Swedish Navy’s anti-submarine warfare in the Baltic Sea

To battle submarines in the Baltic Sea, you need to have a torpedo developed specifically for the Baltic Sea, Swedish torpedo developers have said.

In a recent article posted on the Defence Materiel Administration website, Sweden’s torpedo developers explain what a process to develop and produce a new light weight torpedo system for the Swedish Navy entails.

The development is conducted by defence contractor SAAB Dynamics and by 2022 the torpedo system is supposed to be ready to fire from surface vessels and submarines.

The Baltic Sea offers a wide array of challenges regarding finding intruding submarines. The torpedo system that the Swedish Armed Forces (SwAF) use to neutralize a submarine faces the same challenges.

Factors contributing to these challenges are the shallow waters of the Baltic Sea, the sea floor topography and the sea floor material. These factors complicate target detectability for the sonar systems. The brackish water, the complexity of the archipelago and the intense marine traffic are also complicating factors.

“These factors result in tough requirements on the torpedo sensor systems, which must be tailored specifically for the environment in the Baltic Sea. The torpedo must also be able to operate in different speeds, depending on the environment, and be able to navigate and communicate efficiently with the launching platform.”

This is told by Magnus Lind, the program manager for the new torpedo system which is primarily dedicated to the Swedish submarines and the Visby class corvettes, but also prepared for integration on ASW helicopters. He doesn’t hide the fact that there are quite a few challenges for the FMV project he is managing.

“The prerequisites in the Baltic Sea can´t be altered, but I rest assured that we have the competence and experience to overcome the difficulties.”

In order to handle the challenges, the FMV project has a close collaboration with the industry and support from FOI, the Swedish Defence Research Agency, as well as from the SwAF. In six years the torpedo system shall be fully integrated and operational on the corvettes and submarines.

“Is it necessary to spend all this time to develop and manufacture a new torpedo system? The short answer is yes. We are facing the development of the next generation light weight torpedo. We have very special conditions in the Baltic Sea and we have the tough requirements on the system itself, all leading us up to a very advanced level of technology. The system safety and system capability requirements for these types of systems are of course very tough as well.”

Since the early sixties, four light weight and two heavy weight torpedo systems have been developed in Sweden. Magnus Lind points out that this has provided a solid knowledge base to build upon.

“We do not start from scratch, on the opposite we take advantage of not only knowledge and experience from previous efforts but also existing solutions regarding launch control systems on surface vessels and submarines. This results in a cost efficient torpedo systems and a seamless transition the system in use today.”

In order to reduce the technical risks and stay within budget in the development phase for the new torpedo, FMV has used a model where the design has been adapted to available financial resources and time, but with the capability to further update and improve the torpedo making evolutionary development of the torpedo system possible.

An important piece of the puzzle is the modular design of the torpedo, where some components already available on the market are used, thus making it possible to share technology and solutions with other torpedo systems used by the SwAF.

The modular concept also simplifies maintenance and makes it easier to implement new technology and add new functions. The warhead in the torpedo is also exchangeable to a training module so that education and training is performed using the same vehicle, thus eliminating the need for special training torpedoes.

“The concept with a modular design is inherited from earlier development programs and we have successfully used it on other underwater vehicles such as the AUV62-AT (autonomous training target for ASW).”

The development process is in the hands of the contractor, Saab, where the verification of the individual modules also is performed. At this time the work is focused on the battery module and the electrical motor. Recently Saab performed a bench test of the motor and battery regarding velocity and endurance.

“I am very pleased to see that the work done by Saab now has full speed ahead on the different subsystems and is on schedule. We have a close collaboration with Saab, providing full insight in the development of this advanced torpedo that will give Sweden an improved defence capacity,” says Magnus Lind.