BAE’s Bofors 40mm Mk4 –Navy Lookout

BAE Bofors 40mm/70 mk4. Click on this to enlarge. Hight of the mount is 1.9 meters or 6.32 feet.

Navy Lookout has what may be the best evaluation of the BAE Bofors 40mm/70 Mk4 mount I have seen thus far. It looks at the 40mm Mk4 in the context of it’s planned installation on the Type 31 frigate, which will also mount the same 57mm Mk 110 gun being mounted on large Coast Guard Cutters (also a BAE Bofors product).

The system can use the same 3P (Pre-fragmented, Programable, Proximity) fuse that can be used with the 57mm Mk110 mount.

Consideration is given to the mount’s role in lieu of a dedicated Close In Weapon System (CIWS). A notable feature is that the 40mm Mk4 is 60% lighter than a Phalanx mount, 5,500 pounds (including about 540 pounds of ammunition) vs 13,600 (2,500 vs 6,120 kg). The Mk38 Mod3 by comparison is 2,300 lbs. (1,042 kg). The DS30M which is apparently expected to be the Mk38 Mod4 is DS30: 2,645 lbs. (1,200 kg) with ammunition.

Compared to the 30mm guns the Royal Navy is currently using, “40-mm weapons offer significantly longer ranges, increased lethal effect in anti-aircraft/missile and anti-surface engagements.”

Effective range is more than doubled and the 40mm projectile is about 2.7 times larger than that of a 30mm Bushmaster II chain gun and more than five times larger than the 25mm fired by the Mk38.

As noted, the 40mm/70 Mk4 has a number of competitors,

“Offerings from other European manufacturers include the Thales/Nexter Rapid Fire CTA 40 (France), Lenardo Marlin 40 (Italy), Rheinmetall Millenium GDM-008 (Germany) and the Aselsan Gökdeniz (Turkey). “

To which I would add the 40 and 50mm chain gun although they currently have no deployed naval mount.

The vessel in the video is 150 tons full load and 36.53 meters (120′) in length, very similar in size to the 153 ton full load Island class cutters. Originally it was a missile boat armed with a 57mm gun and up to six Penguin Anti-ship missiles.

Thanks to Lee for bringing this to my attention. 

SNA Symposium, Virtual Tour

airbus ds trs 4D SNA 217

If you were unable to attend the Surface Navy Association Symposium, but would like to see what you missed, NavyRecognition offers a series of videos. They include a number of systems that have been discussed here including, smart projectiles for the 57mm, unmanned surface vehicles, the LRASM Long Range Anti-Ship Missile, SeaRAM as a replacement for Phalanx, TRAPS Towed Reelable Active Passive Sonar, MK20 Mod 1 Electro-Optical Sensor System (EOSS), TRS-3D Baseline D multi-mode radar (MMR) ordered for the ninth NSC.

If you want to look primarily at the frigate proposals as well as the proposed weapons modules for the LCS which might also be applicable to the icebreaker, there is this composite video. 

Incidentally why was there no mention of this symposium on the National Cuttermen Association Chapter, Surface Navy Association website?


CIMSEC has a new post that is worth the read, “Against the Growing Anti-ship Missile Threat, Are We Truly Semper Paratus?” It is the first of two parts.

Pointing toward the increasing ubiquity of anti-ship missiles, it suggests that we install the SeaRAM system in place of the Phalanx on the Bertholf class National Security Cutters (NSC), and that we also install the system on the Offshore Patrol Cutters (OPC) and the new icebreakers.

With the Commandant’s proposal,  that the new administration send cutters to the Western Pacific to counter Chinese aggressiveness, better self-defense systems make more sense than ever.

Fitting the system to at least a couple of West Coast NSCs that might be available for WestPAC deployment should be relatively straight forward since the systems have much in common with the Phalanx system it would replace. SeaRAM would have the additional benefit of increasing the ships anti-surface capability as well.