The Rates

¹⁾ I am using the classic classifications by Landström and zu Mondfeld. According to Wikipedia, frigates with 28 guns were also downgraded to sixth rank, probably towards the end of the 18th century.

^Rem.) If sixth-rate ships sailed into battle, it would have been shortly after the six-rate rating system was introduced in the early 17t^h century. I did some more research for these data sheets. Going back well into the 17^th century, I could only find descriptions of ships with one battery deck. However, I found no two-deckers that could be considered ships of the line, like the 5^th-rate ships.

However, I found a 3D illustration of a sixth-rate ship from 1697. This shows that the development of the ‘modern’ frigate had begun by the end of the 17^th century.

The HMS Seahorse, whose rebuild in the 1770s inspired the illustration above, represents the final stage of this development. However, 24-gun 6^th rates were no longer permitted to be called frigates after 1750. (Instead, the term ‘postship’ became established.)