Sachsen-class frigate

Hessen at Kiel Week in 2007

The ships of the Sachsen class are 132.15 meters (433 ft 7 in) long at the waterline and 143 m (469 ft 2 in) long overall. They have a beam of 17.44 m (57 ft 3 in) and a draft of 5 m (16 ft 5 in), though the draft increases to 7 m (23 ft 0 in) at the sonar array in the bulbous bow. They displace 5,690 long tons (5,780 t) at full load. Steering is controlled by a single roll-stabilized rudder; the ships have a turning radius of 570 m (1,870 ft). The frigates have a crew of 38 officers, 64 petty officers, and 140 enlisted sailors. They have accommodations for an additional thirteen officers and sailors as part of a squadron commander's staff, and they have crew provisions for female sailors. The ships can remain at sea for 21 days at a time.[2]

The ships' hulls were designed on the pattern of the previous Brandenburg class to allow for great commonality of parts to reduce maintenance costs; they were built using MEKO modular construction and incorporate seven watertight compartments. The primary improvement over the earlier vessels is the significantly reduced radar signature. The ships were designed with a capacity for an extra 270 long tons (270 t) of weight, to allow for future additions of new weapons and sensors without compromising the ships' efficiency.[2]

The ships of the Sachsen class are equipped with a combined diesel and gas (CODAG) propulsion system. The two operating shafts work independently. The diesel engines are installed in a non-walkable sound-proof capsule. The shafts drive two five-bladed variable-pitch propellers. The General Electric LM2500 PF/MLG gas turbine is rated at 31,500 shaft horsepower (23,500 kW) and the MTU 20V 1163 TB93 diesels provide a combined 20,100 brake horsepower (15,000 kW). The total 51,600 hp (38,500 kW) propulsion system provides a top speed of 29 knots (54 km/h; 33 mph); while operating the diesels only, the ships can cruise for 4,000 nautical miles (7,400 km; 4,600 mi) at a speed of 18 kn (33 km/h; 21 mph). The ships are equipped with four 1,000 kilowatt diesel generators that operate at 400 Volts (V) and 115 V.[2]

Steering is controlled via the Rudder Roll System, which communicates information about the ship's position and rudder dampening signals, allowing the ships to maintain "almost unprecedented stability" in as high as sea state 5.[3]

Sachsen launching an SM-2 missile

These ships were optimized for the anti-air warfare role. The primary anti-air weapons are the 32-cell Mk 41 Mod 10 vertical launching system, equipped with twenty-four SM-2 Block IIIA missiles and thirty-two Evolved Sea Sparrow missiles. Point-defense against cruise missiles is provided by a pair of 21-round Rolling Airframe Missile launchers. The ships are also equipped with two four-cell RGM-84 Harpoon anti-ship missile launchers.[2] In 2013, the German Navy considered modifying the ships' long-range search radar to allow the SM-2 missiles to be used in an anti-ballistic missile capacity.[4]

For defense against submarines, the frigates carry two triple-launchers for the 324 mm (12.8 in) MU90 Impact torpedoes. The ships also carry a variety of guns, including one dual-purpose 62-caliber 76-millimeter (3 in) gun manufactured by OTO Melara. They are also armed with two Rheinmetall 27 mm (1.1 in) MLG 27 remote-controlled autocannons in single mounts.[2]

In January 2003, Hamburg had a modified Panzerhaubitze 2000 turret with a 155 mm (6.1 in) gun fitted experimentally for the Modular Naval Artillery Concept. The experiment was a feasibility study for the projected F125-class frigate. The gun had a range of 40 nmi (74 km; 46 mi) and a rate of fire of 10 rounds per minute.[2]

Sachsen and her sister ships are equipped with a flight deck and hangar that can accommodate two Super Lynx or NH90 helicopters. The flight deck is rated to accommodate a 15-metric-ton (15-long-ton; 17-short-ton) helicopter in conditions up to sea state 6. The helicopter handling system from MBB-Förder und Hebesysteme uses laser guided and computer controlled manipulator arms to secure the helicopter after landing.[2]

The APAR radar

For this role the ships are equipped with an advanced sensor and weapons suite. The primary sensors for this role are the long range surveillance radar SMART-L and the multi-function radar APAR. The SMART-L and APAR sets are highly complementary, in the sense that SMART-L is an L band radar providing very long range surveillance while APAR is an X band radar providing precise target tracking, a highly capable horizon search capability, and missile guidance using the Interrupted Continuous Wave Illumination (ICWI) technique, thus allowing guidance of 32 semi-active radar homing missiles in flight simultaneously, including 16 in the terminal guidance phase.[5][6] The ships are also equipped with two STN Atlas 9600-M ARPA navigation radars.[7]

In 2013, Atlas Elektronik and Thales Deutschland were awarded a contract to modernize the frigates command system, with the project to be completed by 2017.[8]

In August 2021, the German armed forces' procurement agency (BAAINBw) awarded a contract to German and Israeli companies Hensoldt and IAI, under which the Sachsen-class frigates will have their obsolete SMART-L long-range radar replaced by a new AESA radar system designated as TRS-4D/LR ROT.[9] It will be capable of tracking "very small and maneuverable" targets at distances of more than 400 km for air targets and up to 2,000 km for targets in earth orbit. This includes long-range ballistic missiles, allowing Germany to participate in NATOs BMD (ballistic missile defence) efforts. It is not planned to fit an anti-ballistic missile such as the SM-3 to the ships. The ships IFF systems will also be modernised.

Before installation of the three shipborne radars commences, an additional first unit will in 2023 be installed at a coastal facility near the Naval School of Technology at Parow in the state of Mecklenburg-Western Pomerania for purposes of training and evaluation. The first ship is planned to have its radar installed in 2024 and all three ships are to have been fitted with the new system by 2028.

The same Hensoldt/IAI system has also been selected by the German Air Force in order to replace its stationary HR-3000 - or HADR (Hughes Air Defense Radar) - early warning radars.

Rumors emerged in July 2013 that the Israeli Navy had agreed to procure two destroyers from Germany for €1 billion. These had been rumored to be Sachsen-class vessels.[14][15] Eventually, Israel purchased four Sa'ar 6-class corvettes—significantly smaller vessels—from German shipyards in 2015.[16]