A system of categorization used by the British Royal Navy to classify ships in order of their effectiveness in line of battle based primarily on their number of guns from the late 17th century until the beginning of the 19th.
See Ship of the Line and Frigate for more information.
Rating system, 18th century [ ]
Type
Rate
Guns
Decks
Examples in PotBS
Ship of the Line
1st
100 or more
4
'Invincible' First Rate , 'Prince' First Rate , 'Indomitable' First Rate , 'Victory' First Rate and 'Sovereign' First Rate .
2nd
82 to 98
4
'Trinity' Second Rate , 'Triumphant' Second Rate , 'Formidable' Second Rate , 'Sceptre' Second Rate and 'Terror' Pirate Second Rate .
3rd
62 to 80
3
'Valiant' Third Rate , 'Centurion' Third Rate , 'Lion' Third Rate , 'Wenden' Third Rate and 'Treason' Pirate Flagship .
4th
42 to 60
3
'Assistance' Fourth Rate , 'Trydent' Fourth Rate , 'Alexander' Fourth Rate , 'Mordaunt' Fourth Rate , 'Macedon' Hunter's Fourth Rate , 'Reason' Naval Fourth Rate , 'San Fernando' Fourth Rate , 'Santa Rosa' Privateer Fourth Rate , 'Poseidon' Fourth Rate and 'Hyperion' Refit Frigate .
Also: 'Abaddon's Will' Refit Galleon , 'Bahamut' Refit Bark , 'Concorde' Frigate , 'Couronne' Galleon , 'Marauder' Pirate Ship , 'Oliphant' Indiaman and San Mateo Galleon .
Frigate
5th
30 to 40
2
'Crocodile' Frigate , 'Cutlass' Frigate , 'Conquistador' Frigate , 'Myrmidon' Frigate , 'Hunter Frigate' , 'Santa Rita' Frigate , 'Defiant' Frigate , 'Deliverance' Frigate , 'Eagle' Frigate , 'Shark' Frigate , 'Viper' Frigate , 'Raa' Frigate , 'Assurance' Frigate , 'Atalanta' Frigate , 'Capricieux' Frigate , 'Rover' Frigate , 'Tigre' Frigate , 'Minerva' Frigate , 'Vengeance' Privateer Frigate , 'Adventure' Frigate , 'Hades' Frigate , 'Hercules' Frigate , 'Hector' Frigate , 'Mars' Frigate , 'Unity' Frigate and 'Vulcan' Frigate .
6th
20 to 28
1 -2
'Postillionen' Frigate , 'Cerberus' Frigate , 'Athena' Frigate , 'Hawk' Frigate , 'Wolf' Frigate , 'Peregrine' Frigate and 'Stralsund' Frigate .
Also: 'Agamemnon' Bark , 'Arcadia' Xebec , 'Batavia' Flute , 'Leviathan' Bark , 'Mignone' Indiaman , 'Reaper's Grasp' Refit Bark , 'Sampson' Flute , 'Sultan' Flute and 'Wager' Indiaman .
Sloop-of-war
Unrated
14 to 18
1
Algiers' Refit Polacre , 'Corsair' Xebec , 'Cruizer' Snow , 'Curieuse' Snow , 'Dromedary' Indiaman , 'Fallen' Refit Snow , 'Hermes' Packet-Boat , 'Lexington' Brig , 'Locust' Corvette , 'Mystique' Polacre , 'Nemea' Sloop-of-war and 'Santiago' Galleon .
Gun-brig or Cutter
6 to 12
1
All other ships. Particular low-level (1-15), trading (stripped versions) and/or non-combat ships.
This information is provided by the update that PotBS Wikia is undergoing, by Captain Vuur.