Teleportation in time: Bismarck swap with IJN Yamato

Historical what if discussions, hypothetical operations, battleship vs. battleship engagements, design your own warship, etc.
alecsandros
Senior Member
Posts: 4349
Joined: Wed Oct 14, 2009 2:33 pm
Location: Bucharest, Romania

Teleportation in time: Bismarck swap with IJN Yamato

Post by alecsandros »

Alot of topics online concern the unfortunate Rheinubung mission, with many posters mentioning "other" contemporary battleships as behaving better then Bismarck.

I propose writing about several of them, and to explore the possibilities.

1) IJN Yamato, almost completed , is teleported back in time , in Kiel, Aug 1940. The comissioning ceremony is governed by Hitler, and the crew starts embarkation in Sept 1940.

Fast forward to May 1941: Yamato with PRinz Eugen starts the journey to the Atlantic.

As Yamato's top speed is 27.5kts, and economical cruise speed is 15kts, the force is required to travel at 20kts. At that speed, Yamato's range is around 9000km, versus 14000km for Bismarck. It means it is enough to get to the mid-Atlantic (about 3500-4000km travel), but it would require refueling once there, in order to conduct operations and to be able to get back home.

That means the force will require 25% more time in order to travel the same distance as Bismarck did (Bismarck averaged 25.5kts or so before being discovered by Norfolk). So northern entry in the Denmark Strait around May 24th 7:00, in full daylight. Both cruisers do contact and mantain it. Yamato's nonexistence of radar makes tracking them difficult, leaving Prinz Eugen to track them , while supervising the radar horizon for potential threats as well.
Yamato's max speed limit of 27kts makes attempts of escape irrelevant.

As contact report is received by Holland at ~ 7:30AM, he manovres his 8 ships (Hood, Prince of WAles, 6 DDs), to the north-west, in order to seal off the southern end of the strait. He disposes the 6 DDs in a 30km long battleline crossing the entire exit of the strait, with Hood/Prince of Wales immediately behind the center destroyres.

Yamato exits the strait at ~ 20:00PM, and is observed by 2 of the destroyers, that send contact reports. Holland orders simultaneos torpedo attacks from all 6 DDs, while Hood/PoW stay in line abreast, with all main turrets trained towards the expected appearance of the enemy. Yamato discovers Hood at 20:20, from the top of the main mast, range ~ 35km. All guns are loaded, alarm is sounded, speed raised to maximum. The destroyers are observed between 20:25 and 20:30, while they work up speed. Prinz Eugen is tasked with blocking the destroyers, while Yamato manouvres to open the arcs of the aft main turret, in order to engage both Hood and Prince of Wales at the same time.
At 20:35, speed on Yamato reaches 24kts. Yamato opens fire on Hood from range ~ 25km. Hood is doing 25kts , and returns fire immediately. Prince of Wales follows shortly.

As first salvos from Yamato fall very close to Hood, the first destroyres enter Prinz Eugen's artillery barrage zone (also helped by Yamato's secondaries). The destroyers launch 16 torpedoes in 5 minutes, all aimed at Yamato. Yamato immediately starts evasive manouvres. One of the DDs is struck by a 203mm salvo, and puts a smoke screen to retreat at reduced speed. The other 4 DDs attack at 35kts, under fire from the enemy ships.

Hood and Prince of Wales straddle Yamato from 20km , while the Japanese BB is still running away from the first torpedo attack.

Prinz Eugen badly damages another destroyer, but the other 3 launch another set of 20 torpedoes against multiple possible courses of Yamato, from range 8km. In the mean time, Prince of Wales had closed to 16km from Yamato, and hits her 2 times in the superstructures.

Yamato returns fire for about 2 minutes, obtain 1 hit on the forward main turret of PoW (turret which is destroyed), after which it returns to doing evasive manouvres, acting on the alarm of torpedoes.

Hood concentrates on Yamato as well, and lands 2 hits in 3 minutes, from range 17km. One of them destroys the main rangefinder, the other exploes in the forecastle, which starts taking water. Speed is reduced to 22kts, while the torpedoes approach. ONe hits the stern, causing 2000tons of water to enter the ship. Speed drops to 20kts.

