A collection of more than a quarter of a million maritime examination records signalling the end of the stereotypical "drunken" and disorderly sailor go online today.
The Great Britain, Masters and Mates Certificates, 1850-1927, which will be available on the family history website Ancestry.co.uk, comprise 280,000 records showing how behaviour of sailors in the Merchant Navy was regulated.
The documents, released in partnership with the National Maritime Museum, detail the seamen who passed examinations designed to test their experience and general good conduct, and give evidence of their sobriety.
The Masters Certificatre awarded to Edward John Smith, the captain of the ill-fated Titanic
The system aimed to combat drunk and disorderly behaviour, which was rife in the Merchant Navy during the early 19th century.
Upon passing, men were awarded a Masters Certificate as proof that they were fit for service. Certificates specified the recipient's name, address, certificate number, birth date, birth place, port of issue, examination date and the previous ships on which they sailed.
It was the Mercantile Maritime Act of 1850 that led to the introduction of Masters Certificates by the British Board of Trade and all ranks, from mates to captains, were required to sit these examinations.
After the new law was introduced in 1850, disorderly sailors were quickly forced to clean up their act. Crucially, legislation stated that seamen were no longer permitted to "sell bad drugs", "work under the influence of alcohol" or "fraudulently alter" their Masters Certificates.
Ancestry.co.uk international content director Miriam Silverman said: "These records provide fascinating insight into Merchant Navy life at the turn of the 19th century and signal the end of the stereotypical 'drunken' and disorderly sailor. They also went a long way to helping the Merchant Navy become respected the world over.
"They are also a rich source of information for anybody looking to find out more about a seafaring relative, or trace the career of a famous captain."
Some famous examples of captains who managed to successfully pass their examinations include:
Edward John Smith - he captained the ill-fated Titanic on its maiden voyage in 1912. He received his Masters Certificate in February 1888.
Captain George Moodie - Master of the renowned British tea clipper the Cutty Sark, he was awarded his certificate in Fife in 1861 before captaining numerous voyages to India.
Sir Edgar Britten - despite running away to sea aged 15, he qualified as a Master in December 1900 and went on to captain the RMS Queen Mary, a large ocean liner that was later used as a troopship carrying Australian soldiers to the UK.