If you’re aspiring to join the merchant navy, understanding the concept of "sea time" is crucial. While it may sound like simply the time seafarers spend at sea, it specifically refers to the time spent actively working on a vessel—an essential metric for career advancement in the maritime industry.
Whether you aim to work on merchant ships or rise through the ranks of the merchant navy, sea time is a cornerstone of your professional journey.
If you want to learn more about sea time, you’ve come to the right place.
What is sea time?
Sea time is the duration seafarers spend performing their duties aboard a ship that is actively sailing for cargo transportation.
Sea time requirements for seafarers may vary from one country to another because it depends on the minimum qualification criteria that is determined according to the Standards of Training, Certification and Watchkeeping for Seafarers (STCW) 2010 guidelines.
Sea time is the document that the department head – a chief engineer or the ship’s master (the captain) – hands to the seafarer that confirms their presence onboard the vessel and stating that they have sailed for a specific period of time. The sea time certificate also covers remarks on conduct and the professionalism of the seafarer while onboard.
Key Details Included in a Sea Time Certificate:
- Name and official number of the ship
- Gross tonnage (GT) of the vessel
- Date of service (from sign on to sign off)
- Engine type and specifications, including horsepower
- Total number of days worked, categorized as coastal, inland, or river waterways
- Description of duties performed onboard
- Watchkeeping responsibilities
- Average number of hours worked per day (minimum of 8 hours)
- Remarks on conduct and professionalism
The sea time certificate must bear the ship’s official seal and the master’s signature to be considered valid. Retaining all your certificates is essential, as they are required for Certificate of Competency (COC) exams, whether you’re aiming to become a deck officer or an engineering officer.
Importance of sea time in a seafarer's career
Sea time is pivotal in determining promotions and professional growth within the merchant navy or other maritime organizations. To qualify for higher ranks, seafarers must meet specific sea time requirements aligned with their COC and the Standards of Training, Certification, and Watchkeeping (STCW) 2010 guidelines. Merchant navy jobs operate under a strict chain of command that will remain the same regardless of shipping company or ship.
Why sea time matters
- Promotion criteria: Shipping companies use a Company Matrix System to evaluate candidates for promotions, requiring specified sea time for each rank.
- Job switching: If switching companies, sea time certificates provide verifiable proof of experience.
Examples of rank progression
Rank: Deck Officer
Required sea time: 12 months
Additional notes: Includes watchkeeping duties
Rank: Third Officer
Required sea time: 36 months
Additional notes: Requires passing COC exams
Rank: Engineering Officer
Required sea time: 24 months
Additional notes: Includes engine operation records
Sea time and merchant ships
Sea time requirements can vary significantly depending on the type and size of merchant ships you work on. Larger vessels, such as those with higher gross tonnage (GT) or specialized engineering systems, may provide more comprehensive experience for advancing as an engineering officer or deck officer. Working on a variety of vessel types—from bulk carriers to container ships—can broaden your skill set and improve your employability.
How is sea time calculated?
Sea time calculations can vary by country and shipping company policies. It typically starts on the date the ship’s master stamps the seafarer’s document confirming their role onboard.
Points to Consider:
- Dry dock periods: Time spent while the ship is docked or laid up is valid if the period is less than two months.
- Work hours: A full day of sea time requires at least eight hours of assigned or watchkeeping duties.
- Variations by country: Some nations calculate sea time in days, while others measure it in months, depending on local maritime regulations and the requirements for COC qualifications.
Take note that a day of work requires eight hours of assigned or watchkeeping duties.
Role of sea time in world wars
During World War II, the concept of sea time became critical in assessing the readiness and experience of seafarers serving on merchant ships that supported Allied operations. These vessels, which carried essential supplies, faced immense challenges, including enemy attacks.
The introduction of formalized sea time documentation allowed for better training and deployment of deck officers and engineering officers, ensuring the reliability of the merchant fleet in 24-hour wartime operations.
Tips for aspiring seafarers
- Track your sea time regularly: Keep all sea time certificates well-organized and up-to-date.
- Aim for higher ranks: Plan your career path by understanding the sea time requirements for deck and engineering officers.
- Understand merchant ship metrics: Familiarize yourself with terms like gross tonnage (GT), which influence ship classification and seafarer responsibilities.
- Work across vessel types: Gaining experience on different merchant ships broadens career opportunities.
- Meet certification requirements: Stay updated on STCW guidelines and ensure your sea time aligns with these standards.
Example: Daily life onboard
Working onboard a ship involves long hours, typically in 24-hour shifts, with responsibilities divided between deck officers and engineering officers:
Deck Officers:
- Oversee cargo operations
- Navigate and monitor the vessel’s position
- Conduct safety drills and inspections
Engineering Officers:
- Maintain and repair ship engines
- Manage fuel consumption
- Oversee onboard electrical systems
This division of duties highlights the importance of specialization and the critical role sea time plays in refining these skills.
What you need to know about sea time: conclusion
Sea time is more than just a professional requirement; it’s the cornerstone of a successful seafaring career. From joining a merchant fleet to advancing as a deck officer or engineering officer, maintaining accurate records of your sea time ensures career progression. Understanding key metrics like gross tonnage (GT) and gaining experience on a variety of merchant ships can further enhance your employability.
Meanwhile, if you’re looking for your next contract in your seafarer career, we can help. Don’t hesitate to visit our website and create an account so that you can start applying for our seafarer job vacancies.
And for more maritime information, visit our blogs and like and follow us on Facebook, Twitter/X, and LinkedIn.
This blog post was originally written on November 21st 2022 and updated on December 17th 2024.
Nathaly Seruela
Former content writer at Martide.
Guest Blogger
A varied collection of articles about the maritime industry written for Martide by various guest bloggers from their own unique perspectives. These include posts by a professional chef who works on container ships and other people connected to, or interested in, shipping and life at sea.
is the only site for maritime jobs
