Replacing ship's main gun with 155mm artillery?

Most ship today are still armed with the standard Oto Melara 76mm, DCN 100mm, BAe 127mm, or something similiar for its main gun. Recently there have been some developments in replacing the main gun with 155mm artillery:






The German solution, using standard artillery rounds currently avail, can hit targets up to 40 km away. The BAe AGS (Advanced Gun System), with the LRLAP (Long Range Land Attack Projectile) claims range up to 109 km. Modern artillery are highly accurate, and the extended range allows you to do shore bombardment from further distance away.

If the main offensive arament of ships today is anti-ship missiles, and ship guns have been reduced to secondary shore bombardment duties, would it be better to simply replace the guns with 155mm artillery, which can be used against other ships if needed? Or is there still some benefit of retaining the existing guns?

Or, alternatively, for ships dedicated to air defense roles within a fleet, to simply replace the main gun with 30mm CIWS system, or additional VLS launch cels?

The thing is that most of the modern naval guns are DP guns with high rate of fire. Both these features cannot be achived with 155m guns orginally intended for field artillery role. 155m guns ammunitions haven't got shellcasing and the ammunition (piggie) is a separate particle and the gunpowder is in bags which you load after the ammunition is stucked to the tube. Most modern Naval guns however has a riflecartidge type of munitions with shellcases and all...

Dear Sirs:

If I remember correctly, traditional heavy naval guns (greater than 6 inch - 153 mm caliber) are typically bag-charged. The projectile was first loaded, then rammed, after which the required number of powder bags (looking rather like giant pillows) were then loaded into the chamber.

Ignition was usually electrical, and to aid this gunpowder charges were stitched onto the ends of the powder bags. Sealing the chamber (obturation) was done by a mushroom-shaped piston acting upon a seal ring. When the gun fired the high pressure would compress the ring, expanding it's circumference, sealing the chamber.

One of the limitations (aside from those mentioned in the articles posted) would be the rate of traverse and elevation - which are slower in a land system. Another would be the limited amount of elevation available. All this would limit the systems' usefullness against aerial or fast-moving targets, reducing its role as a dual-purpose gun.

Given enough power, I suppose the training rates could be increased, however, how much that could be improved for a piece of artillery like a 155 mm gun is debateable. That is a pretty heavy piece of metal to swing rapidly about.

If sustained fire is required, then typical naval modifications like water-cooling and air-purging must be made. Rapid replacement of the barrel would also be called for.

The kind of long-duration, maximum rate-of-fire bombardments undertaken by navies is unusual in land-based field artillery operations. Our own fire-missions (with ex-US WWII 105 mm howitzers) were seldom done at the gun's maximum fire-rate.

The resultant weapon would end up firing specialized guided ammunition for the majority of it's fire missions - land, sea or air. I foresee a tremendous increase in the cost of such ammunition - ending up with a piece that is more like a glorified missile launcher.

Would such a weapon ultimately justify the fanstastic increase in cost over conventional naval artillery with more modest technical improvements? I think not.

In the end, navies kept the gun because it was the most economical way to engage a wide variety of targets effectively - something that given the history of US guided projectile developement is unlikely to be achieved.

What is much more likely to happen is that the US Navy will once again find the most expensive way to arm its' ships with guns.

Best Regards,

Dusky Lim

Another point to remember is that modern Naval guns are quite different from land artillery pieces, inasmuch as they are fully automatic weapons operated from the CIC. Nobody is in the gun mount, indeed there is no room for anyone in the gun mount other than for maintenance. In the Falklands war the British 4.5inch (114mm) mk8 single and mk6 twin mounts were reckoned to achieve a rate and weight of fire comparable to a six gun land battery equipped with 105mm guns. The mk8 is a very reliable weapon having been in service for over thirty years, and the trend towards heavier guns has seen the mount proposed as the basis for a 155mm weapon for the new type 45 Daring class DDGs. It could also be retro fitted to any ship mounting the mk8 in theory, and as it was widely exported that could mean orders from abroad too.
The 155mm Naval gun would use essentially the same barrel as the army's gun, but would have to use rifle cartridge ammunition in order to be compatible with the auto loading system so a common supply of ammo with the army isn't possible.

Well, if you want to shoot down AC then its 5 inch or 120mm. If you want to sink ships its 6 inch or 150 mm. All durring WW2 the Allies were trying to get a good 6 inch AC gun. They never did it and still have not. Most people dont realize the big difference between a 5 inch and 6 inch shell. A 5 inch is about 80lbs and 6 inch is over 240lbs.
The Japanese tryd to shoot 18 inch anti AC shells out of the Yamato ( or sister ship- forgot name) and blew out it turrents- (reported, not confirmed).

This forum is unbiased and internationally friendly, so let's not use contractions that can result in misunderstanding.

Dear Sirs:

The representative projectile weights of a 6 inch weapon (about 155 mm) would range from 45 to 50 kilograms (thats about 90 to 100 lbs approximately). A 5 inch weapon (127 mm) would have about 25 kilogram round (about 50 to 55 lbs approximately).

Armour-piercing rounds would be heavier, while high-explosive rounds would be lighter. Of course to pierce ship armour at long range, the heaviest shell is the best one.

It its final series of WWII light cruisers, the Worcester class, the US Navy introduced what was the most potent of 6 inch naval weapons, the 47-caliber, Mk 16 Dual Purpose gun. Unfortunately these cruisers were too late to serve in the War.

It was an excellent weapon, capable of being loaded at all elevations! The new all-power turret could be trained and elevated more rapidly than any previous models. It was considered an excellent AA weapon, more effective than the previous 5-inch 38-caliber it replaced.

The round that the Japanese developed for firing against aircraft is called the san kai dan. It was a form of AA shrapnel. The 1.3 ton shell was filled with bomblets and was timed to burst about 1000 meters from the gun. Bad fuzes could set it off inside the barrel with terrible consequences.

Best Regards,

Dusky Lim

dusky
You are right on. I am going back and trying to find where I got my bad info on the web. Will do my best to give you a link- thanks for the correction.

Well, if this gun fails as a lone DP gun on a ship, then why would the US and Germany switch o the 155mm? (Or do you think it is a mistake?)

Looks like I was looking at the actual turrent and not the shell- my bad.

Data is for Bismark

Twin Mounts:
116.250 kg (256.287 lbs.) including range finder
110.000 kg (242.500 lbs.) without range finder
108.000 kg (238.100 lbs.) without range finder and short barbette

I have nothing against this idea but, what is the use for a gun? Guns on ships these days are litterally useless. Against enemy ships, you use torpedos. against land targets, you use cruise missiles. Features that every modern warship has.