Why Royal Navy second rates disappeared from the active list

What happened to the apparent loss of two second rates between 1794 and 1814, and were sixth rates separate from post ships?

Sixth rates were post ships, while most of the apparent second-rate decline came from counting ships in commission: the Navy preferred better-sailing first rates and retained many other hulls in ordinary rather than losing them outright.

Sixth rates were post ships: command of any rated vessel was formally posted, though the smallest rated ships were usually called post ships because they were too small to be frigates. The table counted commissioned ships, not every hull owned by the Royal Navy, and one second rate was lost during the period. Three-deck second rates were comparatively short and tall, making them less stable and less satisfactory sailors than the longer first rates, so the Navy often commissioned a first rate such as Victory when it had a choice. Many other ships remained "in ordinary," including captured Danish, Dutch, Spanish, and French vessels that could serve as reserves, hulks, or sources for later repair. Some nominal reserve hulls were no longer practical to reactivate, but the total still represented considerable depth. This distinction explains why manpower, rather than hull availability alone, often constrained British fleet strength.