Continuing Submarine Matters' April 2019 articles on Indonesian submarines Parts 1, 2 and 3:
For more than 37 years (delivered from West Germany in 1981) Indonesia has operated just 2 Cakra class submarines (KRI Cakra 401 and KRI Nanggala 402). As they were often undergoing prolonged upgrades and regular maintenance they were largely a token force. Indonesia may have kept to 2 because the competitor Malaysia had no subs in the 1980s-early 2000s increasing to just 2 Scorpenes in 2007-2008.
The 2 Cakra's are probably inactive most of the time as their hulls (with only a limited number of full immersion cycles) and diesels are wearing out. Perhaps they are now mainly training platforms.
That picture has now changed with the launch of 3 new"Nagapasa class" submarines 2017-2019
- In 2017, DSME delivered KRI Nagapasa 403 to the Indonesian Navy.
- A second Nagapasa KRI Ardadedali was delivered 2018.
- DSME built the modules for the third Nagapasa, KRI Alugoro 405 at Okpo Shipyard, South Korea
and sent them to PT PAL Surabaya for assembly and launch (April 11, 2019).
In November 2018, DSME received the 3 additional Nagapasa orders, announced April 12, 2019 with the subs to be delivered by 2026.
COMBAT SYSTEM (Weapons and Sensors)
A way to estimate what Indonesia's submarines may be used for is to look at the Combat System suite. The Nagapasa class' sensors and weapons are adequate (a match for Malaysia's non-AIP Scorpenes) though perhaps of lower quality and weapons quantity to the Australian neighbours' Collins and Singapore's Invincibles/Type 218s. The strategic threat, China's, latest SSN and SSK submarines, would by superior in quality and quantity to even 6 or 12 Nagapasas. Meanwhile the other neighbour, the Philippines, has no submarines and may only have a couple in the 2030s. The tiny Brunein Navy will probably never have subs.
Weapons
- 8 x 533mm torpedo tubes, with a total of 14 heavyweight shots, including:
= Black Shark torpedoes,
= UGM-84 Harpoon (anti-ship, capable of land attack) missiles.
= maybe 28 torpedo tube launched mines, in a dedicated minelaying mission.
Sensors
The 3 launched Nagapasas aka Improved Chang Bogos have combat systems that include:
- Optronic masts (better than periscopes)
- Atlas Elektronik CSU 90 hull-mounted passive and active search-and-attack sonar and flank sonars - Indra's Pegaso RESM system and Aries low-probability of intercept radar,
- L3's MAPPS integrated platform management systems and
- Safran's Sigma 40XP inertial navigation systems.
MISSIONS
Geography
The Nagapasa class range is 10,300nm (19,000km) combined surface, snorting and fully submerged movement at an average of around 6 knots. This allows them to make a return trip between any two points of Indonesia's very broad 5,120km (from East to West) Archipelago. A mission from the main base at Surabaya, Java to the developing northern forward base at Natuna island, and then patrol, might be common.
Indonesia is a maze of islands and choke points. The Nagapasa's may be able to sit on a chokepoint seafloor for 6 days but not the 2-3 weeks that AIP would permit. No AIP may be due to AIP's high cost and AIP is more suited to Singaporean, Swedish and German style very short missions.
Monitoring non-state actors
Much of mission activity will include monitoring using electronics (ie. signals interception). Such interception "targets" might include the naval and Indonesian coast guard vessels of neighbours (including Australia). China's navy, coastguard and Chinese government backed fishing fleets.
More publically targets of electronic interception might include the shorter range radio signals of difficult to govern non-state actors (see yellow areas of Map A. below) eg. ship/boat hijackers (related to them) pirates, drug smugglers and Islamist separatists/terrorists.
Once a Nagapasa submarine senses a non-state actor target its torpedoes and missiles are too heavy and expensive (more than US$1.5 million per shot) to destroy a small boat. Also you'd blow up people who may only be suspects and blow up all the evidence! So, instead a submarine (using tethered signal buoy beaming to satellite?) may alert an Indonesian Navy patrol boat or Coast Guard patrol boat. That patrol boat may launch a smaller rigid hulled boat armed with machine guns, to deal with the target boat more "gently".
State actors?
More quietly the submarines are capable of monitoring and engaging their neighbours. With only 35 officers-sailors needing accommodation on Nagapasa , on special missions there may be space for:
- around 4 intercept operators/linguists with 4 work stations, or
- around 7 divers-special forces and their equipment for sabotage, intelligence gathering, etc.
Some missions may be to monitor mainly Chinese, US, Australian, Malaysian, Philippine and Singaporean warship and submarine movements. Also monitoring movements of any other navies crossing the Indonesian Archipelago.
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Indonesia has a complex sea and island geography that will prove a challenge for its new Nagapasa submarines.
SOME USEFUL SOURCES
Submarine Matters':
Indonesia's Broad Strategic Picture - Especially Submarines - Part 3, April 17, 2019.
Indonesian Submarine Table Revised: West New Guinea - Part 2, April 16, 2019.
Indonesia's 6 Modern Submarines by 2026, 12? total by 2035 - Part 1, April 15, 2019.
Wikepedia
https://id.wikipedia.org/wiki/Kapal_selam_kelas_Nagapasa (in Indonesian)
Pete
For more than 37 years (delivered from West Germany in 1981) Indonesia has operated just 2 Cakra class submarines (KRI Cakra 401 and KRI Nanggala 402). As they were often undergoing prolonged upgrades and regular maintenance they were largely a token force. Indonesia may have kept to 2 because the competitor Malaysia had no subs in the 1980s-early 2000s increasing to just 2 Scorpenes in 2007-2008.
The 2 Cakra's are probably inactive most of the time as their hulls (with only a limited number of full immersion cycles) and diesels are wearing out. Perhaps they are now mainly training platforms.
