third-rate

Short definition from Wiktionary

Adjective

1. 1
   Of a Royal Navy ship of the line in the Napoleonic Era: having 64–80 guns across two gun decks, a complement of 500–650, and weighing approximately 1,750 tons burthen.
2. 2
   Poor, shoddy; less than second-rate.
3. 3
   Alternative spelling of third-rate.

Noun

1. 1
   A third-rate ship of the line.
2. 2
   Alternative spelling of third-rate.