HMS Colchester was a 50-gun fourth rate ship of the line

Ship of the line

A ship of the line was a type of naval warship constructed from the 17th through the mid-19th century to take part in the naval tactic known as the line of battle, in which two columns of opposing warships would manoeuvre to bring the greatest weight of broadside guns to bear...

 of the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

, built at Southampton

Southampton

Southampton is the largest city in the county of Hampshire on the south coast of England, and is situated south-west of London and north-west of Portsmouth. Southampton is a major port and the closest city to the New Forest...

 according to the dimensions laid down in the 1741 proposals of the 1719 Establishment

1719 Establishment

The 1719 Establishment was the first formal 'Establishment' laid down to govern the construction of all ships built or rebuilt down to those of 20 carriage guns, whether in the Royal Dockyards or by commercial contractors...

, and launched on 20 September 1745. She was ordered as a replacement for the previous , which had been wrecked just two months after being launched.

Colchester served until 1762, when she was found to be unfit for service. She was eventually broken up in 1773.