U.S. Navy Buys 4 Saab MK66 Undersea Targets to Boost Anti-Submarine Warfare Training.

The U.S. Navy is adding four Saab MK66 Heavyweight Undersea Training Targets, according to a June 29, 2026, contract award, giving its anti-submarine warfare forces more realistic submarine-like contacts to detect, track, classify, and engage during training.

The recoverable 21-inch autonomous targets can imitate submarine acoustic behavior and support exercise torpedo engagements without using live submarines. This strengthens undersea warfare readiness as Western navies place renewed emphasis on ASW training, acoustic deception, and credible deterrence in contested maritime environments.

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Saab will deliver four MK66 Heavyweight Undersea Training Targets to the U.S. Navy under a $23,19 million contract, providing recoverable autonomous acoustic targets that replicate submarine signatures for more realistic anti-submarine warfare training (Picture source: Saab).

The MK66 is not an armed undersea weapon in the conventional sense. It carries no explosive warhead and is not intended to attack a submarine or surface ship. Its combat-relevant payload is its acoustic generation suite: a programmable target system that can present active and passive submarine-like signatures to sonars, combat systems and torpedo fire-control teams. Saab’s published data gives the AUV62-AT a 21-inch diameter, roughly matching the diameter class of heavyweight torpedoes, an approximate weight of 800 kg, submerged speed from 3 to 12 knots, surface speed from 0 to 3 knots, and an operating depth from the surface to 300 meters. Endurance is listed at more than three hours at 10 knots, more than nine hours at 6 knots, and more than 18 hours at 3 knots, which allows instructors to trade speed, geometry, and training duration depending on the exercise profile.

The target’s “armament” is therefore acoustic rather than kinetic. In active mode, the AUV62-AT uses a programmable echo repeater with a frequency response from 1 kHz to 100 kHz, target strength adjustable from -20 dB to +20 dB, and output listed at 175 dB referenced to 1 µPa at 1 meter. In passive mode, it can generate noise, tonals, modulations, speed-dependent signatures, and pre-recorded acoustic profiles across 25 Hz to 100 kHz. The vehicle uses low-, medium-, and high-frequency transducers, hydrophones in the hull and towed tail, and a target elongation function that allows the acoustic presentation to be adjusted to represent different submarine sizes and strengths. This matters because anti-submarine warfare training is not just about finding a sound source; crews must evaluate bearing rate, aspect, Doppler behavior, false contacts, environmental clutter, and whether a contact is sufficiently classified to justify an engagement.

The development path explains the Navy’s current procurement logic. Saab states that AUV62-AT is a development of its Type 62 torpedo, giving the target a torpedo-derived underwater vehicle architecture rather than a disposable acoustic buoy design. In January 2018, Saab announced that the U.S. Navy would evaluate the AUV62-AT through the Foreign Comparative Testing program, with a summer 2018 demonstration and an option to continue testing into 2019. That evaluation was tied to the Navy’s search for a replacement anti-submarine warfare training system for the Undersea Warfare Training Range. A later federal contracting notice described the MK66 Mod 0 Heavyweight Undersea Training Target as a modular, scalable and configurable autonomous underwater vehicle system used as an artificial acoustic target on instrumented ranges and in open-ocean environments.

For the U.S. Navy, the need is practical rather than theoretical. Nuclear attack submarines, allied diesel-electric submarines, P-8A Poseidon aircraft, MH-60R Seahawk helicopters and surface combatants are all high-demand assets, and using a manned submarine as a routine target consumes crew time, maintenance margin and operating days that could otherwise support deployments, certification events or fleet experimentation. NAVAIR has described the Undersea Warfare Training Ranges as instrumented environments that allow ships, submarines and aircraft to track surface and subsurface targets for anti-submarine warfare training, with undersea cables, acoustic sensors, shore-based control, display and processing systems. In 2022, the Navy said the Increment I range off Florida added 500 nautical miles of instrumented littoral training area and supports realistic training and tactical development for submarine, surface ship and aircraft undersea warfare forces.

The MK66 gives those ranges and open-ocean events a repeatable target that can be reprogrammed, recovered, debriefed and used again. Saab’s documentation states that mission planning, control and evaluation are conducted through a PC-based operator console, with missions loaded before the exercise and noise settings tailored to the training objective. A 2019 AUV62 technical presentation identified key functions including simultaneous handling of multiple vehicles, training of the full locate-track-attack sequence, ship-to-ship and ship-to-helicopter cooperation, and use of the AUV62-AT as a torpedo target during exercises. The important point is that the target supports the whole kill chain, not only sonar operator familiarization.

At tactical level, this type of target can expose weaknesses that classroom simulators often miss: poor contact handover between a destroyer and helicopter, late classification by a maritime patrol aircraft crew, unstable track quality before a torpedo exercise shot, or confusion between biologics, merchant traffic and submarine-like signatures in shallow water. At acquisition level, four vehicles for $23.19 million is a small buy compared with combat ships, aircraft or torpedoes, but the contract supports a larger readiness requirement: generating more at-sea repetitions against a controllable underwater contact without assigning a live submarine to every event. The Navy’s decision to buy MK66 targets therefore reflects a measurable training problem: the fleet needs more realistic submarine signatures, more instrumented debrief data, and more opportunities to rehearse coordinated anti-submarine warfare before crews face real undersea contacts in contested waters.

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Written by Evan Lerouvillois, Defense Analyst.

Evan studied International Relations, and quickly specialized in defense and security. He is particularly interested in the influence of the defense sector on global geopolitics, and analyzes how technological innovations in defense, arms export contracts, and military strategies influence the international geopolitical scene.