BAE/RO 155mm Naval Ordnance

[JFC Fuller]

BAE Third generation Maritime Fire (TMF) support gun presentation, courtesy of DTIC, attached. This contains all of the images commonly seen online plus many more, and gives a good overview of how the TMF mounting and loading mechanism would have been adapted from the 4.5" Mk.8.

 

[JFC Fuller]

Twitter thread from @RP1 on the Royal Ordnance ERO 155mm/52 naval gun.

https://twitter.com/x/status/1666552245247176704

View: https://twitter.com/R_P_one/status/1666552245247176704


Variants:

Single barrel (Generic Naval Turret): Automatic magazine designed for the Type 45, separate ammunition but a loading tray long enough to ram an extended range munition and propellent charge in one go. Weight was to be 26 tonnes.

Revolver (Enhanced Target Effect): Twelve chamber revolver, 6 chambers for shells and 6 for propellent, with a centreline rammer that would have allowed for a firing rate of 6 rounds in 10 seconds. The revolver magazine would be reloaded at an elevation of 55 degrees. Presumably the reload would take 10 seconds too, allowing for three 6 round cycles in a minute to deliver the stated 18rpm.

Twin mounting (Maximum Target Effect): Presumably a twin mount version of the revolver variant to deliver the 36pm required for 72rpm from a ship with two mountings.

The 155mm precision guided round is almost certainly related to the Low Cost Guided Munition project discussed in this thread, note what appears to be space for three submunitions.

 

[timmymagic]

Quite interesting how much better the 4.5" shell performs compared to 5" in slide 7....a dramatic difference.

 

[Scott Kenny]

I still don't get why the Brits (and USN for that matter) haven't gone to 155mm and able to load NATO standard shells on ships.

One less chunk of logistics you need to supply, and the larger buys of ammunition get you cheaper prices.

 

[MihoshiK]

I still don't get why the Brits (and USN for that matter) haven't gone to 155mm and able to load NATO standard shells on ships.

One less chunk of logistics you need to supply, and the larger buys of ammunition get you cheaper prices.

Because
A: When the Navy is through with it it's not a NATO standard shell any more, at least not the seperate drive charge. Naval demands on munitions safety are different from Army demands.
B: Naval gunfire support for boots on the ground is dying out. Cannons simply do not afford the stand-off capability needed any more, and besides, if the Marines have to go over a contested beach, it's likely someone (you) has made a tactical error.
C: Large calibere guns are terrible at fending off a swarm of shitty little boats. The USN went to 57 mm for the FFX not because there wasn't room for a bigger gun, but because they thought it would be more useful. With airbursting munitions it can even double as a CIWS.

 

[Scott Kenny]

I still don't get why the Brits (and USN for that matter) haven't gone to 155mm and able to load NATO standard shells on ships.

One less chunk of logistics you need to supply, and the larger buys of ammunition get you cheaper prices.

Because
A: When the Navy is through with it it's not a NATO standard shell any more, at least not the seperate drive charge. Naval demands on munitions safety are different from Army demands.
B: Naval gunfire support for boots on the ground is dying out. Cannons simply do not afford the stand-off capability needed any more, and besides, if the Marines have to go over a contested beach, it's likely someone (you) has made a tactical error.
C: Large calibere guns are terrible at fending off a swarm of shitty little boats. The USN went to 57 mm for the FFX not because there wasn't room for a bigger gun, but because they thought it would be more useful. With airbursting munitions it can even double as a CIWS.

A: Granted on the propelling charges. So? You are still buying hundreds, if not thousands, more rounds which drives the per-unit costs down. Couple hundred shells per tube per ship adds up even when the total British fleet has 25 guns.

B: So why is everyone trying to make 100+km cannons for ships? 155mm/58 on charge "super" makes for a 70km range from M982 Excalibur or M795 base bleed, without using rocket assisted shells. Or the XM1113 rocket assisted shell beyond that. Though personally I'd expect Excalibur HTK being the primary naval round. Guidance package of the GBU-53 Stormbreaker and an armor-piercing warhead, for all weather operations.

C: The 57mm has an excellent rate of fire, and it actually throws a greater weight of shell per minute than anything less than the 5"/54. But if you're worried about swarming small boats, stick a couple of 25mm or 30mm Bushmaster cannons on there. Or even some 35/50mm Bushmaster IIIs, since the 35/50mm can easily take AHEAD type ammunition.

 

[TomS]

B: So why is everyone trying to make 100+km cannons for ships? 155mm/58 on charge "super" makes for a 70km range from M982 Excalibur or M795 base bleed, without using rocket assisted shells. Or the XM1113 rocket assisted shell beyond that. Though personally I'd expect Excalibur HTK being the primary naval round. Guidance package of the GBU-53 Stormbreaker and an armor-piercing warhead, for all weather operations.

