H.M.S. Rodney damage

[lwd]

lwd:

OK. Which battleship´s shell could do more damage to another BB than that of Yamato? Let´s assume that those shells impact a ship at the same place, same range. The deck armour, for example...

Well now that you've narrowed the discussion down quite a bit the answer is the US Mark 23 would do a lot more damage than Yamato's shell. Most BB's could survive and even be operational if hit by a single 18" projectile. Not sure you could say that about a hit from a Mark 23.

[Tiornu]

Ooh, trump card! All right, that's true, the atomic shell could do all sorts of damage topside, and though it would likely have had limited effect on the hull of a ship, the damage to the gunnery outfit could be enough to decide the whole issue.
But back within the WWII context, Yamato's shells are supreme.

[lwd]

Well according to the nav weapons site we're looking at 15-20 KT. The explosive charge of a long lance was what around 1T? I suspect the fireball would slag down a significant portion of the hull. A near miss could potentially break even a BB in two. I'd have to do a little more research to have a good idea of just what could happen though.

In a WWII context however I'll agree you are right the least preferred shell to get hit by is one of the 18" ones.

[Tiornu]

Somewhere online, there's a whole bunch of official reports from the Bikini tests. As I recall, Able was an air burst--that's what the 16in shell would give, yes? Such explosions caused little flotation damage but could do a number on superstructures, not to mention crewmen stationed there.

[lwd]

I suspect the 16" round could be set for either air burst, surface (contact), or (less likely) subsurface. If it was an air burst and the fireball didn't touch the ship then I agree it would probably still be afloat. If it was fused for surface or subsurface (this is unlikely). I believe the subsurface fuzing was mostly to go after hardened targets but the navy certainly knew by that point in time what water hammer could do and would have known the limitation of an air burst used against a ship. However I don't have any hard data on this so without a bit more research can't be sure.

Just found some info at:
http://nuclearweaponarchive.org/Usa/Wea ... bombs.html
It states that the fuzzing was time delayed air burst. Not sure how that would have been set or if they had a back up contact detonation available.

[Tiornu]

I would be surprised to hear the atomic mechanism was rugged enough for an impact detonation.

[lwd]

Well some of those on the list I sited above had contact fuzes. That list seams to idicate that the 16" naval round was developed from an 11" army round or some such. I do know that penetrating A bombs were developed to take out missile silos but that may have been after the naval rounds were developed. Just as a guess I suspect that you are correct in that one of these rounds that hit a ship before detonating would be unlikely to achieve a full detonation. I would think they would still have a contact fuze if for no othe reason than to make sure that if something went wrong it would be hard to reconsturct the device. One might well survive impacting the water however. Unfortunatly a lot of speculation with stuff I learned too many years ago playing a major part.

Found some more info at:
http://www.cddc.vt.edu/host/atomic/nuke ... w77b3.html
Looks like the fireball radius for a 20 kt device is about 700 feet and the temperature of the fireball at that point is about 3,000 C. So an airburst set for say a 100 m detonation that detonted over the ship would include the entire ship in the fireball and one that detonated less than 200 m from the ship would probably still include parts of the ship in the fireball.

From:
http://www.cddc.vt.edu/host/atomic/nuke ... w77b1.html

For an air burst of a 1-megaton nuclear weapon at an altitude of 6,500 feet, the Mach effect will begin approximately 4.5 seconds after the explosion, in a rough circle at a radius of 1.3 miles from ground zero.[5] The overpressure on the ground at the blast wave front at this time is about 20 pounds per square inch, so that the total air pressure is more than double the normal atmospheric pressure.

a 20Kt device has about 2% of the energy but would have similar pressures if the burst height was a around 900 feet and would have a radius of effect of roughly the same.

Also stated is:

Strong transient winds are associated with the passage of the shock (and Mach) front. These blast winds (§ 3.07) are very much stronger than the ground wind (or afterwind) due to the updraft caused by the rising fireball (§ 2.09) which occurs at a later time. The blast winds may have peak velocities of several hundred miles an hour fairly near to ground zero; even at more than 6 miles from the explosion of a 1-megaton nuclear weapon, the peak velocity will be greater than 70 miles per hour.

[Karl Heidenreich]

To indulge into a discusion of a nuclear warhead has no point in this thread. Using Bgile´s answer to these kind of arguments, what´s next: a phaser or photon torpedoes from starship Enterprise?

We are talking about conventional combat between battleships. OK? Cordite, AP and HE shells. In this category of ships, guns, admirals, captains, crews and shells produced for naval combat until September 1st 1945 Yamato´s punch is the PUNCH.
After that you can indulge yourself with Godzilla vs. Battlestar Galactica.

Kind regards...

PD: In Japanese anime Science Fiction there is 1970ies TV series about the Yamato resurrected from the bottom of the ocean and transformed into a spaceship that has as main weapon a ray that can destroy an entire planet, like Star War´s Death Star. The series is called "Space Battleship Yamato"...

[lwd]

To indulge into a discusion of a nuclear warhead has no point in this thread.

On the contrary you stated (my emphasis

No ship ever built by mankind could hit as hard as Yamato.

This digression merely showed one way in which this statment was incorrect. Note there are a number of others as well.

We are talking about conventional combat between battleships. OK? Cordite, AP and HE shells. In this category of ships, guns, admirals, captains, crews and shells produced for naval combat until September 1st 1945 Yamato´s punch is the PUNCH. ...

Avoiding hyperbole does keep things more focused. You statement as it stands is still contestable however. Certainly of the WWII naval combatants the Yamato and Musahi had the shells with the most damage potential. They were not however the ships with the most damage potential or for that matter neccessarily the ones with "the Punch". It in the latter case it depends on whether probability of hit comes into consideration.

