Babcock’s signing of a Memorandum of Understanding (MoU) with BAE Systems Bofors on a naval gun support package for the Royal Navy’s future Type 31 frigates has shone the spotlight onto the unique 57mm and 40mm naval gun configuration the class will feature.
Detailed in an 18 September release, Babcock said the MoU was signed in anticipation of an in-service support opportunity for the Bofors 57mm Mk3 systems and 40mm Mk4 systems fitted across the Type 31 frigate class.
Each Type 31 frigate will be equipped with a single 57mm main gun and two 40mm secondary weapons systems, offering considerable short-range conventional deterrence against small vessels, drones, anti-ship missiles, and fast attack craft.
Babcock, which is manufacturing the Type 31 frigates at its Rosyth shipyard, is already working with BAE Systems integrating the Bofors weapons systems onto the lead ship in class, HMS Venturer.
Both the 57mm and 40mm naval guns will be newcomers to the Royal Navy, which is undergoing an extensive warships replacement programme in a bid to solve critically low hull numbers and diminished capability.
Babcock currently provides in-service support to Royal Navy naval gun systems including the 4.5” Mk8 gun used across the old Type 23 frigates and Type 45 destroyers, the widely used Phalanx CIWS, and the GSA9 gunfire control system fitted to the Type 45 destroyers.
Type 31 main gun: Bofors 57mm
Also known as the BAE Systems 57mm Mk110, the Bofors 57 Mk3 is typically used for operations in the littoral zone, where warships operate closer to shore and thus potentially vulnerable to onshore threats, as well as combating fast attack craft and patrol boats.
Standard specifications
| Elevation | -10° to +77° |
| Total weight of gun excl. ammunition | 7,000kg |
| Maximum range | 17,000m |
| Rate of fire | four rounds per second |
| Muzzle velocity | 1,035m/s |
| Number of rounds available in gun | 120 |
The system is the deck gun of choice for the US Navy’s Littoral Combat Ships and the US Coast Guard’s large National Security Cutters, the latter of which are a similar size and weight compared to the UK’s incoming Type 31 frigates.
Secondary guns: Bofors 40mm
Intended to complement the single 57mm Mk3/Mk110 on the Type 31 frigates will be two 40mm secondary weapon systems, one mounted in an elevated position just behind the main gun with the second installed aft on top of the helicopter hangar.
In this configuration, the two Bofors 40mm guns will offer a wide arc of secondary defence to complement the 57mm Mk3/Mk110.
Standard specifications
| Elevation | -20° to +80° |
| Total weight of gun excl. ammunition | 2,300kg |
| Maximum range | 12,500m |
| Rate of fire | 300 rounds/min |
| Muzzle velocity | 1012 m/s (3P ammunition) |
| Number of rounds available in gun | 100 |
With the Type 31 expected to be relatively lightly equipped when launched and likely forward deployed into locations where the current Batch 2 River-class offshore patrol vessels are stationed, the combination of 57mm and 40mm naval guns will be ideally suited to what will in effect be, at least initially, light patrol frigates.
