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HMS Ocean (L12)

Amphibious Assault Vessel / Landing Helicopter Platform

Naval Warfare / Ships

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Image from the United States Department of Defense imagery database.
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Image from the United States Department of Defense imagery database.
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Image from the United States Department of Defense imagery database.

HMS Ocean is currently under active status with the British Royal Navy and is the only ship in her class.

Authored By: Staff Writer | Last Edited: 12/10/2020 | Content ©www.MilitaryFactory.com
Modern navies of Europe rely more on amphibious assault support/helicopter carrier types than true dedicated flat-top deck aircraft carriers. The British Royal Navy has made use of such vessels as exemplified by its HMS OCean (L12). The ship became a conventionally-powered vessel serving as many as eighteen helicopter of various lift-class types including medium and heavy designs. Ordered on May 11th, 1993, the vessel was laid down by Vickers Shipbuilding and Engineering Limited of Kvaerner, Scotland on May 30th, 1994 and launched on October 11th, 1995. Commissioned on September 30th, 1998, she served the British crown, making her homeport out of HMNB Devonport of Plymouth, until being decommissioned in 2014. She fought under the motto of "The Mighty O".

As completed, Ocean displaced at 23,700 short tons and features a length of 667 feet, a beam of 115 feet, and a draught of 21 feet. Her propulsion machinery consisted of 2 x Crossley Pielstick V12 diesel-fueled engines which allow for speeds of up to 18 knots on full throttle while cruising is typically in the 15 knot range. Operational range reached up to 8,000 miles with a full fuel and food stores load. Her complement numbered 285 personnel with 180 additional crew making up her air arm. Her processing suites and sensor equipment were all-modern for her time to counter various inbound threats. This included the Type 997 Artisan 3D radar offering full situational awareness, navigational, and target indication capabilities and 1007 and 1008 radar sets as well as a UAT countermeasures suite.

Armament was largely light and defensive in nature for her true role was always in support of her flight wing and amphibious operations. As such, armament was limited to 4 x 30mm DS30M Mk 2 series cannons, 3 x 20mm Phalanx Close-In Weapon Systems (CIWSs), 4 x miniguns, and up to 8 x 7.62mm General Purpose Machine Guns (GPMGs). In this way, Ocean could counter incoming aircraft and missile threats as well as suicide boats attempting to reach her sides.

Her air wing would number as many as eighteen rotary-wing aircraft with full support of Sea King, Lynx, Wildcat, and Merlin medium-lift types as well as proven heavy-lift models like the CH-47 Chinook tandem-rotor transport. Additionally, the vessel supported the launching and retrieval of AgustaWestland "Apache" attack helicopters - the British Army equivalent of the American Army's AH-64D "Apache Longbow".

For amphibious support operations, Ocean's hold could transport up to 40 military vehicles and 830 combat-ready Royal Marine elements with troops brought ashore either through transport helicopters or by way of four LCVPs ("Landing Craft Vehicle Personnel") carried. Alternatively, HMS Ocean could be put to use in support of humanitarian initiatives which could require the mass movement of people. Onboard healthcare facilities were used to treat any wounded or sick prior to delivery to a land-based facility.
Her overall external arrangement was largely modeled as a conventional aircraft carrier design though she did not support the landing and take-off of large, fixed-wing aircraft as common to American aircraft carriers. Her bridge island superstructure - containing all necessary communication and sensory equipment was set to the starboard side of the vessel in the typical fashion. This opened the bow, stern, and portside to be used as a staging area for landing and releasing the helicopter component. Launch ports were also featured along the sides of the ship for its stock of amphibious landing craft.

HMS Ocean's first actions were in humanitarian relief missions off the coast of Honduras and Nicaragua following Hurricane Mitch in late 1998. She then served as part of Operation Palliser against rebel forces in Sierra Leone. During the 2003 U.S.-led invasion of Iraq, HMS Ocean launched her assault helicopters in support of various operations. During 2007, she entered refit at the Devonport Royal Dockyard and several joint multinational exercises then followed. With the 2010 eruption of Eyjafjallajokull. Ocean used her retrieval capabilities to rescue personnel across the English Channel - the volcano crippling all manner of travel across northwestern Europe. During the 2012 London Olympic games, HMS Ocean stood on standby in the event her facilities and aircraft would be needed to respond to an Islamic terrorist attack.

In 2014, HMS Ocean underwent a seven-month period of major refitting which saw some 60 systems upgraded for broadened capabilities. She has also taken part in joint exercises with the French and supported several training initiatives. The Royal Navy also now awaits two more modern flat-top deck carriers in the HMS Queen Elizabeth (R08) and HMS Prince of Wales (R09) which are undergoing construction as of this writing (2014).

March 2018 - HMS Ocean was formally decommissioned from service with the Royal Navy.

June 2018 - HMS Ocean has been formally commissioned for service in the Brazilian Navy fleet as BNS Atlantico where she is to serve as flag ship.


Decommissioned, Out-of-Service
1,300 Personnel
Ship Class [ Ocean-class ]
Ships-in-Class [ 1 ] Ship Names: HMS Ocean (R12) (BNS Atlantico - Brazilian Navy since 2018)
National flag of United Kingdom United Kingdom
- Aircraft / Offshore Support
- Amphibious Operations Support
- Blue Water Operations
- Fleet Support
- Hunter
- Direct-Attack
667 ft (203.30 m)
Width / Beam:
115 ft (35.05 m)
Height / Draught:
21 ft (6.40 m)
Displacement (Surface):
23,700 tons
2 x Crossley Pielstick diesel engines with 1 x Kamewa bow thruster (since removed) driving 2 x Shafts astern.
Speed (Surface):
18 kts (21 mph)
6,952 nm (8,000 miles; 12,875 km)
4 x 30mm DS30M Mk 2 Autocannons.
3 x 20mm Phalanx Close-In Weapon System (CIWS).
4 x 7.62mm M134 Miniguns.
8 x 7.62mm General Purpose Machine Guns (GPMGs).
18 x Helicopters of various types (Westland Apache, Westland Lynx, Boeing Chinook and similar). These can be replaced by VTOL-types such as 15 x BAe Harrier II jump jets.

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