Deck officer licensing on 19th century merchant ships?

How would one go about becoming a deck officer (specifically first mate, though I assume other ranks worked similarly) in early- to mid-19th century Britain? Wikipedia has quite a bit of information on the modern licensing system in the USA, but very little on the UK and nothing at all pre-20th century.

I going to try remember class from old.

I do not believe there was liciencing in the early 1800’s.

On the engineering side it did not happen until there were many river boat disasters. Generally caused because safety was being disregarded to make the boats go faster. Gaging safeties, increasing boiler pressure and other things. The original liciences were issued by the commerce department, now they are issued by the US Coast Guard.