As an island nation, the navy plays an important role in protecting the territorial integrity and security of Indonesia
With a large fleet, strong firepower, the Indonesian Navy is developing into a naval force of size in the region
Regarding frigates, in addition to two modern Martadinata-class frigates, the Indonesian Navy is operating five Ahmad Yani-class frigates
which were Van Speijk-class sold by the Royal Netherlands Navy to Indonesia in the 1980s
The Ahmad Yani-class originally consisted of six frigates, the KRI Slamet Riyadi (352) was retired in August 2019
The class was a license-built version of the British Leander class for the Royal Netherlands Navy in the 1960s
In the Indo Navy, the class was renamed the Ahmad Yani-class, with the lead ship being KRI Ahmad Yani (351)
The class was named after General Ahmad Yani, one of Indonesia's Revolutionary Heroes
Ahmad Yani-class has a full load displacement of about 2,850 tons, a length of 113.4 m, a beam of 12.5 m, and a draft of 5.8 m
Its propulsion system is two Caterpillar 3616 engines, producing 16,000 horsepower
The ship can reach a top speed of 28.5 knots, with a range of 4,500 nmi at 12 knots
The crew is 180 sailors
Ahmad Yani-class operates as a patrol fleet with anti-surface, anti-submarine and anti-aircraft capabilities
These include: 8 Chinese C-802 Surface-to-surface missiles with a maximum range of 120 km (70 nautical miles)
a speed of mach 0.9, guided active radar homing with a warhead weighing 165 kg
4 Mistral surface-to-air missiles in twin Simbad launchers for anti-aircraft defense
Effective range of 4 km (2.2 nautical miles), infrared guided with 3 kg warhead, capable of anti-aircraft, helicopter and missile
Particularly the KRI Oswald Siahaan 354, after being refitted, she was equipped with Russian SS-N-26 Yakhont surface-to-surface missiles
Other weapons include: 1 OTO Melara 76 mm gun with a rate of fire of 85 rpm, range of 16 km for surface targets and 12 km for air targets
There are 2 x 12.7 mm machine guns, 6 Mk 32 anti-submarine torpedo tubes with a range of 11 km at a speed of 40 knots and a warhead of 44 kg
Helipad and hangar support for 1 NBO-105C helicopter
Serving in the Indonesian Navy since 1986, the Ahmad Yani-class has actively participated in Indonesia's maritime security protection activities
In 1992, KRI Ki Hajar Dewantara, along with KRI Yos Sudarso and KRI Teluk Banten intercepted the Portuguese ship Lusitania Expresso in East Timor