Main targetting system is damaged by the shock of the blast. Prince of Wales and Hood concentrate all guns on Yamato, and hit her 10 times in 10 minutes.

Prinz Eugen returns fire and hits Hood multiple times, damaging the foretop. Yamato returns fire innefectively. Yamato's topside burns, but the ship continues to fight. One lucky 18" shell hits Hood's con tower, which explodes.

As the initial phase of the battle rages, from the north , Suffolk and Noroflk charge. They both target PRinz Eugen, which is hit from 15km, and forced to put a smoke screen, and return fire to them. Suffolk is hit.

As twillight sets in , by 21:30, both forces retreat, unable to decisively destroy the enemy.

----

Tovey's force is coming from the east. By May 25th, Yamato's speed is stabilised at 15kts. Only 1 main turret still functions on local control. Prinz Eugen , damaged, guards her rear. Both ships attempt retreat back through the strait.

KGV with Repulse and Prince of Wales join forces at 11:00AM May 25th, and start pursuit through the strait.

As Yamato crosses the strait, it detonates 1 mine, which causes more damage to the stern. One propeller is destroyed, one rudder jammed. Speed drops to 10kts.

At 14:00, through fog, at range ~ 8km, the 2 forces spot each other and open devastating close-ranged fire.
Yamato is hit repeatedly from 10-15-20 x 14" shells and is an inferno. 1 x 18" hit from the single working turret perforates deep inside KGV, and explodes in the machinery space, causing 50 dead and speed reduction to 18kts.

Prinz Eugen is targeted by Repulse. In 10 minutes, both ships hit each other 4 times. Prinz Eugen is set ablaze, Repulse has fires and dead on board, but manageable.

IN 10 more minutes, the battle is over - Yamato dead in the water, scuttled. Prinz Eugen sinks.
guest

Re: Teleportation in time: Bismarck swap with IJN Yamato

Post by guest »

I personally find this simulation to be very strange.

Your simulation assumes multiple things go wrong with Yamato and almost everything goes right for the RN.

I'll break this down into segments:

Fire control:

Yamato's fire control was not in any way shape, or form, bad, certainly no less accurate than other navies yet you seem to grant her much lower hit rates than that of the RN. In your simulation, the RN lands multiple crippling hits while Yamato lands all of 2 hits. This seems very lop sided and implausible. Yamato did not have a lower rate of fire than other battleships as commonly believed, she would have output a steady 9 rounds every 30 seconds for as long as she fired. While the British had more heavy guns and could statistically score more hits due to the 9 extra guns giving Yamato 2 hits and the British an upwards of 20 is simply absurd.

RN ships straddling from 20km? Considering Hood was shooting way off historically and PoW did not straddle until her 6th salvo at 18km - with her type 284 radar no less, straddling Yamato that is actively maneuvering to evade torpedoes? How? Are we giving the RN in 1941 Iowa's 1944 radar outfit that was able to predict and straddle (forgot name of ship) a certain IJN ship from beyond 30,000 yards?

Then we have the 6 destroyers that are somehow able to close to 8km under fire from 8x8" from PE and 12x6" from Yamato. The idea of those 6 destroyers coming through unscathed is a bit far fetched. Acasta and Argent were heavily hit trying to close the range to Scharnhorst and Gneisenau and were later sunk by those same secondary batteries. That Yamato's secondaries in your simulation make zero impact on the outcome, that they are unable to score even a single hit is rather implausible.

PoW closing to 16km? What is Yamato doing all this time? Sitting idly by and waiting to be sunk? So PoW somehow lands 2 hits from 16km while Yamato lands all of zero? What are the chances of that? Keep in mind that Admiral Holland had ordered PoW to follow the flag and not make independent maneuvers. This order stayed until Hood exploded. PoW would not have been able to independently maneuver throughout the battle while Hood was still around. If PoW is at 16km, so is Hood, at 16km, would Hood last long under 18" fire? Highly doubtful unless we are using these hit rates in which case Yamato misses every single salvo she fires.

Torpedoes at 16-20km? British torpedo range was roughly 12km max, why would they be launching outside their max range? Did the British get Long Lances as well in this simulation? If Yamato is running away from the first torpedo attack at 16km, exactly how did the destroyers close to 8km to launch their second? What was PE doing and what were Yamato's secondary batteries doing? Sitting idle again?

