South Africa's SAS Manthatisi submarine returns to active service after fatal 2023 incident.

On September 1, 2026, the South African Navy confirmed that the Heroine-class submarine SAS Manthatisi (S101) officially returned to deployable status following certification trials off Naval Base Simon's Town. This milestone restores operational seagoing submarine capability to the fleet 35 months after a September 2023 training accident off Kommetjie resulted in three fatalities. The vessel achieved full recertification after extensive sea trials and participation in Exercise Red Lion 2026, validating safety procedure overhauls and equipment upgrades.

The SAS Manthatisi (S101) completed Operational Sea Training certification and Exercise Red Lion 2026 following rigorous safety overhauls, returning as South Africa's sole active Type 209/1400MOD submarine. Sister vessels SAS Charlotte Maxeke (S102) and SAS Queen Modjadji I (S103) remain in a R136 million Phase One refit pipeline, leaving fleet availability dependent on a single hull while long-term mid-life modernization requirements remain outstanding.

Related topic: Indian Navy and South African Navy sign agreement to enhance submarine rescue cooperation

The South African Navy submarine SAS Manthatisi (S101) was seen on July 30, 2026, departing Naval Base Simon's Town for the first time since 2023 following maintenance work. (Picture source: X/Dean Wingrin)

On September 1, 2026, the South African Navy confirmed to Cape Argus that the Heroine-class submarine SAS Manthatisi (S101) had returned to deployable status, 35 months after the September 20, 2023, Kommetjie accident that claimed three lives. This status follows engineering checks, equipment inspections, safety verification, damage control drills, emergency response testing, casualty procedures, seamanship assessment, and separate Operational Sea Training certification of the boat and crew. The SAS Manthatisi had already been observed operating from Naval Base Simon's Town and in False Bay in late July and early August before joining Exercise Red Lion 2026, whose sea phase ran from July 27 to August 28.

The return nonetheless restores only one of South Africa's three submarines to confirmed seagoing activity, as both SAS Charlotte Maxeke (S102) and SAS Queen Modjadji I (S103) remain in an R136 million refit effort, while the SAS Manthatisi's own mid-life update, scheduled for 2022, remains outstanding. The September 20, 2023, accident occurred off Kommetjie near Slangkop Lighthouse while the surfaced SAS Manthatisi was conducting a vertical replenishment with a Super Lynx helicopter during transit from Simon's Town toward Cape Town. Seven members of the casing party were swept overboard in high seas, triggering a recovery operation by the helicopter crew and NSRI Kommetjie. Lieutenant Commander Gillian Elizabeth Hector, Master Warrant Officer William Masela Mathipa and Warrant Officer Class One Mmokwapa Lucas Mojela died, while the four remaining personnel survived.

The subsequent safety changes were substantial: casing safety lines were modified, harness lines shortened, IMO-compliant life jackets introduced, and hard hats made mandatory for relevant casing operations. Procedures were also rewritten because the submarine doctrine in force did not contain a contingency for the entire deck party becoming man-overboard casualties at the same time. The Board of Inquiry was completed on October 25, 2024, and the Hawks requested assistance on June 5, 2025, later receiving inquiry material and access to the submarine for a homicide investigation. The SAS Manthatisi's return, however, should be separated from its unresolved life-extension requirement, as South Africa contracted for these three Type 209/1400MOD submarines in July 2000 under Project Wills.

The SAS Manthatisi itself was built by HDW in Kiel, launched on June 15, 2004, commissioned on November 3, 2005, and arrived at Simon's Town on April 8, 2006. It was placed in reserve in 2007 under a force-generation model intended to rotate the three Heroine-class submarines through operational service, training, and maintenance. A major overhaul began in 2010 and ended with its return in October 2014. That work included the replacement of all 480 battery cells, weighing about 250 tonnes in total, at a reported cost of R35 million. By April 2023, the SAS Manthatisi had completed Docking and Essential Defect work and entered post-maintenance trials, but its separate mid-life update scheduled for 2022 had not begun.

Consequently, by September 2026, it had been commissioned for 20 years and 10 months and had gone 11 years and 11 months since its October 2014 return from the previous major overhaul. Current certification therefore confirms short-term operational availability, not the completion of the modernization needed to sustain the submarine deeper into its third decade. The base of the Heroine-class, the German Type 209/1400MOD, is 62 m long, 7.6 m in beam and displaces about 1,450 tonnes surfaced and 1,600 tonnes submerged, with a normal crew of 30. Four MTU 12V 396 diesel engines produce a combined 2.8 MW through four alternators, feeding a Siemens electric propulsion motor rated at 3.7 MW and driving a single shaft; another class figure places propulsion output at 6,100 shp, equivalent to 4.5 MW.

