Duel of the Imbeciles: Alaska vs. Tirpitz

Actually, I don't think that would work. The German "Pocket" battleships were intended as commerce raiders, their fire control was unable to track multiple fast moving ships...Bismark could, her fire control was able to track and engage multiple targets if needed, though generally normal doctrine for all navies was to engage one target at a time with its main battery.
 
Tirpitz has 320mm of belt armor, which the 12"/50 on the Alaska class can penetrate at 20,000 yards (18.2 km). Its deck is 120mm thick, which the 12"/50 can penetrate above 30,000 yards (27.4 km).

Getting shells through the Tirpitz's belt can make a mess of the upper deck and probably the ventilation for the boilers, but penetrating the sloping armour deck in addition, to get to a turbine/boiler room or magazine, would be much harder.

A diving hit from long range going under the Tirpitz's belt, like POW achieved at DS, might be dangerous, although the lesser energy of the 12", realtive to the British 14", might make it difficult to to serious damage.

Scharnhorst would be a much more interesting comparison...
 

CalBear

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Best thread title of 2015!

:D

The Alaska 12"/50 was an exceptional gun (unfortunately it was placed on the Alaska class). It actually had better armor penetration that the 14" gun on the British KGV class BB, a gun that was demonstrated as being effective against the Bismarck class. The USN ship can, especially at range, hurt the bigger battleship.

The Tirpitz, however, can also rip up the smaller, less well armored CB at just about any range. The American ship has a speed advantage, but handles poorly at maximum speed (30K tons and ONE RUDDER? Seriously??!!). By the time of any possible engagement American gunnery was remarkably accurate thanks to years of perfecting the radar direction of the guns (which is fortunate since the BC has it best chance to survive by keeping the engagement at 30K yards or more). Bismarck, however, demonstrated considerable accuracy in its single engagement, that engagement was, however mainly fought by Bismarck at 15K yards or less.

Bottom line here is that the Tirpitz needs to be lucky. If it manages a couple 15" hits and slows the Alaska to below 27 knots it will not end well for the CB. If the American ship can keep the range up and maneuver well enough to avoid being zeroed, it can do some damage. In the best case the U.S. ship can cripple the BB, sinking her may be a bridge too far (Bismarck took a total of 400 gun hit of various calibers, from 8" all the way to 16", and didn't sink). Since the Alaska's never suffered significant battle damage their survivability is unknown.

As likely as not the two ships beat the hell out of each other until they are both scrap.
 
And there goes my hope that this was a TL about a case called The State of Alaska vs Alfred von Tirpitz, that had somehow been labelled Duel of the Imbeciles in the press.
 

hipper

Banned
Best thread title of 2015!

:D

The Alaska 12"/50 was an exceptional gun (unfortunately it was placed on the Alaska class). It actually had better armor penetration that the 14" gun on the British KGV class BB, a gun that was demonstrated as being effective against the Bismarck class. The USN ship can, especially at range, hurt the bigger battleship.

As likely as not the two ships beat the hell out of each other until they are both scrap.

I think you are incorrect on the bolded statement

the RN 14" weighed 400 lbs more than the 12" shell and was only 13 ft ft/second slower compared to the American gun when both guns were new.

2483 ft/sec vs 2500 ft/sec

as you would expect the heavier shell has a higher penetration

as can be seen from Nathan Okuns Facehard program at the link below.

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


Both ships are only vulnerable to Deck penetrations at ranges over 30,000 yards

Alaska is vulnerable to main belt penetrations at all ranges

Bismarck's Main belt is only penetrate able by Alaska at ranges under 10,000 yards

so if the two ships beat the hell out of each other then Alaska is taking a risk of magazine explosion in every exchange of fire

Cheers Hipper
 

Saphroneth

Banned
The 12" was better than the US's previous 14", as I understand it... but that was a (very early) 1920s weapon IIRC.
 
The 12" was better than the US's previous 14", as I understand it... but that was a (very early) 1920s weapon IIRC.

UK MkVIIB 14" APC 1590lbs 338lbs charge 2400fpsMV 15,000yards 13.2" 1.95"deck penetration penetration at 20,000yards, 11.2"belt and 2.85" deck penetration 2rpm


USN Mk10 14" APmk20 1500lbs 425 lbs charge 2600MV 14800yards 16" 2" deck 18,800yards 14" 2.5" deck. 1.75rpm

USN Mk8 APmk18 1140 lbs 275 lbs charge 2500fpsMV 15000yards 15.6" 2.1" deck 20,000 yards 12.7" belt and 3" deck 2.4-3 rpm

KM 15" APC 1764lbs 374lbs charge 2690MV 19685k yards 16.5" belt 2.96" deck 2.3-3 rpm

The 12" was better than the 14Mk10 in Rof, but less belt penetration at longer range, but is better across the board over the RN 14"
 

CalBear

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I think you are incorrect on the bolded statement

the RN 14" weighed 400 lbs more than the 12" shell and was only 13 ft ft/second slower compared to the American gun when both guns were new.

2483 ft/sec vs 2500 ft/sec

as you would expect the heavier shell has a higher penetration

as can be seen from Nathan Okuns Facehard program at the link below.

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


Both ships are only vulnerable to Deck penetrations at ranges over 30,000 yards

Alaska is vulnerable to main belt penetrations at all ranges

Bismarck's Main belt is only penetrate able by Alaska at ranges under 10,000 yards

so if the two ships beat the hell out of each other then Alaska is taking a risk of magazine explosion in every exchange of fire

Cheers Hipper
Recommend you look at the individual weapon data on Navweaps. There is more than just weight or velocity to be considered, the design of the shell, especially how difficult it is to decap, is a critical consideration
 
And whether the shell detonates- if we allow realistic settings, the German shells had a higher dud rate. Not sure if they ever fixed that problem (or even knew about it till after 1945).
 

hipper

Banned
Recommend you look at the individual weapon data on Navweaps. There is more than just weight or velocity to be considered, the design of the shell, especially how difficult it is to decap, is a critical consideration

this is an interesting example of an Echo chamber effect where poorly presented information misleads and causes people to come to incorrect conclusions.

Simply put the muzzle velocity figures quoted on the individual weapon data tables for the Royal Navy are for guns at 25% of service life. While muzzle velocities quoted for the U.S. Navy are quoted for New guns. naval guns loose a little muzzle velocity every time they fire.

the effect of this is to ireduce the armour penetration figures for RN guns compared to other navies.

Re shell design late war American naval shells had blunter points giving them better penetration at higher angles of impact British shells had sharper points making them better penetrators at low angles of impact

The ability of a shell to resist decaping says nothing about the raw armour piercing capability of a particulat shell,
there has to be a decaping layer present at the target.

in any case a larger caliber shell will resist decaping better than a smaller caliber in all but a small minority of shell types.

The data I linked to on the navy weapons site gives a better view of the real state of things and makes the situation clear

at 20,000 yards the RN 14" gun has a penetration of 15.3 inches of British armour

While the 12" USN gun has an armour penetration of 11.6 inches of British armour at 20000 yards



Regards Hipper.
 
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