Yamatos Type 94 46cm/45 guns

These are often regarded as the most powerful guns ever installed on a battleship, yet I've also heard they were mediocre for a gun of its caliber, has anyone else heard of this, and could please elaborate on this?

 

One bit of trivia, it did not fire the heaviest shell, that was the British 18"40 on HMS Furious and a couple of monitors in WWI, 3320lb vs. 3219. However the muzzle velocity of the 18.1"/45 was greater.

For its size, it did not fire a particularly heavy shell. Just going by caliber, and keeping in mind that shell weight is proportional to the cube of caliber, one would expect an 18.1" to be about 45% heavier than a 16". In fact it was only about 44% heavier than the 16" on older ships like Colorado or Nagato and just 19% heavier than North Carolina or Iowa.

No doubt we'll have considerably more detail when the experts weigh in.

 

Here is a great link on battleships:

http://www.combinedfleet.com/baddest.htm

Drill down to the gun section:

http://www.combinedfleet.com/b_guns.htm

GENERAL COMMENTS: The Japanese 18.1"/45 reigned supreme as the most destructive piece of naval ordnance ever mounted afloat. However, its ballistic performance was not particularly inspiring, and the performance of its Type 91 shells was inferior to the norm, partly because they were optimized for underwater trajectories 7. Immediately below it in terms of power is the US 16"/50. Good ballistics, and superb shells, give this gun a tremendous whallop, and in combat terms I rate it as the equal of the Japanese weapon, largely because of its shells. Below that, in an upset, comes Richelieu's 15"/45, as the best all-around 15" gun, and feel the most useful in an actual combat situation. The Italian 15"/50 was an enormously potent weapon from a raw power perspective, but it sacrificed a lot in order to achieve that performance, and had decidedly inferior shells. I should note, though, that I am still investigating this particular gun and her shells in more detail; the information available on her shells is rather spotty. Bismarck's 15"/47 shell is 10% lighter than the French and Italian, although her cyclic rate is attractive, and her guns were very accurate. At the bottom of the spectrum, King George V's 14" gun clearly doesn't have nearly the oomph necessary to compete with the rest of these guys.

 

That helps explain things a bit, thanks you two.

 

navweapons is also a good place to at least start. They usually mention their sources as well so you can find more detailed info. I'm pretty sure there is a section from the naval technical mission (which is on line in a couple of places) that goes into these weapons as well.

 

Yeah LWD I love the navweapons site. Tons of good stuff there.

Direct link to the Type 94 46cm/45 gun and mount.

http://www.navweaps.com/Weapons/WNJAP_18-45_t94.htm

There is also some limited information on the 20.1in/51cm gun planned for the Super Yamato's. Apparently two guns and one mount were actually manufactured at Kure prior to the outbreak of war with the west.

http://www.navweaps.com/Weapons/WNJAP_20-45.htm

 

Navweaps and Combindedfleet are great sites indeed, my one quibble with navweaps regarding Yamatos guns is the armor penetration specs, it just shows armor penetration at 0 yards, 21,872 yards, and 32, 808 yards versus the US Mk. 6 and Mk. 7 16," which shows all ranges, so you can't really compare Yamato and Iowas performance at ranges at say 5,000 yards.

http://www.navweaps.com/Weapons/WNJAP_18-45_t94.htm

http://www.navweaps.com/Weapons/WNUS_16-50_mk7.htm

 

They do have the link to via the technical forums to Nathun Oakun's site which has the following table:
http://www.navweapons.com/index_nathan/Penetration_index.htm
It has pretty detailed penetration tables under the respective national titles based on his armor penetration program. Increments are 2000 yards from 0 out to max range and for a number of different types of armor and different definitions of penetration.

 

True, 14 is smaller than 15,16, or 18, but penetration of belt armor was not as critical as people had expected (granted there is a small database of engagements between modern battleships). One of the most critical hits of the war was Prince of Wales' 14" through the bow of Bismarck - not only did it compel her to abandon her mission and head for France, being down by the bow forced her to steam in the wrong direction after she lost steering control - northwest, into the wind and seas, and back towards her pursuers.

 

You forgot to mention that it also cost her rather critical fuel oil as well. Put KGV in either of the other Pacific battle ship engagements and I suspect she does as well as the US battleships involved. At 5,000 to 10,000 yards those 14" rounds are going through Kirishima almost as easily as Washington's 16" ones and the British 14" AP rounds actually carried a larger burster than the US super heavy 16" rounds. The extra gun likely means more hits as well. At Surigao the KGV would likely have been a contributor as well unlike most of the US BBs with the older FC radar.

The one time that the true advantage of the penetration of the US 16 super heavy was evident was off in Torch where fortunately for both sides the 16" round the found Jean Bart's Magazine also found it empty.

 

That is a great point.

 

Unfortunately the link is not working.

 

http://www.navweaps.com/index_nathan/Penetration_index.htm

 

Much better, thanks Takao!

 

For some reason I can't paste things into my responses on this machine. I try hand typing but it doesn't always work even though I try and make sure I typed it right. Someone usually finds it though (Takao more often than not - thanks by the way). If you haven't looked at the technical page there are some very worthwhile articles there although some may not be the most current. Nathun Oakun's pages are worth looking through as well, some of the information may be more technical than you want but that's easy enough to skip over and come back to it if and when you are more interested.

 

imagine if the war dragged on and 20-inch gun battleships had to be fielded.

 

Found this on youtube - a Japanese produced animated tour of a Yamato turret showing how the mechanical systems operated. Nice detail.

Now only if I could read Japanese..

www.youtube.com/watch?v=9T3rvxlz03U

 

That is great. I think Iowas still had the crew members carrying the powder bags from the lift to the loading tray. The Yamato loader looks more automatic.

 

There's a very detailed account on how the Iowa class guns were served on line. I think there's a link to it somewhere off the navweapons site.