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.

• National Master General Requirements
• Master Unlimited OC or NC
• Master 500/1600 OC or NC
• Master 200 OC
• Master 200 NC
• Master 100 NC
• Limited Master 100/Limited OUPV
• Master Unlimited GL and Inland
• National Master 500/1600 GL and Inland
• Master 200 GL and Inland
• Master 100 GL and Inland
• Master of Towing OC, NC, GL-IN, WR
• Master OSV Less Than OR More Than 1600GRT/3000GT
• Master OSV Restricted to Liftboats
• USCG Examinations

You may also read: International Maritime Organization (IMO) STCW requirements for Master

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 of appropriate tonnage

USCG Master Unlimited Sea Service Requirements

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

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 exams or Approved course.

Other Requirements

• First Aid (completed within 1 year)
• CPR
• Approved Basic and Advanced Fire Fighting Course

USCG Master 500/1600 Ton OC or NC License Requirements

• Recency of Sea Service:  90 days in the past 3 years on vessels of appropriate tonnage. 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 1600 GRT Sea Service Requirements

• Service on inland waters, other than GL, may substitute for up to 720 days of the total required service., AND 2. 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.
• 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 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)
• Note: Any service towards an OC, NC or STCW 500/1600 endorsement will be credited as - Service on GL will be credited day for day; Service on inland waters, other than GL, may substitute for up to 50% of the total required service; and Service on vessels to which STCW applies will be credited day for day.

Endorsements and Other Requirements

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

USCG Master 200 Ton OC License Requirements

• Seagoing Recency: 90 days in the past 3 years on vessels of appropriate tonnage. 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, other than GL, 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

Sail or Auxiliary Sail Endorsement

• 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

Commercial Assistance Towing Endorsement

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

Other Requirements

• First Aid
• CPR

USCG Master 200 Ton NC License Requiremets

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

Master Less Than 200 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, other than GL, 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
• Note(1): Any service towards an Oceans or NC endorsement will be credited as - m Service on GL will be credited day for day; Service on inland waters, other than GL, may substitute for up to 50% of the total required service; and Service on vessels to which STCW applies (inland or NC) will be credited day for day.
• Note (2): For those vessel listed in 11.301(h), the holders of this endorsement are considered to be in compliance with the STCW Convention (incorporated by reference, see 11.102) while operating within the limitations of this endorsement, without further endorsement.
• Other Requirements: First Aid, and CPR

Master Less Than 200 Endorsements

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

USCG Master 100 Ton NC License Requirements

• Recency of Seagoing:  90 days in the past 3 years on vessels. Experience gained in the engine department on vessels of appropriate tonnage may be creditable for up to 90 days of the service requirements.

Master Less Than 100 Sea Service Requirements

• 720 days of service in the deck department on Ocean, Near Coastal or Great Lakes waters, OF WHICH service on inland waters, other than GL, may substitute for up to 360 days of the total required service.
• Note (1): Any service towards an OC, NC or STCW endorsement will be credited as service on GL will be credited day for day; service on inland waters, other than GL, may substitute for up to 50% of the total required service; service on vessels to which STCW applies (inland or NC) will be credited day for day
• Note (2): For those vessel listed in 11.301(h), the holders of this endorsement are considered to be in compliance with the STCW Convention (incorporated by reference, see 11.102) while operating within the limitations of this endorsement, without further endorsement.

Master Less Than 100 Endorsements & Other Requirements

Table: Master of Self-Propelled Vessels of Less Than 100 GRT Endorsements and Other Requirements Credits: USCG 

USCG Limited Master 100 Ton / Limited OUPV License Requirements

• Must have OCMI approval

USCG Limited Master Sea Service Requirements

(Formal Camps, Yacht Clubs, Educational Institutions, and Marinas) 

• 120 days service in the operation of the type of vessel specified on the requested endorsement;  Recency per the OCMI approval; Safe Boating course completed within 5 years before date of application; and  Pass a limited examination.
• Sail or Auxiliary Sail endorsement, ONLY authorized for NC waters: 120 days service on sail or auxiliary sail vessels, AND Pass the CG Auxiliary Sail exam module or an approved Auxiliary Sail course.
• First Aid & CPR Requirement: Only required when, in the opinion of the Coast Guard, the geographic area over which service is authorized precludes obtaining medical services within a reasonable time. Check the OCMI approval.
• Tonnage:The OCMI approval should have a specified tonnage, if not specified, calculate tonnage in accordance with 46 CFR 11.422.

(This is to satisfy the unique qualification requirements of an applicant or distinct group of mariners per 11.201(l))

• Must evaluate in accordance with OCMI approval – Example 360 days required for Master 50 GRT Inland reduced to 180 days by the OCMI. The MMC will have the OCMI specific approval such as to specific company, vessel type (DUKW), and/or body of water (Lake Arkansas) etc. The OCMI may only reduce sea service and examinations, all other general requirements such as 1st Aid/CPR, Medical Certificate, SSEB, and fees are required. When in doubt, pull the non- limited MMS (In the example above, the OCMI has reduced service and examinations for Master 100 Inland, so pull that MMS for all general information.) Exams as determined in the OCMI approval or course in lieu of.

USCG Limited OUPV Sea Service Requirements

(Formal Camps, Yacht Clubs, Educational Institutions, and Marinas)

• 90 days of service in the operation of the type of vessel specified for which the endorsement is requested; Recency per the OCMI approval; Complete a Safe Boating course; and Pass a limited exam.
• First Aid & CPR: Only required when, in the opinion of the Coast Guard, the geographic area over which service is authorized precludes obtaining medical services within a reasonable time. Check the OCMI approval.

