A sea service day is at least four hours underway on a vessel under 100 gross registered tons (GRT), per 46 CFR 10.107. You need a minimum of 360 days to qualify for an OUPV/Six-Pack or Master captain’s license, with 90 of those days falling within the seven years before you apply. You document each day on Coast Guard Form CG-719S, the Small Vessel Sea Service Form.
Sea service trips up more aspiring captains than any other part of the licensing process. Not because the time is hard to get, but because the rules around what counts, how it’s measured, and how you prove it catch people off guard. One wrong detail and your application stalls at the National Maritime Center (NMC), the office that reviews all captain’s license applications.
We’ve helped more than 200,000 students work through this process. Here’s what you need to know to get it right.
The United States Coast Guard (USCG) defines one day of sea service as at least four hours underway on a vessel under 100 GRT, per a federal regulation known as 46 CFR 10.107. On vessels 100 GRT and above, a day requires eight hours of watchstanding or day-working. You can only claim one day per calendar year, no matter how many hours you log or how many boats you ride.
The vessel you use must have at least a 5-horsepower engine and cannot exceed 200 GRT. Sailing vessels qualify if they carry at least a 5-horsepower engine aboard, but you don’t have to use it. Without a motor on board at all, only 20% of that time counts toward your total.
Your time on the water has to involve operating or crewing the vessel. The Coast Guard wants proof you can handle a boat and the people on it.
The total depends on the type of captain’s license you’re after and the waters you plan to operate on.
|
License |
Total Days |
Route-Specific Requirement |
Recency (Per NMC Checklist) |
|
OUPV/Six-Pack Inland |
360 |
None |
90 days in the past 7 years |
|
OUPV/Six-Pack Near Coastal |
360 |
90 days seaward of the Boundary Line |
90 days in the past 7 years |
|
Master Inland |
360 |
None |
90 days in the past 7 years |
|
Master Near Coastal |
720 |
360 days seaward of the Boundary Line |
90 days in the past 7 years |
For the Coast Guard’s math, one month equals 30 days and one year equals 360 days. The 360-day total is a lifetime accumulation going back to your 16th birthday. The 90-day recency requirement is the piece people most often miss.
Yes. About 80% of our students get their captain’s license for personal knowledge and safety rather than immediate commercial use, and most build their sea service on recreational vessels. Time on your own boat, a friend’s boat, a rental, or a boat-club vessel all counts, as long as you were operating or actively crewing and you can document it.
Our guide to how to get sea time without owning a boat walks through most scenarios.
You don’t need a commercial job to reach 360 days. Most of our students piece together their time from a mix of recreational boating, charter work, and club memberships. Here are the most common paths.
If you own a boat, every trip of four hours or more counts as a day. You sign your own CG-719S and attach proof of ownership: a title, state registration, Certificate of Documentation, insurance card, or bill of sale. This is the simplest path and the one most of our students use.
Working as a deckhand or crew member on charter boats, fishing vessels, or eco-tourism operations is one of the most direct ways to build sea service. The time you spend onboard counts as long as you’re performing duties related to vessel operations, not just along for the ride. These roles also give you a look at what you can do with a captain’s license.
Members of boat clubs and rental services can accumulate sea service on every qualifying trip. If you bareboat charter (rent a boat and operate it yourself), that time counts. Get the rental company or boat owner to sign your CG-719S or provide a letter on company letterhead.
Many local boating clubs and maritime organizations offer crew opportunities. By volunteering, you accumulate sea service days while working alongside licensed professionals. The time counts the same as paid work, as long as you’re performing operational duties.
Some experienced captains and maritime organizations offer structured mentorship programs. These programs pair you with a licensed captain for hands-on training and help you build documented sea service. Reach out to local marinas or contact companies in your area.
Veterans and active service members can apply military sea time toward a captain’s license, but the Coast Guard credits it at 60% of each qualifying day. A hundred days at sea in a qualifying role yields 60 days of credit.
Your duties must have directly involved operating or steering the vessel, and you’ll need official documentation: a sea service transcript, certified history of assignments, or certified statement of creditable service. Our guide on using military experience as sea service covers the details.
Proper documentation is the difference between an application that moves forward and one that stalls for months at the NMC. The Small Vessel Sea Service Form CG-719S is the standard form for vessels under 200 GRT.
Fill out one form per vessel. The form is laid out like a calendar: twelve columns for months and five rows for years.
Estimate the number of days you were underway in each month as accurately as you can recall. Each form covers up to five years of experience on a single vessel.
|
Documentation Scenario |
What You Need |
|
Your Own Boat |
Signed CG-719S + proof of ownership (title, registration, insurance, or bill of sale) |
|
Friend’s or Family Boat |
CG-719S signed by the boat owner |
|
Employer’s Boat |
CG-719S or sea service letter on company letterhead |
|
Boat Club or Rental |
CG-719S signed by the club or rental company |
|
Military Vessel |
Official sea service transcript or certified statement |
Keep copies of every record you submit. You’re responsible for backing up your own claims.
The number one mistake we see is waiting too long to start documenting. Reconstructing years of boating history takes longer than people expect, and tracking down a former employer or boat owner for a signature takes longer still.
Other common errors include adding up experience incorrectly, counting more than one day per 24-hour period, using time on a vessel without at least a 5-horsepower engine, and mixing up the recency window. Your 360 total days never expire, but 90 of those days must fall within the seven years before you submit your application packet.
Yes. Time on foreign waters can count toward a Merchant Mariner Credential (MMC), the credential behind the captain’s license, when you document it properly. Crew or passenger time on a cruise ship doesn’t qualify, because those vessels sit in a different class and you’re treated as a passenger.
Every trip you take on the water is potential credit toward your captain’s license. The difference between a smooth application and a delayed one almost always comes down to documentation. Start filling out your CG-719S today, even if you’re years away from applying.
If you have questions about sea service or any other part of the captain’s license application requirements, the team at Mariners Learning System is here to help. We’ve guided more than 200,000 students through this process, and we’re not going to let paperwork be the reason you don’t get your license.
This article is for informational purposes and does not constitute legal or regulatory advice. USCG requirements change. Confirm current requirements with the National Maritime Center before submitting your application. Reviewed for accuracy against current USCG guidance by the Mariners Learning System team.
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