessels more than 50 GRT as master, mate, master or mate of self-propelled or towing vessels while holding a license or MMC as mate less than 500 GRT OC, OR
  • Hold a license or MMC as Master or Mate of towing vessels NC or OC, AND, provide 360 days of service as a Master or Mate of Ocean or N/C Towing Vessels AND completion of a limited examination (Limited exam allowed for any Master of T/V with or without tonnage limitation)

Endorsements and Other Requirements

Table: Master Less Than 500/1600 GRT  Endorsements and Other Requirements Credits: USCG 

  • A person holding Master 1600 may qualify for an STCW endorsement, according to § 11.311.
  • A person holding Master 500 may qualify for an STCW endorsement, according to § 11.309, 11.317, 11.319 and 11.321

USCG Master 200 Ton OC License Requirements

  • Seagoing Recency: 90 days in the past 3 years on vessels. Engine Department experience on vessels of the appropriate tonnage may be used for recency since overall service does not have to be on deck.

Master 200 OC Sea Service Requirements

  • 1080 total days of service, in any position or department, on Ocean, Near Coastal or Great Lakes waters, OF WHICH service on inland waters may substitute for up to 50% of the total required service AND 720 days MUST have been as master, mate, or equivalent position while holding a MMC endorsement as master, as mate, or as Operator of Uninspected Passenger Vessels, OR
  • 720 days as a Master or Mate of Ocean or N/C Towing Vessel and completion of an examination

Master 200 OC Endorsements (Optional)

  • Sail or Auxiliary Sail: 360 days on sail or auxiliary sail vessels, (Note: Tonnages for Sail or Aux Sail endorsements must be calculated separately for endorsements over 100 GRT) / 200 GRT - 90 days (25%) of service on vessels of 101 GRT or above, OR 180 days (50%) of service on vessels over 67 GRT / Complete CG exam module for Auxiliary Sail or approved course for Auxiliary Sail
  • Assistance Towing: Complete CG exam module for Assistance Towing or approved Assistance Towing course.
  • STCW: A person holding this endorsement may qualify for an STCW endorsement, according to 11.315, 11.317, 11.319 and 11.321.

Other Requirements

  • First Aid
  • CPR

USCG Master 200 Ton NC License Requiremets

  • Sea Service Recency:  90 days in the past 3 years on vessels. Engine Department experience on vessels of the appropriate tonnage may be used for recency since overall service does not have to be on deck.

Master Less Than 200 NC Sea Service Requirements

  • 720 total days of service, in any position or department, on Ocean, Near Coastal or Great Lakes waters, OF WHICH service on inland waters may substitute for up to 360 days of the total required service, AND 360 days must have been as a master, mate, or equivalent position while holding an endorsement as master, as mate, or as operator of uninspected passenger vessels; OR
  • 360 days as a Master or Mate of Ocean or N/C Towing Vessels and completion of an examination

Master Less Than 200 Endorsements


Table: Master of Self-Propelled Less Than 200 GR Endorsements Credits: USCG 

  • A person holding this endorsement may qualify for an STCW endorsement according to 11.315, 11.317, 11.319 or 11.321

USCG Master Unlimited GL and Inland License Requirements

  • Recency: 90 days in the past 3 years on vessels over 100 GRT to include 45 days on vessels over 1,600 GRT.

Master Unlimited GL Sea Service Requirements

  • 360 days of service as Mate or FCP while acting in the capacity of 1st Mate of Great Lakes vessels of 1600 GRT or more while holding a license or MMC endorsement as Mate Inland or FCP of Great Lakes and Inland self-propelled vessels of Unlimited tonnage; (service on near coastal or inland waters does not apply) OR
  • 720 days of service as Master Inland vessels of 1600 GRT or more on inland waters, excluding the Great Lakes; (service on near coastal waters or Great Lakes does not apply) OR
  • 360 days of service upon Great Lakes while holding an Officer endorsement as Mate or FCP of GL & INL of vessels 1600 GRT or more, OF WHICH:

    • At least 180 days of service as 1st Mate
    • Service as 2nd Mate accepted: 2 for 1basis for a max of 180 days.

Master Unlimited Inland Sea Service Requirements

  • 360 days service as FCP (other than canal & small lakes routes) or Mate of Great Lakes or Inland self-propelled vessels of 1600 GRT or more while holding a license or MMC endorsement as Mate inland or FCP of Great Lakes and Inland self-propelled vessels of unlimited tonnage; (service on near coastal waters does not apply); OR
  • 720 days of service performing bridge watchkeeping duties under the supervision of the master or a qualified officer, while holding a mate/ FCP license or officer endorsement. (Mate not specified here may be 3rd Mate, 2nd Mate, or Mate 500/1600 NC/Oceans)

