Indonesia Validates KSOT Submarine’s Torpedo Launch to Watch Its Archipelago Waters.

Indonesia’s state shipbuilder PT PAL and the Indonesian Navy conducted the first torpedo firing from the KSOT autonomous submarine prototype on October 30, validating an externally launched 324 mm Piranha lightweight round.

On October 30, 2025, Indonesia confirmed the first torpedo firing from its KSOT autonomous submarine off Surabaya, releasing a 324 mm Piranha lightweight round from an externally mounted starboard launch tube after pier-side loading by crane. Imagery and statements indicate the vehicle remained partially submerged for much of the event, which served to validate safe separation and command sequencing from an unmanned host.
Follow Army Recognition on Google News at this link

The 324 mm Piranha lightweight torpedo launched from KSOT provides a compact ASW weapon for prosecuting submarines and small surface threats in confined waters (Picture source: Indonesia MoD/ PT PAL).

The shot matters because it proves a complete lightweight-torpedo kill chain on an extra-large UUV. The KSOT prototype is listed at 15 meters long, 2.2 meters in beam, and 1.85 meters draught, with PT PAL claiming growth performance up to 20 knots and operating depths to 350 meters. Earlier engineering briefs described a 37.3-ton displacement, cruising at 5 knots with a maximum of 8 knots, roughly 90 nautical miles over 18 hours, and an initial diving depth near 50 meters, figures consistent with early test articles that will scale as the power and autonomy stacks mature.

The armament showcased was a 324 mm training configuration of the Piranha, a domestic lightweight torpedo class suited to anti-submarine warfare in confined waters. While propulsion and seeker details remain undisclosed, the dry launch from an external tube is a pragmatic choice for a compact hull because it preserves internal volume and simplifies maintenance. PT PAL also unveiled a truck-based Autonomous Submarine Command Centre to control KSOT over line-of-sight and satellite links, laying the groundwork for manned–unmanned teaming with surface combatants and patrol aircraft.

Indonesia’s defense minister said the ministry will procure 30 KSOTs to seed chokepoints, notably the Sunda and Lombok Straits, under the Navy’s Submarine Operations Command. Lightweight torpedoes give the fleet a scalable response against intruding submarines and small combatants, while the attritable unmanned platform absorbs risk that would otherwise fall on crews. The concept fits the archipelagic geography, where quiet persistence and local magazine depth can outweigh blue-water endurance.

The development arc has been unusually fast: KSOT appeared publicly during the Indonesian Armed Forces’ 80th anniversary parade on October 5, PT PAL detailed configurations on October 8, and then the first torpedo launch followed on October 30 in Surabaya in the presence of senior defense leaders. The program has always been framed in three variants: surveillance, one-way attack, and the torpedo-armed vehicle demonstrated this month, signaling a modular approach to payloads as the architecture stabilizes.

Compared with global peers, Indonesia is prioritizing near-term lethality close to home. The United States is fielding the much larger Orca class and Australia is scaling Ghost Shark, but Jakarta’s 15-meter vehicle with lightweight weapons may deliver earlier operational payoff inside Indonesia’s sea lanes. Performance claims have varied across briefings, which is normal for a prototype moving toward a fleet standard, yet the public firing shows software, power, launcher geometry, and C2 are already integrated at sea.

Regional outlets and analysts are watching, but Indonesia has not announced foreign customers for KSOT or Piranha. For now, the program is a sovereign capability play that also raises PT PAL’s profile as a systems integrator in unmanned undersea warfare. If the first production tranche delivers even a dozen torpedo-capable vehicles quickly, Indonesia will gain a persistent screen that cues manned ships and submarines, complicates adversary planning in straits, and strengthens deterrence without expanding the manned submarine force.