That picture has now changed with the launch of 3 new"Nagapasa class" submarines 2017-2019
- In 2017, DSME delivered KRI Nagapasa 403 to the Indonesian Navy.
- A second Nagapasa KRI Ardadedali was delivered 2018.
- DSME built the modules for the third Nagapasa, KRI Alugoro 405 at Okpo Shipyard, South Korea
and sent them to PT PAL Surabaya for assembly and launch (April 11, 2019).
In November 2018, DSME received the 3 additional Nagapasa orders, announced April 12, 2019 with the subs to be delivered by 2026.
COMBAT SYSTEM (Weapons and Sensors)
A way to estimate what Indonesia's submarines may be used for is to look at the Combat System suite. The Nagapasa class' sensors and weapons are adequate (a match for Malaysia's non-AIP Scorpenes) though perhaps of lower quality and weapons quantity to the Australian neighbours' Collins and Singapore's Invincibles/Type 218s. The strategic threat, China's, latest SSN and SSK submarines, would by superior in quality and quantity to even 6 or 12 Nagapasas. Meanwhile the other neighbour, the Philippines, has no submarines and may only have a couple in the 2030s. The tiny Brunein Navy will probably never have subs.
Weapons
- 8 x 533mm torpedo tubes, with a total of 14 heavyweight shots, including:
= Black Shark torpedoes,
= UGM-84 Harpoon (anti-ship, capable of land attack) missiles.
= maybe 28 torpedo tube launched mines, in a dedicated minelaying mission.
Sensors
The 3 launched Nagapasas aka Improved Chang Bogos have combat systems that include:
- Optronic masts (better than periscopes)
- Atlas Elektronik CSU 90 hull-mounted passive and active search-and-attack sonar and flank sonars - Indra's Pegaso RESM system and Aries low-probability of intercept radar,
- L3's MAPPS integrated platform management systems and
- Safran's Sigma 40XP inertial navigation systems.
MISSIONS
Geography
The Nagapasa class range is 10,300nm (19,000km) combined surface, snorting and fully submerged movement at an average of around 6 knots. This allows them to make a return trip between any two points of Indonesia's very broad 5,120km (from East to West) Archipelago. A mission from the main base at Surabaya, Java to the developing northern forward base at Natuna island, and then patrol, might be common.
Indonesia is a maze of islands and choke points. The Nagapasa's may be able to sit on a chokepoint seafloor for 6 days but not the 2-3 weeks that AIP would permit. No AIP may be due to AIP's high cost and AIP is more suited to Singaporean, Swedish and German style very short missions.
Monitoring non-state actors
Much of mission activity will include monitoring using electronics (ie. signals interception). Such interception "targets" might include the naval and Indonesian coast guard vessels of neighbours (including Australia). China's navy, coastguard and Chinese government backed fishing fleets.
More publically targets of electronic interception might include the shorter range radio signals of difficult to govern non-state actors (see yellow areas of Map A. below) eg. ship/boat hijackers (related to them) pirates, drug smugglers and Islamist separatists/terrorists.
Once a Nagapasa submarine senses a non-state actor target its torpedoes and missiles are too heavy and expensive (more than US$1.5 million per shot) to destroy a small boat. Also you'd blow up people who may only be suspects and blow up all the evidence! So, instead a submarine (using tethered signal buoy beaming to satellite?) may alert an Indonesian Navy patrol boat or Coast Guard patrol boat. That patrol boat may launch a smaller rigid hulled boat armed with machine guns, to deal with the target boat more "gently".
State actors?
More quietly the submarines are capable of monitoring and engaging their neighbours. With only 35 officers-sailors needing accommodation on Nagapasa , on special missions there may be space for:
- around 4 intercept operators/linguists with 4 work stations, or
- around 7 divers-special forces and their equipment for sabotage, intelligence gathering, etc.
Some missions may be to monitor mainly Chinese, US, Australian, Malaysian, Philippine and Singaporean warship and submarine movements. Also monitoring movements of any other navies crossing the Indonesian Archipelago.
Map B. Indonesia. See much larger here (courtesy University of Texas). Shows how many islands and chokepoints there are to influence Nagapasa submarine missions. Monitoring non-state actors is likely a big part of the job because illegal non-state actors could politically further fragment Indonesia. Indonesia's more distant islands also share borders (and sometimes interests) with Malaysia's and the Philippines distant islands. All three countries meet in (and patrol) the Tri-Border Area which includes the Celebes and Sulu seas - a place where pirate/hijackers flourish.
Map C. Indonesian seafloor depth map. Showing much of the seafloor between western Indonesia islands is less than 200m deep - making it dangerous for shallow submarine travel in daylight. In such shallow water the magnetic signatures might be more easily detected by aircraft even at night. Meanwhile in eastern Indonesia there are many dangerous to navigate coral reefs (see reddots) between island chokepoints.
Indonesia has a complex sea and island geography that will prove a challenge for its new Nagapasa submarines.
SOME USEFUL SOURCES
Submarine Matters':
Indonesia's Broad Strategic Picture - Especially Submarines - Part 3, April 17, 2019.
Indonesian Submarine Table Revised: West New Guinea - Part 2, April 16, 2019.
Indonesia's 6 Modern Submarines by 2026, 12? total by 2035 - Part 1, April 15, 2019.
Wikepedia
https://id.wikipedia.org/wiki/Kapal_selam_kelas_Nagapasa (in Indonesian)
https://id.wikipedia.org/wiki/KRI_Nagapasa_(403) (in Indonesian)
https://en.wikipedia.org/wiki/Chang_Bogo-class_submarine#Sales
https://en.wikipedia.org/wiki/Chang_Bogo-class_submarine#Sales
Pete