In May the Dutch Defense Ministry finalized plans and signed a contract to upgrade all four of the Royal Netherlands Navy’s Walrus -class submarines by 2019. The Zeeleeuw , second of the class, will be the first unit to complete the upgrades, which are to include installation of an advanced optronics mast in place of the current search/navigation periscope. Additional enhancements spelled out under the $120 million contract include satellite-communications and combat-management upgrades. Although designed during the final years of the Cold War, the Walrus class entered service in the early 1990s and has proven exceedingly valuable for intelligence collection and other 21st-century operations. Since 2010, some of the submarines have provided support to NATO counterpiracy operations off the Horn of Africa. Each of the 222-foot boats was built in Rotterdam and displaces 2,800 tons when submerged. All are fitted with four torpedo tubes.