I programme and the British Type 15 frigates converted from fleet destroyers. Russia also used cruise missiles launched from corvettes, frigates, and Kilo-class submarines. However, the once distinct roles and appearances of cruisers, destroyers, frigates, and corvettes have blurred. Venezuela ordered six "Lupo"-class frigates from CNR in 1975 as a replacement for older warships. The purchase of 20 submarines, 35 corvettes and 15 frigates is planned. The base also houses training facilities for the frigates and submarines. Their forces are an assortment of TEC frigates, cruisers and defensive structures. The 1840s saw the construction of experimental steam-powered frigates and sloops. "Donghae"/"Pohang"-class corvettes with new 2,300-ton frigates. The purchases of s, the "Astute"-class submarines, and the Type 26 frigates were all confirmed. The Pakistani Navy carries the Harpoon missile on its frigates and P-3C Orions. G Super Seasprite helicopters for the two frigates. In 1887 Caprivi requested the construction of ten armoured frigates. A prominent addition to the fleet were two "Lekiu" class frigates. They replace older patrol craft and some of the Type 053H frigates.