(This is to satisfy the unique qualification requirements of an applicant or distinct group of mariners per 11.201(l))

• Must evaluate in accordance with OCMI approval – Example 360 days required for OUPV Inland reduced to 180 days by the OCMI. The MMC will have the OCMI specific approval such as to specific company, vessel type (DUKW), and/or body of water (Lake Arkansas) etc. The OCMI may only reduce sea service, age and examinations, all other general requirements such as 1st Aid/CPR, Medical Certificate, SSEB, and fees are required. When in doubt, pull the non- limited MMS (In the example above, the OCMI has reduced service and examinations for OUPV Inland, so pull that MMS for all general information.) Exams as determined in the OCMI approval or course in lieu of.

USCG Restricted OUPV Sea Service requirements

• 90 days of service in the operation of the type of vessel and on each body of water for which the endorsement is requested (Service on body of water may be reduced by OCMI); Recency per the OCMI approval; First Aid and CPR; and, Pass a limited exam.

USCG Master Unlimited GL and Inland License Requirements

• Recency: 90 days in the past 3 years on vessels of appropriate tonnage

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: 180 days of service as 1st Mate and 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.

Unlimited Tonnage

• All required service is on vessels 100 GRT or more, AND 50% of the required service on vessels 1600 GRT or more.

Tonnage Limitation

• A 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 and Advanced Fire Fighting Course
• Radar Observer - Required if your service started after March 24, 2014 – 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: 90 days in the past 3 years on vessels of appropriate tonnage. 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 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

Other Requirements

• First Aid
• CPR
• Approved Basic and Advanced Fire Fighting Course
• Radar Observer - Required if your service started after March 24, 2014 - May use expired certificate for RIG but RADAR will not be endorsed on the MMC if expired.

National Master 200 Ton GL and Inland License Requirements

• Recency of Sea Service: 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 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

• 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 100 Ton GL and Inland License Requirements

• Seagoing Recency: 90 days in the past 3 years on vessels - Experience gained in the engine department on vessels of appropriate tonnage may be creditable for up to 90 days of the service requirements

Master Less Than 100 Sea Service Requirements

• Great Lakes: 360 total days of service in the deck department, OF WHICH 90 days of service on Great Lakes, otherwise the endorsement will be limited to inland waters of the United States (excluding the Great Lakes)
• Inland: 360 days of service on any waters

Sail or Auxiliary Sail Endorsement

• 180 days on sail or auxiliary sail vessels
• Complete CG exams or approved course

Commercial Assistance Towing Endorsement

• Complete CG exams or Approved course

Other Requirements

• First Aid
• CPR

USCG Master of Towing OC, NC, GL-IN, WR License Requirements

• Recency oof sea Service: 90 days service in the past 3 years on vessels. A minimum tonnage is not applicable for towing MMC.
• Note: Service towards an Oceans, NC endorsement will be credited as  - Service on GL will be credited day for day; Service on inland waters, other than GL, may substitute for up to 50% of the total required service; Only service on WR is applicable towards WR endorsement; and The OC or NC TOAR must still be completed to obtain the OC or NC endorsement.
• Master of Towing Vessels Sea service Requirements: 540 days must be on towing vessels as Mate (Pilot) AND 90 days must be on a particular route.
• Holds Inspected Master More Than 200 GRT: May operate towing vessels within any restrictions on their endorsement if they have  30 days of training & observation on towing vessels on a particular route; AND Either hold a completed TOAR OR complete an approved course.
• Note: Western Rivers requires 90 days of observation and training, TOAR or approved course and must be endorsed on credential; EXCEPTION -If operating on LMR Pilotage waters (MM 236 and below), not required to hold WR endorsement but must hold Master of T/V for other routes/waters.
• Remove Tonnage Limitation:  For mariners who were grandfathered with tonnage to match the inspected deck officer endorsement (Example: Master 100 GRT inspected with Master T/V 100 GRT). Not to be used for limited geographic endorsements. Completion of Apprentice Mate (Steersman) Exam or course, route appropriate.
• Note: There is no equivalent or superior exam to remove the tonnage limitation on the T/V Endorsement. The equivalent or superior exam only applies to those who have never held Master of T/V and have met grandfathering per NVIC 3-16, Enclosure(10)

Requirements for Adding a Route

Other Requirements

• Note: 11.463 (f) Deck officers serving on the following seagoing vessels must hold the appropriate STCW endorsement -  A towing vessel on an oceans voyage operating beyond near-coastal waters; A towing vessel on an international voyage; A towing vessel of 200 GRT or more on a domestic, near-coastal voyage.

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

• Recency of Seagoing: 90 days in the past 3 years on vessels of appropriate tonnage

Master OSV Less Than (<) 1600 /3000 GT ><)1600 /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 2. 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 (>) 1600/3000 GT (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 (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 be placed on the officer endorsement)

Master OSV valid on Tank Vessels

• Meet requirements for Master OSV 10,000 GRT / 10,000 GT. And 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 Advanced Fire Fighting Course

USCG Master OSV Restricted to Liftboats License Requirements

• Sea Service Recency: 90 days in the past 3 years on vessels of appropriate tonnage
• Master OSV Less Than (<) 1600 /3000 GT Restricted to Service on Liftboats(<)1600 /3000 GT Restricted to Service on Liftboats Sea Service: 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).
• Master OSV 1600/3000 GT or More (Not To Exceed 10,000GRT/GT) Sea service: 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.
• 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/GT WHICHEVER IS GREATER. Tonnage limitation on endorsement must not exceed 10,000 GRT/GT

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

Other Requirements

• Approved Advanced Fire Fighting Course

USCG Examinations

• USCG Examinations
• USCG Engine Exam Study Materials

LAST UPDATED ON June 02, 2018