 Complete the following phrase:  On 16 September 1963, the naval force was renamed the Royal Malaysian Navy RMN, following the formation of Malaysia. Eighteen Keris-class were ordered from Vosper, and formed the mainstay of the navy for years to come. These boats were driven by Maybach diesels and capable of . The Keris patrol boats were confined to coastal patrols and had short endurance. An offensive capability was acquired with the purchase of four s also known as Perkasa-class patrol boats in RMN service. The Perkasa patrol boats were built for the RMN by Vosper Thorneycroft in 1967, powered by three Rolls Royce Marine Proteus gas turbines as the main power plant with two diesel auxiliary engines for cruising and manoeuvring. These were armed with four torpedoes, one Bofors 40 mm gun forward, and one 20 mm cannon aft. They had a maximum speed of and was driven by triple propellers. The Royal Navy transferred the to the RMN in 1964 and renamed KD Kapal Di-Raja, His Majestys Ship Hang Tuah. In 1965, during the 