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Coastal Patrol, Offshore Patrol, and Maritime Defence  –  September 2004

Maritime Security:  Offshore Patrol Vessels – Specifications

Thetis-class Hvidbjoernen - Orlogsmuseet photo Comparing Frigate-sized OPVs
Here we compare specifications for the Halifax-class frigate with three roughly equivalent OPVs. (The much greater weight of the Canadian ship can be attributed to its emphasis on ASW which requires more weapons & crew than will an OPV's patrol duty.)

Class Length Weight Speed Crew Main Gun Helicopter
Halifax 134m 4750t 30kts 215  57mm L/70 Sea King
Thetis [1] 122m 3500t 25kts 61+ 76mm L/62 Sea Lynx
Nordkapp 105m 3420t n/a 52+ 57mm L/70 Sea Lynx
Yarrow [2] 95m 1940t 30 kts 39+ 76mm L/62 SeaHawk

[1] The Thetis-class is derived from a Standard Flex 3000 design. If these vessels were equipped as StanFlex frigates, the weight would be closer to a Halifax-class.
[2]  Specifications are based Brunei's heavily-armed Nakhoda Ragam-class OPVs.

Aegir & Tyr - Icelandic Coast Guard photo Corvette-Sized  (and Smaller)  OPVs
Many of the smaller OPVs were begun as commercial ventures as opposed to responses to a domestic requirement. As such,  armament fittings may differ from the exact calibres or types listed. For the same reason, most helicopters are listed by weight-class, not model.

Class Length Weight Speed Crew Main Gun Helicopter
MEKO 100 91m 1600t 23kts 62+ 76mm L/62 16t class [1]
Castle (UK) 81m 1427t 18kts 42+ 30mm auto Sea King [2]
Eithne (Ir) 80m 1970t 19kts 86 57mm L/70 Dauphin
Róisín (Ir) 79m 1700t 22kts 50 76mm L/62 [ none ]
River (UK) 79m 1677t 16kts 30 20mm KAA Sea Lynx [2]
Vigilant 75m 1650t 20kts 57 40mm L/70 5t class
Visby (Se) 73m 600t 38kts 43 57 + 40mm 5t class
Ægir (Is) 70m 1500t n/a 19+ 40mm L/70 3-5t class [3]
Emer (Ir) 65m 1020t n/a 47 40mm L/60 [ none ]
Armidale 57m 270t 25kts 21+ 25mm M252 [ none ]
Kingston 55m 970t 15kts 31+ 40mm L/60 [ none ]

[1] The MEKO 100 is designed to accommodate the very largest naval helicopters. By contrast, the larger Halifax-class will require hangar modications for its CH-148.
[2]  Castle and River classes both have helicopter decks but neither have hangars.
[3] Ægir, Týr and Óðinn also have landing decks but lack hangars. Iceland's Coast Guard has both Ecureuil and Dauphin helicopters but they are based at Reykjavik.