Walrus-class

The Walrus-class submarine is a diesel-electric attack submarine class operated by the Royal Netherlands Navy of the Netherlands. In 1974, the Dutch Ministry of Defence announced plans in the Defensienota 1974 to replace the aging Dolfijn-class submarines. Jan Jaap van Rijn, Chief Bureau of Submarines at the Directorate of Materiel, designed the class. On 19 June 1979, the Minister of Defense signed a contract with Rotterdamsche Droogdok Maatschappij (RDM) to build the first two vessels. HNLMS Walrus was laid down in 1979, followed by HNLMS Zeeleeuw in 1981. Following the 1983 bankruptcy of RDM's parent company, the navy ordered two additional vessels early to assist the shipbuilder financially. Technical challenges and a major command center fire aboard HNLMS Walrus in 1986 delayed construction, resulting in HNLMS Zeeleeuw entering service first in 1990. HNLMS Walrus was commissioned in 1992, followed by HNLMS Dolfijn and HNLMS Bruinvis.

The hull of the Walrus-class submarine is constructed from elastic French-produced steel to allow deeper diving depths. For propulsion, the boats utilize SEMT Pielstick PA4 200 VG diesel engines, a HOLEC electric motor, and VARTA batteries driving a single five-blade shaft. The class features an "X" tail configuration that combines four rudders and diving planes. Subsurface sensors include the Thomson Sintra TSM 2272 Eledone Octopus sonar, GEC Avionics Type 2026 towed array, and Thomson Sintra DUUX 5 passive ranging sonar, while surface sensors include Signaal/Decca 1229 and Signaal ZW-07 radars. Weapons are integrated through the HSA GIPSY combat system and fired from four 21-inch torpedo tubes. The armament includes Honeywell Mark 48 or Mark 37 torpedoes, UGM-84 Harpoon surface-to-surface missiles, and up to 40 mines. Under the IP-W Conservation Program initiated in 2013, the submarines were upgraded with Mark 48 Mod 7 torpedoes, an L-3 KEO optronic mast, a mine and obstacle avoidance sonar, and an updated combat management system.

Designed to hunt Soviet submarines during the Cold War, the Walrus-class submarines have been deployed for intelligence-gathering operations in the North Atlantic, the Mediterranean, the Persian Gulf, and the Caribbean. The Royal Netherlands Navy used the class to enforce international sanctions during the Yugoslav Wars, and deployed a submarine in 2010 to combat piracy off the coast of Somalia. In November 2016, the Russian Navy claimed to have chased off a Walrus-class submarine from a battle group led by the aircraft carrier Admiral Kuznetsov. The class is also utilized to host the Submarine Command Course for Dutch, British, Australian, and Canadian candidates. HNLMS Walrus was decommissioned in October 2023, and the remaining active submarines are scheduled for replacement by the Naval Group-designed Orka class in the 2030s.