Leading naval technology Submarines

Submarines are unique tools for securing national interests. In a world where any movement or asset is exposed, being able to act undetected has never been more crucial. Saab Air-Independent Propulsion (AIP) submarines can remain submerged for longer periods of time, allowing a large range of missions in both peace and wartime. They are the true force multiplier of the 21st century.

To meet diverse, international requirements across an extraordinary spectrum of missions, Saab offers conventional submarines that address three market segments: Pelagic, Oceanic and Oceanic Extended Range (ER).

Each segment represents a technological achievement. By combining a unique range of capabilities, state-of-the-art stealth technology, Air-Independent Propulsion (AIP), high endurance, versatile combat system suite and various weapons, Saab has created a shock-resistant, modular submarine designed for maximum operational flexibility.

Saab submarines are designed for operational interoperability with other organisations and stakeholders, both military and civilian.

Undetectable is undefeatable

Extreme stealth is at the heart of Saab submarines. They are designed to counter all known physical threats, surveillance methods and cyber warfare techniques.

Our new A26 submarines use advanced technology to make them effectively invisible – by balancing the complete range of signatures. This makes them impossible to detect, classify and localise, ensuring you operate undetected by the enemy.

Sweden has a long history of designing silent submarines. The A26 features large, resiliently mounted platforms, using extensive flexible mountings and baffles to minimise structural borne and transient noise, as well as absorb shocks.

To further reduce sound, the space between the frames is filled with acoustic damping materials. This approach is used in unique combination with many other features and methods such as sound-isolated AIP Stirling and diesel engine modules; flexible hoses and compensators; specifying maximum flow speed in air ducts and pipes; minimum bending radius on pipes; and the special design of the hull, fin and casing.

Saab submarines can become virtually invisible

Minimal target echo strength

Minimised infrared signatures

Suppressed magnetic signature

Low radar cross-section

Minimal target echo strength

Unique hull and fin shape
Protected sonar and equipment installation
Acoustic coating
Low hydrodynamic signatures and flow noise both in deep water and during operations at periscope depth

Minimised infrared signatures

Different coatings and smart system solutions
The Stirling AIP engine exhaust gases are cooled and dissolved in water before being released into the sea

Suppressed magnetic signature

Advanced degaussing system controlled by outboard sensors for compensation in all geographical locations and headings
Reduced galvanic signatures (primarily electrical but also secondary magnetic signatures) enabled by a specially designed cathodic protection system
Careful material selection minimises electrical signatures without compromising protection against corrosion

Low radar cross-section

Carefully analysed and selected mast-mounted sensors

Without a trace

The unique, proven Stirling AIP silent propulsion system

The Saab Gotland-class submarine was the first submarine class to have AIP installed during the building process.

In a Stirling engine, the necessary heat is produced in a separate combustion chamber and transferred to the engine's working gas, operating in a completely closed system. The working gas forces the pistons in the engine to move, thus producing mechanical energy.

Since the 1980s, Stirling AIP has been proven to be a mature and robust technology. AIP mode enables the submarine to operate for an extended time, without breaking the surface for snorting and charging the batteries by the diesel engines. The AIP system has been delivered to several export customers and has attained over 30 years of operational service, as well as several tens of thousands of running hours on board submarines. Today, all Swedish submarines are equipped with Stirling AIP.

Compact, modular and manageable, Stirling AIP systems can be dimensioned for fully submerged missions up to 45 days. Thanks to the durability and low cost of operation, the technology is used continuously at patrol speed.

Stirling AIP has an extremely low signature. The diesel engines are only used for long-distance transit at medium speed in either surfaced or snorting condition.

The AIP system burns a mixture of gasified pure industrial liquid oxygen (LOX) and diesel fuel. The same fuel is used for both the diesel and Stirling engines, which enable cost-effective energy production and logistics.

Redefining sea time

Saab submarines, such as the A26, ensure maximum availability and reliability. In order to minimise downtime, any preventive, corrective or mission-critical maintenance can be performed by ordinary crew members using onboard spare parts and test equipment. Where possible, Saab uses Commercial Off-The-Shelf (COTS) equipment to reduce costs and simplify the work.

Submarines

Oceanic

Saab has the world's most modern submarine programme.

Throughout our history we have continuously developed our series of submarines, based on our core Oceanic segment. Its modular design and production method allows the submarine to accommodate a larger and more versatile suite of weapons, various crew sizes, and highly efficient AIP systems.

The Oceanic segment encompasses submarines of similar size and capacity to the A26 submarine, ordered for the Royal Swedish Navy.

Oceanic ER and Pelagic

Our range includes larger and smaller submarines designed for an adapted variety of missions and requirements.

Oceanic ER

Submarines in the Oceanic Extended Range (ER) segment are the largest in the series, designed for much longer missions, greater crew size and increased weapon payload capability. Oceanic ER submarines enable long-distance operations, suitable for any navy using forward deployment of their submarines on extended missions.

Saab has formed a partnership with the famous Dutch shipbuilder Damen in the tender for the replacement of the current Walrus-class submarines. Damen and Saab are confident the ER will be a good solution for international markets with similar requirements.

Pelagic

Saab’s Pelagic segment refers to our smaller submarines, adapted for long-range missions in narrow or littoral environments. Highly manoeuvrable with high speed and a large weapon load, these submarines represent a dangerous threat to any opponent. Pelagic submarines have a lower acquisition price and operating cost and can also be offered with the Stirling AIP technology for superior submerged endurance.

Saab Group

Saab Solutions

Leading naval technology Submarines

Undetectable is undefeatable

Saab submarines can become virtually invisible

Minimal target echo strength

Minimised infrared signatures

Suppressed magnetic signature

Low radar cross-section

Minimal target echo strength

Minimised infrared signatures

Suppressed magnetic signature

Low radar cross-section

Without a trace

The unique, proven Stirling AIP silent propulsion system

Redefining sea time

Submarines

Oceanic

Oceanic ER and Pelagic

Oceanic ER

Pelagic