The South African Navy has a strength of 6,104 active military personnel. The navy is divided into a Combat Fleet and a Support Fleet. The Combat Fleet is made up of five Valour-class frigates, three Heroine-class submarines, three Warrior-class patrol vessels, three T-class patrol vessels, three River-class mine countermeasures vessels, and twenty-one Namacurra-class harbour patrol boats. The Support Fleet is made up of one replenishment vessel, one Hecla-class survey vessel, and three tugboats. The navy also includes an infantry-trained special forces unit called the Maritime Reaction Squadron (MRS).