Kockums A26 Submarine, Sweden
Type A26 submarines being built by Saab will serve Swedish Defence as successors to Gotland-class submarines. Type A26’s mission capabilities include maritime security, covert mine countermeasure, intelligence gathering, surveillance, reconnaissance, covert in hostile areas, anti-submarine warfare, anti-surface warfare, mine-laying, underwater work, and other special operations.
Saab has been contracted by the Swedish Defence Material Administration (FMV) to construct, verify and deliver two Type A26 next-generation submarines for the Swedish Navy. It received an order from the FMV to procure sensor systems for the Type A26 in December 2014.
The FMV further awarded a contract worth Skr7.6bn ($925m) to Saab for the construction, verification and delivery of two A26 submarines in June 2015.
The first submarine’s first steel was cut at Saab’s Kockums shipyard in September 2015. Deliveries will begin in 2022 and continue through to 2024.
A26 submarine design and features
The Kockums A26 submarine’s modular hull structure, made from special steels, offers high-seakeeping performance and operational effectiveness. The X-rudder configuration with four independently controlled control surfaces provides high-manoeuvrability. The submarine requires low operating and maintenance costs.The submarine is 62m-long and has a draught of 6m and a displacement of approximately 1,800t when surfaced. The Scandinavian design offers spacious and comfortable seating for up to 26 personnel. Two crew members are assigned to the same bunk in rotation based on the hot bunk principle.The submarine has two pressure-tight compartments and a pressure-tight, mid-tank section. An escape tower on top of the mid-tank section facilitates emergency escape for crewmen.All applicable management and control systems of the submarine are interconnected through the vessel’s general management services system (GMSS). All subsystems are operated from common multifunctional consoles (MFCs), whereas all major ship systems are controlled through the ship control and monitoring system (SCMS).
The submarine can be upgraded with the installation of a hull section in the forward or aft compartment. The forward section can be equipped with additional space for workstations, accommodation and other equipment. An additional diesel and/or Stirling AIP engine can be placed in the aft section.
Equipment carried on A26 submarine
A large, flexible payload stowage compartment allows carriage of a variety of mission payloads to deliver a high degree of operational flexibility. The pressure-tight containers, unmanned underwater vehicles (UUVs), remotely operated vehicles (ROVs), and reconnaissance and rescue systems can be carried externally.
Move cursor over picture to see detailsThe submarine employs a 6m-long Multimission Portal™ for the launch and recovery of up to eight divers along with their mission payloads. The UUVs can be deployed in mine searching and clearance operations, and the unmanned maritime vehicles are used to gather acoustic, visual, electronic and communication intelligence data.
In order to facilitate secure system integration, future upgrading and expansion, as well as reduce costs, all parts of the Combat System are interconnected through the combat system infrastructure (CSIS).
This is the backbone of all information systems in the combat system and comprises an open architecture distributed system that integrates combat subsystems in a secure way according to Saab’s IT security architecture. To cut lead times and costs, the CSIS is mainly based on easily obtainable commercial off-the-shelf (COTS) products, technologies and standards, adapted and/or applied to naval military applications.All applicable subsystems are interconnected through the CSIS and operated from common multifunctional consoles (MFCs). CSIS access points throughout the submarine enable easy connection for a large number of additional subsystems, MFCs, workstations and laptops.
Decentralized Combat Management
The combat system of the Kockums A26 submarine is managed from a Saab combat management system (CMS) specially developed for this submarine. Notably, instead of being a central system to which all other systems are integrated, the CMS is a subsystem linked to the CSIS which communicates using open standards. This allows integrated systems, including the CMS, to be individually upgraded or exchanged, thereby greatly reducing project risks typically found with large, complex and highly integrated systems.The CMS allows high-performance data exchange via the CSIS with other systems like sonar, Electronic Support Measures (ESM), weapon interface systems and the vessel control system. Like most other subsystems connected to the CSIS, the CMS can be operated from any MFC in the submarine.
Navigation and communications
The Type A26 submarine is equipped with mast-mounted optronic sensor systems, as well as active and passive sonar systems for the identification and detection of threats.Advanced network-centric communication capabilities enable the submarine to integrate them with other forces on the land, sea and in the air. External communication is provided though radio, hydroacoustic and shore-connected methods.
The weapon system is managed from a Saab combat management system (CMS) that is connected with the GMSS.
Countermeasures and safety features
The GHOST® Genuine Holistic Stealth technology makes the Type A26 invisible and quiet. The submarine has low hydrodynamic and infrared signatures, and low radar cross-section.The submarine is resistant to significant shock loads from underwater explosions. It is fitted with mine countermeasures to detect, identify and destruct mines. An emergency, high-pressure, air-blowing system is fitted to help bring the submarine to surface in the event of flooding. The submarine is also equipped with a fire-protection system designed as according to SOLAS requirements.
Propulsion and performance of A26 submarines
The main propulsion system of the Type A26 submarine is fully-integrated Kockums Stirling air-independent propulsion (AIP) system, which burns gasified pure industrial liquid oxygen (LOX) and diesel fuel. The submarine is also equipped with a conventional diesel-electric propulsion system.The maximum submerged AIP speed of the submarine is more than 6k, maximum continuous snorting speed is 12k, diving depth is more than 200m, mission endurance is 45 days, and operating sea water density is between 1,003kg/m³ and 1,032kg/m³. The submarine can withstand temperatures ranging from -2°C to 32°C.
Securing Total Control
Submarine operations in the extreme littorals are also facilitated by the difficulty of carrying out anti-submarine warfare (ASW) in shallow water. A confusing combination of big thermal variations in water layers, unpredictable tides and currents, high reverberation and highly directional ambient noise defeats ASW measures.
This is why the next-generation Kockums A26 submarine, with superior GHOST® (Genuine HOlistic STealth) properties and AIP, is a valuable asset in securing total control in the extreme littoral zones, or as we call it, Littoral Supremacy