Naval Weapons

40 Mk 4 gun selected for Finland’s Hamina MLU

01 February 2018
The Finnish Navy’s Hamina-class FAC will be equipped with Bofors 40 Mk 4 40 mm naval guns. Source: BAE Systems

BAE Systems Weapon Systems – Sweden is to supply Bofors 40 Mk 4 naval guns to equip the Finnish Navy’s Hamina-class fast attack craft (FAC) as part of the Squadron 2000 mid-life upgrade (MLU) programme.

The company revealed on 30 January that it had been contracted by Squadron 2000 MLU prime contractor Patria for an undisclosed number of 40 Mk 4 systems. The new 40 mm mounting will replace the existing 57 Mk 3 57 mm gun on board the four Hamina-class vessels.

Development of the Bofors 40 Mk 4 mounting began in 2009 with the aim of providing small inshore patrol craft and offshore patrol vessels with a compact, lightweight, and affordable multirole weapon system. While tracing its origins back to the Mk 3, the successor Mk 4 mounting has been substantially re-engineered to bring weight down to less than 2,500 kg without ammunition. To achieve this reduction, a new elevating mass (brought across from the Swedish Army’s CV 90 armoured vehicle family) has been introduced, electric drives have supplanted hybrid electro-hydraulics, and a fully digitised modular system architecture is adopted.

The 40 Mk 4 has a cyclic rate of fire of up to 300 rds/min, and is fully compatible with BAE Systems’ programmable 3P (prefragmented, programmable, proximity-fused) ammunition. Programmed at the point of firing according to the threat type and engagement scenario, 3P ammunition can be programmed in any one of six different modes to optimise effect according to different threat types: gated proximity for air defence; gated proximity mode with impact priority (air defence large targets); time mode (against small, fast, and manoeuvring surface targets and concealed onshore targets); impact mode for engaging surface targets; armour-piercing mode against armoured surface targets; and proximity in the default mode.

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