Vulcano isn't exactly "everybody." I can't think of any other extended-range naval rounds in development right now.

The issue with things like Excalibur is that the baseline Army round isn't HERO safe to Navy standards. Getting better, becuase the land battrlefield is a lot more electronically dense than it used to be, but not there yet. So when they did pitch Excalibur for the US Navy as N5, for example, it was an all-new round (127mm and reworked for HERO safety). N5 doubles the range of conventional 127mm, which gets out to ~50 km. But that still gives either very little standoff from the beach or very little reach inshore.

But if you're worried about swarming small boats, stick a couple of 25mm or 30mm Bushmaster cannons on there. Or even some 35/50mm Bushmaster IIIs, since the 35/50mm can easily take AHEAD type ammunition.

Not enough reach or stopping power. One 25mm hit isn't a guaranteed boat-stopper, one 57mm hit is.* And 25-30mm or even 35mm really can't outrange MRLs on an Iranian FIAC. Going to 57mm gives you entrée into proper guided rounds (Alamo now, MAD-FIRES maybe later) which changes the effective range calculus significantly.


* OK, not guaranteed, because nothing is, but the Pk for 57mm is way, way better.

 

[Scott Kenny]

B: So why is everyone trying to make 100+km cannons for ships? 155mm/58 on charge "super" makes for a 70km range from M982 Excalibur or M795 base bleed, without using rocket assisted shells. Or the XM1113 rocket assisted shell beyond that. Though personally I'd expect Excalibur HTK being the primary naval round. Guidance package of the GBU-53 Stormbreaker and an armor-piercing warhead, for all weather operations.

Vulcano isn't exactly "everybody." I can't think of any other extended-range naval rounds in development right now.

The issue with things like Excalibur is that the baseline Army round isn't HERO safe to Navy standards. Getting better, becuase the land battrlefield is a lot more electronically dense than it used to be, but not there yet. So when they did pitch Excalibur for the US Navy as N5, for example, it was an all-new round (127mm and reworked for HERO safety). N5 doubles the range of conventional 127mm, which gets out to ~50 km. But that still gives either very little standoff from the beach or very little reach inshore.

BAE pitched Excalibur N5 because almost all USN ships are armed with a 5" gun. There's no reason they couldn't make the 155mm version HERO safe.

But if you're worried about swarming small boats, stick a couple of 25mm or 30mm Bushmaster cannons on there. Or even some 35/50mm Bushmaster IIIs, since the 35/50mm can easily take AHEAD type ammunition.

Not enough reach or stopping power. One 25mm hit isn't a guaranteed boat-stopper, one 57mm hit is.* And 25-30mm or even 35mm really can't outrange MRLs on an Iranian FIAC. Going to 57mm gives you entrée into proper guided rounds (Alamo now, MAD-FIRES maybe later) which changes the effective range calculus significantly.


* OK, not guaranteed, because nothing is, but the Pk for 57mm is way, way better.

That's why I went up to 35/50mm. 50x228 or even the Army 50x319 CRAM round, though that requires a Bushmaster IV receiver.

 

[TinWing]

Twitter thread from @RP1 on the Royal Ordnance ERO 155mm/52 naval gun.

https://twitter.com/x/status/1666552245247176704

View: https://twitter.com/R_P_one/status/1666552245247176704


Variants:

Single barrel (Generic Naval Turret): Automatic magazine designed for the Type 45, separate ammunition but a loading tray long enough to ram an extended range munition and propellent charge in one go. Weight was to be 26 tonnes.

Revolver (Enhanced Target Effect): Twelve chamber revolver, 6 chambers for shells and 6 for propellent, with a centreline rammer that would have allowed for a firing rate of 6 rounds in 10 seconds. The revolver magazine would be reloaded at an elevation of 55 degrees. Presumably the reload would take 10 seconds too, allowing for three 6 round cycles in a minute to deliver the stated 18rpm.

Twin mounting (Maximum Target Effect): Presumably a twin mount version of the revolver variant to deliver the 36pm required for 72rpm from a ship with two mountings.

The 155mm precision guided round is almost certainly related to the Low Cost Guided Munition project discussed in this thread, note what appears to be space for three submunitions.

Untitled Document

Anthony G. Williams makes a reference to a turret weight of 29.5 tonnes for an 18rpm BAE gun, which I presume to be the same as 18rpm revolver option listed above. He also hypothesized water cooling.

He also mentioned a 1988 proposal for a joint FMC/Vickers/OTO 155mm for the NFR-90 in another article.