Maximum speed is 10 kt surfaced and 21.5-22 kt submerged, resulting in an 11,000 nmi surfaced range at 10 kt, and an 8,000 nmi snorkeling range at 10 kt. Battery-only range is 400 nmi at 4 kt, before deductions for maneuvering, hotel load, and reserve. The SAS Manthatisi's combat system, for its part, is built around passive detection first, with active sensors available when required. Atlas Elektronik's ISUS 90-45 integrates navigation, tactical management, sensor processing and torpedo fire control. Its CSU 90 sonar suite combines hull-mounted active/passive search-and-attack sonar, flank arrays, active-intercept capability and own-noise monitoring.

On September 20, 2023, high seas swept seven of the SAS Manthatisi's crew members overboard during a vertical replenishment exercise off Kommetjie, ultimately resulting in the deaths of three South African Navy sailors. (Picture source: Wikimedia/PLJphotoMan)

For visual and electromagnetic surveillance, the submarine uses an I-band surface-search radar, a hull-penetrating SERO 400 attack periscope and an OMS 100 optronic mast carrying stabilized high-definition television and third-generation thermal imaging. Saab's S/UME-100 ESM/ELINT suite includes radar warning, emitter interception, electronic-intelligence analysis, and amplitude direction finding through antennas incorporated into the mastheads. In operational terms, the submarine can build contact information through three separate passive channels before transmitting: acoustic detection through sonar, interception of radar emissions through ESM, and short optical or infrared mast exposures. That permits active sonar and surface-search radar to remain off when the tactical cost of revealing the submarine's position exceeds the information benefit.

The SAS Manthatisi has eight 533 mm bow tubes and can embark up to 14 AEG SUT 264 torpedoes, allowing eight weapons to be loaded in the tubes and six retained as reloads when carrying the maximum inventory. The SUT 264 provides both anti-surface and anti-submarine engagement capability through the ISUS 90 fire control system. Provision existed for UGM-84 Sub-Harpoon integration, but South Africa did not procure or integrate the missile, so the submarine does not possess a confirmed stand-off submarine-launched anti-ship missile capability. Its offensive reach therefore depends on remaining undetected long enough to close to torpedo-engagement distance. The same low-signature characteristics support intelligence collection, maritime reconnaissance and special forces insertion.

During Exercise Amazolo in September 2007, the SAS Manthatisi managed to penetrate a seven-ship anti-submarine screen that included SAS Amatola, SAS Isandlwana and the U.S. Navy cruiser USS Normandy before conducting simulated attacks against the protected target and surface combatants. Fleet availability remains the more consequential problem. The Heroine-class consists only of three submarines, all commissioned between 2005 and 2008 and based at Simon's Town. By 2019, two submarines already required "urgent and complete" refits, and Armscor warned that the submarine capability could become unavailable after FY2022/23 if the work was not undertaken. The Phase One contract for S102 and S103 was only awarded in October 2025, about six years after that warning and five years after the recommended 2020 contracting point.

Its value is R136 million for both hulls, mathematically equivalent to R68 million per submarine if divided evenly, and completion is scheduled for November 2026. Phase One covers surveys, configuration reviews, inspections, and preservation rather than completion of the full refits. This means two of the fleet's three hulls are still inside the sustainment pipeline, while the only boat back at sea, S101, has an incomplete mid-life update dating from 2022. South Africa therefore has three submarines in inventory but only one currently confirmed as fleet-active. If the SAS Manthatisi enters docking, suffers a major machinery defect, requires another large battery intervention, or begins its deferred mid-life update before one of the other submarines returns, confirmed operational availability could fall again from one submarine to zero.

The problem is reinforced by age concentration: the three hulls entered service in 2005, 2007 and 2008, so by 2026 the entire class is between 18 and 21 years old and approaching major maintenance thresholds within the same period rather than in staggered generations. Rescue capacity also depends on an external partner. The South African Navy does not operate an indigenous Deep Submergence Rescue Vessel (DSRV), so Vice Admiral Monde Lobese and Indian Navy Chief Admiral Dinesh K. Tripathi signed an implementing agreement on September 3, 2024, under which India can deploy a DSRV for a South African submarine emergency. India then carried out Rescue Seat Certification on S101 at Simon's Town in August 2025, verifying the physical interface required for the rescue vehicle to mate with the submarine and transfer personnel.

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Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, South Korea, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.