Certificates of Competency for Merchant Navy Officers were dependent of time served at sea and an examination after months spent in a marine college. There were two different levels, foreign going and home trade. Home trade was around the UK coast, English Channel, North Sea and near continent. Foreign going was every where else in the world, when a sextant would be needed for ocean navigation.
The first certificate for all foreign going officers was a Second Mates, then a First Mate and eventually a Mater's Certificate. Between each certificate you would need to acquire more experience from time at sea then back to college. By the time I was issued my Master's certificate I had accumulated thirteen years of service, including leaves, and twenty four months in college.
As the offshore oil industry was fast expanding, there was a shortage of experienced officers and I was promoted to Master long before acquiring a Master's Certificate.
As international rules and regulations were improved and updated so the certificates were re-classified and re-titled. So my original Master Foreign Going became Class 1 Master Mariner, then a STCW 1995 Master Mariner, then an updated version of the previous one.
On the strength of my British certificates I was issued other Master's Certificates by the flag state when sailing on ships of that state. These were Panama, Vanuatu and Cayman Islands.
Master Foreign Going
STCW 1995 Master
STCW 1995 Master Updated