At next week’s Euronaval exhibition in Paris, Saab will be unveiling the latest version of its Lightweight Torpedo (SLWT). Already ordered by Sweden and Finland, the compact submarine hunter/killer weapon is designed to be launched from a variety of sea and air platforms and is tailored to both blue water conditions and the complex environment of the shallow Baltic Sea.
With increased tensions between Russia and NATO, as well as China’s growing regional and global ambitions, anti-submarine systems are gathering interest at a level not seen since the Cold War. This is especially true in dealing with possible Russian incursions in the Baltic, which is notorious for its shallow water, variable salinity, temperature layers, complex seabed topography and the bewildering noise levels caused by heavy sea traffic.
To deal with this ideal submarine hidey hole, Saab has been developing its SLWT system aimed at both the Swedish Royal Navy and global export markets. Though it can operate in the open sea, Saab says the new torpedo works best in dealing with littoral anti-submarine warfare.
At first glance, the SLWT doesn’t seem like much when compared with the huge torpedoes like the US Mark 48 and British Spearfish. It’s only 2.85 m (9.35 ft) long, 40 cm (15.75 in) wide and weighs in at 340 kg (750 lb) soaking wet, but inside, it has a state-of-the-art, fully digital homing system that gives it a fire-and-forget and wire-guided capability.
Small enough to be launched by submarines, surface ships, helicopters, airplanes, or from improvised launchers, the SLWT’s electric pump jet powered by a lithium-based rechargeable battery can propel it at over 40 knots (46 mph, 74 km/h) and at depths of over 300 m (1,000 ft) for more than an hour.
Additionally, the SLWT is an intelligent weapon. Operated either autonomously or by wire using a two-way data connection, the torpedo can pilot a preset search pattern or series of waypoints while scanning with its multi-beam active/passive sonar system. As it does so, it can adapt to changes in temperature and salinity, while its onboard computer can distinguish between rock outcroppings, wrecks, and active submarines as well as navigate around obstacles.
Saab says that once engaged with a hostile craft, the SLWT can pursue, attack, and even break off and re-engage multiple times. It can even distinguish between submarines and active decoys and can work with other torpedoes to pen in a target. After pressing in its attack, the torpedo’s PBX omnidirectional explosive warhead can deliver the fatal killshot.
Another feature of the SLWT is that it can be ordered to abort an attack at any time or go into training mode. If it does so, the torpedo will not strike the target, but will veer off and activate a flotation mechanism, so it can be recovered and its onboard data studied for mission evaluation.
“The SLWT project is going very well,” says Stefan Sjögren, Programme Director, Lightweight Torpedoes at Saab. “We are in the process of finalizing the second demonstration torpedo with all the features as in the final product. We are bringing key advances in torpedo technology to SLWT, which translates into endurance, accuracy, and complete control.”
The Euronaval exhibition runs from October 23 to 26.