Unlimited Tonnage

  • All required service is on vessels 100 GRT or more, AND 50% of the required service on vessels 1600 GRT or more or a tonnage limitation may apply. Any sea service on ATB’s, dual or push mode ITB’s or any towing vessel with barges, refer to 46 CFR 11.211 (d) and NVIC 2-81 for tonnage calculation

Tonnage Limitation

  • Tonnage Limitation may be issued if 50% of the required service is not on vessels over 1600 GRT and all experience is on vessels 100 GRT or more.
  • Limited to max tonnage on which 25% of experience is obtained rounded up to the next 1,000 GRT, OR
  • Limited to 150% tonnage which 50% of service is obtained rounded up to the next 1,000 GRT, WHICHEVER IS GREATER. (Minimum 2000 GRT limitation,) When total equals or exceeds 10,000 GRT mariner is issued an endorsement without a tonnage limitation

Other Requirements

  • First Aid
  • CPR
  • Approved Basic Fire Fighting Course within 5 years of application date (unless previously met) Valid STCW BT is acceptable.
  • Advanced Fire Fighting Course within 5 years of application date (unless previously met) Valid STCW Advanced Firefighting is acceptable.
  • Radar Observer - May use expired certificate for RIG but RADAR will not be endorsed on the MMC if expired.

USCG Master 500/1600 Ton GL and Inland License Requirements

  • Sea Service Recency: Master 500 - 90 days in the past 3 years on vessels of 50 GRT or more. Master 1600 - 90 days in the past 3 years on vessels of 100 GRT or more. Engine Department experience on vessels of the appropriate tonnage as noted may be used for recency since overall service does not have to be on deck.

Master 1600 GRT GL and Inland Sea Service Requirements

  • 1080 total days of service, in any position or department, on vessels, OF WHICH

    • 540 days of service on vessels over 100 GRT, AND
    • 360 days of service as Master, Mate, or equivalent position on vessels 100 GRT or more while holding an Officer Endorsement as Master, Mate, or Master Towing, OR

  • 180 days as operator of vessels 100 GRT or more while holding Master of T/V.

Master 500 GRT GL and Inland Sea Service Requirements

  • 1080 total days of service, in any position or department, on vessels, OF WHICH

    • 360 days of service as Master, Mate, or equivalent position on vessels 50 GRT or more while holding an Officer endorsement as Master, Mate, OUPV, OR

  • 1260 total days of service, in any position, on vessels, OF WHICH

    • 180 days of licensed service as Master of Towing (with or without a tonnage limit) vessels and completion of a limited exam, AND
    • 720 days of service while holding Master or Mate (Pilot) of Towing or Mate

Sail or Auxiliary Sail Endorsement

  • 360 days on appropriately sized sail or auxiliary sail vessels,

    • Master Less than 500 GRT - All required service over 50 GRT
    • Master Less than 1600 GRT - All required service over 100 GRT, AND,

  • Complete CG exams or Approved course

Other Requirements

National Master 200 Ton GL and Inland License Requirements

  • Recency of Sea Service: 90 days in the past 3 years on any vessel. Engine Department experience may be used for recency since overall service does not have to be on deck.

Master Less Than 200 Sea Service Requirements

  • Great Lakes: 360 total days of service, in any position or department, OF WHICH:

    • 180 days must have been as a Master, Mate, or equivalent position while holding a license or endorsement as Master, Mate, Master or Mate (Pilot) of towing vessels, or OUPV, AND
    • 90 days of service on Great Lakes

  • Inland: 360 total days of service, in any position or department, OF WHICH:

    • 180 days must have been as a Master, Mate, or equivalent position while holding a license or endorsement as Master, Mate, Master or Mate(pilot) of towing vessels, or OUPV,

Sail or Auxiliary Sail Endorsement (Optional)

  • 180 days on sail or auxiliary sail vessel (Tonnages for Sail or Aux Sail endorsements must be calculated separately for endorsements over 100 GRT)
  • 200 GRT: 45days (25%) of service on sail or auxiliary sail vessels of 101 GRT or above OR 90 days (50%) of service on sail or auxiliary sail vessels of 67 GRT or above
  • Complete CG Auxiliary Sail exam module or approved Auxiliary Sail course.

Commercial Assistance Towing Endorsement

  • Complete CG Assistance Towing exam module or approved Assistance Towing course.

Other Requirements

  • First Aid
  • CPR

USCG Master OSV Less Than Or More Than 1600GRT/3000GT License Requirements

  • Recency of Seagoing: 

    • Master LT 1,600 GRT/3,000 GT: 90 days in the past 3 years on vessels of 100 GRT or more
    • Master GT 1,600 GRT/3,000 GT: 90 days in the past 3 years on vessels of 100 GRT or more with 45 days on vessels of 1,600 GRT/3,000 GT.

Master OSV Less Than (<) 1600 GRT/3000 GT Sea Service requirements

  • 720 days of service as mate, chief mate, or master of ocean or near-coastal and/or Great Lakes on self-propelled vessels of more than 100 GRT.

