AB to Third Mate

By Captain Mike · 50 years at sea · former MITAGS faculty
Requirements checked against NMC checklists and 46 CFR · October 2026

Before you file: Requirements and NMC policy change. Open the current NMC checklist linked at the bottom of this page and confirm every number against it.

The numbers that matter

3 yearsDeck department service on ocean self-propelled vessels (1,080 days) 46 CFR 11.407

6 monthsOf that, bridge watchkeeping under the supervision of the Master or a qualified officer, documented

100 / 1,600All service on vessels of 100 GRT or more; half on 1,600 GRT or more, or you get a tonnage limitation

Up to 3 months of engine department time on vessels of appropriate tonnage can count toward the total 46 CFR 11.407. Great Lakes time counts day for day. Inland time (other than the Great Lakes) counts day for day for up to half the total 46 CFR 10.232. On top of the service, you need the STCW Officer in Charge of a Navigational Watch competencies: approved training plus practical assessments signed off by a Designated Examiner 46 CFR 11.309.

Two ways to Third Mate

	Hawsepipe on your own	AB-to-Mate (Apprentice Mate) program
Required?	No. This is the standard route.	No. It's optional.
How it works	You build 3 years of deck service while working, and arrange your own courses and assessments.	A Coast Guard-approved program at a maritime school combines classroom training with structured sea time 46 CFR 11.407.
Speed	Slower. It depends on how often you sail and how much bridge time you can log.	Faster. The courses, assessments and sea time are planned for you.
Cost	You pay for courses one at a time, and you earn a paycheck while you go.	Tuition and fees, often with stretches of time away from paid work.
Getting in	Open to anyone with the required sea time.	You have to apply and be accepted.

Either way you take the same Coast Guard exam, and that exam also covers Second Mate. To see what comes after Third Mate, read The Deck Officer Ladder →

The hawsepipe path, step by step

Get your Able Seafarer first

AB (now called Able Seafarer) is the working foundation. Under the current rule, AB Unlimited requires 540 days of deck service on oceans or Great Lakes, and AB Limited requires 360 days on vessels of 100 GRT or more 46 CFR 12.403. If you've read "1,080 days for AB Unlimited" somewhere, that's the old figure: Congress made the shorter times permanent in December 2025, although the text of 46 CFR 12.403 hasn't caught up yet. AB, RFPNW & Able Seafarer-Deck →

Log bridge time separately from day one

The 6 months of supervised bridge watchkeeping is the requirement hawsepipers most often come up short on. Not because they didn't stand the watches, but because nobody wrote it down. Ask your company to state bridge watch days explicitly in every sea-service letter, and keep your own log that matches.

Track tonnage and waters vessel by vessel

Keep a running spreadsheet: vessel, official number, GRT, waters, days. Watch two ratios as you go. Is at least half your time on 1,600 GRT or more? Is inland time staying under half the total? Fixing either one late can cost you a year.

Build the training and assessment plan

Map every required course and every practical assessment against the checklist before you enroll in anything. Typical items include radar and ARPA, ECDIS, bridge resource management, GMDSS, advanced firefighting and medical first aid, but the NMC checklist is the authority on the exact set. Radar Observer → Advanced Fire Fighting → Get assessments signed while you're aboard vessels where you can actually perform them.

Prepare module by module

The Third Mate exam is several separate modules, not one test. Treat each as its own project with its own study block, and don't schedule the next until you're scoring comfortably on practice questions for the current one.

Audit before you submit

Lay every letter and discharge side by side against your spreadsheet. The evaluator should be able to find every day you're claiming, with vessel, tonnage, waters and capacity, without having to guess.

Traps that cost hawsepipers months

Bridge watch time that isn't on paper. Discharges showing "AB" don't prove bridge watchkeeping. If the letter doesn't say it, expect the evaluator not to count it.
Too much inland time. Inland service only covers up to half the total. Everything above that is dead weight on this application.
Short on big-ship time. Under half on 1,600 GRT or more means a tonnage-limited endorsement, not unlimited.
Claiming 1.5 days for 12-hour days. That credit only applies on vessels authorized to run a two-watch system 46 CFR 10.232. Letters that claim it anyway get cut back.
Assessments signed off in a hurry. An incomplete or unsigned Designated Examiner sign-off will stop an otherwise complete package.
An expired medical certificate. Check its date before you file, not after.

Two 2025 policy changes worth knowing

Recency is now 7 years. The regulation requires 90 days of service within the 3 years before a raise of grade, but CG-MMC Policy Letter 02-25 extended that window to 7 years. If you've been ashore for a few years, your older time may still count.

Master 500/1,600 holders may skip the exam. CG-MMC Policy Letter 01-25 removed the exam requirement for holders of Master 500 GRT or Master 1,600 GRT raising grade to Third Mate unlimited on the same route.

Application evidence

Item	What it has to show
Sea-service letters	Vessel, official number, GRT, waters, dates, capacity, and bridge watchkeeping days.
Discharges / company records	Corroboration of dates and capacity.
Course certificates	Every approved course the checklist requires, front and back copies.
Practical assessments	Complete, signed Designated Examiner sign-offs.
Medical certificate	Valid and unexpired, or a medical application submitted with the package.

Ready to apply? Applications now go through Navita, the Coast Guard's online credentialing system. It changes how you apply, not what you need. Navita: what changed →