[Karl Heidenreich]

lwd:

If you are not a lawyer maybe you should consider to go to Law School and later work looking for class action lawsuits...
OK: my mistake about the use of the word "ship". But I believe the rest of the people here, as iankw, understood what I meant. So, let´s be plain clear:

"... no battleship ever built prior September 1945, using conventional AP, HE shells for their conventional guns intended for conventional naval combat at World War Two..."

Happy? I expect you to be so.

[Karl Heidenreich]

lwd:

Certainly of the WWII naval combatants the Yamato and Musahi had the shells with the most damage potential. They were not however the ships with the most damage potential or for that matter neccessarily the ones with "the Punch". It in the latter case it depends on whether probability of hit comes into consideration.

This has been discussed earlier this year...
The Yamato has a much longer range than any of the allied BBs, even with Radar Directed Fire Control. So the Yamato has the first punches against any enemy BBs approaching her. Now, even with RDFC the allied ships straddle/hit ratio (remember that at maximun range it would be plunging fire from the USN and, then, the target a very hard one to hit) at that extreme range would be enormous so Yamato has the edge, because her fire would still have the horizontal component of a less steep impact angle: she´ll be hitting vertical surfaces earlier than her enemies. Radar is of no advantage in this stage: one or two allied dreadnoughts could be gone before the USN or RN would be in a better range. When that happens the allies still would be in disadvantage because the Yamato still has the aiming (the Japanese optics were good ones and there is no reason to doubt about their capability to stradlle quickly).

Well, now I have a 100 mile ride back to my office and a busy weekend so I see you on Monday....

[lwd]

...The Yamato has a much longer range than any of the allied BBs, even with Radar Directed Fire Control.

No. She may have had a longer maximum range but had little chance of hitting anything over about 30,000 yards unless arial spotting was available and even with that the odds on hitting a moving target are low. Thats's without considering crew proficiency. The allied ships using RFC would have a decent chance of hitting at over 30,000 and based on actual evidence as far out as 40,000 yards.

So the Yamato has the first punches against any enemy BBs approaching her.

Clearly not.

Now, even with RDFC the allied ships straddle/hit ratio (remember that at maximun range it would be plunging fire from the USN and, then, the target a very hard one to hit) at that extreme range would be enormous so Yamato has the edge, because her fire would still have the horizontal component of a less steep impact angle: she´ll be hitting vertical surfaces earlier than her enemies. Radar is of no advantage in this stage: one or two allied dreadnoughts could be gone before the USN or RN would be in a better range.

Completly wrong. Radar fire control gives a hugh edge in PH especially over 30,000 yards when optical PH approaches 0. Also consider that the reason both the US and Japan planned on long range engagements is that they considered deck hits to be pottentially more damageing.

If multiple allied BBs are firing at Yamato she would probably have taken multiple hits well before an allied BB was in serious trouble.

When that happens the allies still would be in disadvantage because the Yamato still has the aiming (the Japanese optics were good ones and there is no reason to doubt about their capability to stradlle quickly).
....

If under 30,000 yards you might have a case but of course she didn't really shoot that well off Samar. In addition once she starts taking hits how likely are the optics to stay in good shape? Then of course the allies don't have to allow her the use of her optics as smoke will interfere with them but not radar.

[lwd]

Let's look at some actual numbers from the nav weapons site in regards to the following

......
The Yamato has a much longer range than any of the allied BBs,
... the allied ships straddle/hit ratio (remember that at maximun range it would be plunging fire from the USN and, then, the target a very hard one to hit) at that extreme range would be enormous so Yamato has the edge, because her fire would still have the horizontal component of a less steep impact angle: ....

First of all max range:
Yamato ~46Kyards
Iowa ~42K yards
SoDak ~37K yards
Nelson ~40 K yards

So she can shoot further. However the PH over 40K yards is essentially zero.
Between 30 k yards and 40 K yards the PH without the PH without radar fire control is still essentially 0.

So much for Yamato's range advantage. If the allied ships have RFC they actually have an effective range advantage.

Now lets look at the fall of shot hypothesis.
------- 18.1 - 16/50 - 16/45 US - 16/45 Br
5000 --------- 2.5 ------ 3 --------- 2.5
5470 3.3
10000 ------- 5.7 ------ 6.8 -------- 5.9
10840 7.2
15000 ------- 9.8 ----- 11.7 ------- 10.2
16400 11.5
20000 ------- 14.9 ---- 17.9 ------ 16.5
21870 16.5
25000 ------- 21.1 ---- 25.4 ------ 24.6
27340 23
30000 ------- 28.25 --- 34.1 ------ 33.5
32810 31
35000 ------- 36 ------- 45.2 ------ 43.7

Plot it out and you'll see that the angle of the fall for the 18.1 and 16"/50 are almost identical and the angles vs the other two are not that far off.

[Tiornu]

Yes, we already discussed the angle of descent issue earlier this year and pointed out its limited applicability in this case, but that hasn't prevented its being presented again here as an important factor. At more "normal" ranges, the relationship between descent angle and danger space is much more straightforward. Extreme range changes things.

[Bgile]

The 16"/45 has better performance against deck armor because of it's lower muzzle velocity.

The counterpoint to that is the Yamato would have a higher effective rate of fire due to her shorter time of flight, as would Iowa.

I definitely agree that Yamato's chances to straddle beyond 30kyds are very low.

Finally, the design of the Japanese AP shell was optimized for underwater ballistics at (I think) around 20-25kyds. I suspect it's performance in other circumstances wouldn't be as good as the US AP round, particularly against deck armor.