    • Service on inland waters may substitute for up to 360 days of the required service AND
    • At least 360 days of the required experience must be served as chief mate (*Master may be used for Chief Mate).

Tonnage Increase to More Than (>) 1600 GRT/3000 GT (Not to Exceed 10,000 GRT/GT)

  • 720 days of service as mate, chief mate, or master of ocean or near-coastal and/or Great Lakes on self-propelled vessels of more than 100 GRT (may have been met previously) AND

    • At least 360 days of the required experience must be served as chief mate (Master may be used for Chief Mate) AND
    • 360 days as mate, chief mate, or master of ocean or near-coastal and/or Great Lakes on self-propelled vessels of 1600 GRT/3000 GT or more (if mariner does not have service on vessels of 1,600 GRT/3,000 GT a tonnage limitation will may be placed on the officer endorsement).

Tonnage Limitation

  • A Tonnage Limitation may be issued if 50% of the required service is not on vessels over 1600 GRT/3000 GT; however, ALL required service MUST be on vessels over 100 GRT.
  • Limited to max tonnage on which 25% of experience is obtained rounded up to the next 1,000 GRT/GT, OR
  • Limited to 150% tonnage which 50% of service is obtained rounded up to the next 1,000 GRT/GT WHICHEVER IS GREATER. Tonnage limitation on endorsement must not exceed 10,000 GRT/GT.

Master OSV valid on Tank Vessels

  • Meet requirements for Master OSV 10,000 GRT / 10,000 GT.
  • Successfully complete the examination for national endorsement for Chief Mate/Master Unlimited (non-trade restricted) for the appropriate route applied.

Other Requirements

  • First Aid
  • CPR
  • Approved Basic Fire Fighting Course within 5 years of application date (unless previously met). STCW BT is acceptable.
  • Advanced Fire Fighting Course within 5 years of application date (unless previously met). STCW Advanced Firefighting is acceptable.

USCG Master OSV Restricted to Liftboats License Requirements

  • Sea Service Recency:

    • Master OSV Less Than 1600 GRT: 90 days in the past 3 years on vessels of 100 GRT or more
    • Master OSV Greater Than 1600 GRT: 90 days in the past 3 years on vessels of 100 GRT or more to include 45 days on vessels of 1,600 GRT or more.

Master OSV Less Than 1600 GRT/3000 GT Restricted to Service on Liftboats

  • 720 days of service as mate, chief mate, or master of ocean or near-coastal and/or Great Lakes on self-propelled vessels of more than 100 GRT.

    • Service on inland waters may substitute for up to 360 days of the required service
    • At least 360 days of the required experience must be served as chief mate (service as master will meet this requirement)

  • For endorsements restricted to liftboats, service on Liftboats will be credited 1:1 or day for day without regard to whether the liftboat was underway or elevated at the time of service

Master OSV Greater Than 1600 GRT/3000 GT Or More Restricted to Service on Liftboats (Not To Exceed 10,000GRT/GT)

  • 720 days of service as mate, chief mate, or master of ocean or near-coastal and/or Great Lakes on self-propelled vessels of more than 100 GRT AND

    • At least 360 days of the required experience must be served as chief mate and be obtained on vessels of 1600 GRT/3000 GT or more or a tonnage limitation may apply.

  • For endorsements restricted to liftboats, service on liftboats will be credited 1:1 or day for day without regard to whether the liftboat was underway or elevated at the time of service.

Tonnage Limitation

  • A Tonnage Limitation may be issued if 50% of the required service is not on vessels over 1600 GRT/3000 GT; however, ALL required service MUST be on vessels over 100 GRT.
  • Limited to max tonnage on which 25% of experience is obtained rounded up to the next 1,000 GRT/GT, OR
  • Limited to 150% tonnage which 50% of service is obtained rounded up to the next 1,000 GRT/GTWHICHEVER IS GREATER. Tonnage limitation on endorsement must not exceed 10,000 GRT/GT

Other Requirements

  • First Aid
  • CPR
  • Approved Basic Fire Fighting Course within 5 years of application date (unless previously met) Valid STCW BT is acceptable.
  • Advanced Fire Fighting Course within 5 years of application date (unless previously met) Valid STCW Advanced Firefighting is acceptable.

Other Important Notes

  • Renewal of Deck Officer Endorsement: Liftboat service may be used for renewal of any deck officer endorsement and will be credited day for day without regard to whether the liftboat was underway or elevated at the time of service.
  • Removal of Restriction to Liftboats: Liftboat service will be credited 1:1 or day for day when the vessel is underway. Liftboat service while the vessel is elevated will be credited 1:2 (1 day of credited service for 2 days served) for up to 50% of the required service. Note - Service may also be credited as noted here for any deck officer endorsement.

USCG Examinations