Damage:

The RN weapons would be unable to cause any meaningful damage to Yamato outside of her superstructure and the unarmored bow and stern of the ship. The 14" and 15" are simply put, completely out classed by the 16" that Yamato's armor was designed to withstand. As for Yamato's turret and barbette armor, even her own 18" would have had to have been placed within a distance of 3km to have any chance of penetration. Yet somehow Yamato loses 2/3 of her main turrets to 14" & 15" fire? How?

On the other hand, how does the 18" hit from Yamato on PoW's forward turret not destroy the ship? There is an awful lot of combustible material inside a turret and the 18" shell would not have simply detonated inside the turret, the penetrating power of that shell would have drove it into a magazine before exploding - with obviously disastrous results. PoW's turret and barbette armor would have been unable to stop even a 15" hit from Bismarck, never mind an 18" hit from Yamato!

An 18" hit to Hood's conning tower would over penetrate without much damage.

Visibility:

How is a destroyer able to spot Yamato and PE without being spotted in turn? Keep in mind PE had both radar and hydrophones and historically, it was the latter that picked up Hood and PoW as they were closing in long before they entered visual range. A destroyer is far lower in the water than either Yamato or PE and would have a significantly harder time spotting anything due to this. Yamato on the other hand would have had a far easier time spotting approaching ships at long range.

--

The first part of the engagement already makes so little sense that the second part can be discounted.

Your usage of the words "one lucky 18" already makes this biased and lopsided towards the RN that it's simply silly. Yamato, a ship that was designed to fight multiple battleships at once could not have been defeated by Hood and PoW in an conventional engagement unless everything you listed happens. In short, everything goes wrong for Yamato and everything goes right for Hood and PoW.
paul.mercer
Senior Member
Posts: 1223
Joined: Fri Mar 26, 2010 10:25 pm

Re: Teleportation in time: Bismarck swap with IJN Yamato

Post by paul.mercer »

I would have thought that if Yamato was as heavily armoured as it was reputed to be - and given that the Japanese navy was pretty efficient and fanatical she would be unlikely to turn away from a battle and would not even need PE to back her up so would destroy Hood and PoW without too much trouble, even if she took a number of hits herself.
alecsandros
Senior Member
Posts: 4349
Joined: Wed Oct 14, 2009 2:33 pm
Location: Bucharest, Romania

Re: Teleportation in time: Bismarck swap with IJN Yamato

Post by alecsandros »

guest wrote: Fri Aug 26, 2016 7:17 am Yamato's fire control was not in any way shape, or form, bad, certainly no less accurate than other navies yet you seem to grant her much lower hit rates than that of the RN. In your simulation, the RN lands multiple crippling hits while Yamato lands all of 2 hits. This seems very lop sided and implausible. Yamato did not have a lower rate of fire than other battleships as commonly believed, she would have output a steady 9 rounds every 30 seconds for as long as she fired. While the British had more heavy guns and could statistically score more hits due to the 9 extra guns giving Yamato 2 hits and the British an upwards of 20 is simply absurd.
Yamato's main rangefinder had a baselength of 15meters and was amongst the most accurate, if not the most accurate, in teh world.

HOwever, that's irrelevant when 2 sets of torpedoes are coming hard towards her - and she needs to turn North to comb the tracks. It's a similar situation to that at Battle for Samar, when Yamato steamed away from the battle, to evade USN torpedoes. While turning away and steaming North, her accuracy would be irrelevant, as only the aft turret would train, while the smoke from the exhaust stack would be blown in the N-E direction (as historical), therefore obscuring her main rangefinder permanently.

On the other hand, the massive 270x38meters battleship would move on an exact linear course (as any deviation would entail the risk of getting hit by a torp - exactly as at Samar) - therefore the targetting of HOOD and PRINCE of WALES would be much easier.
RN ships straddling from 20km?
KGV straddled Bismarck in appalling weather from ~ 21-22km range. PoW doing the same against a 10% larger target is completely in line with capabilities of the time. Hood did not straddle Prinz Eugen, but "put her decks awash", and shell splinters landed on board the heavy cruiser. Distance to target was around 20-21km. If the target was Yamato (50% larger), hits may have been scored - again completely in line with capabilities of the time.
Then we have the 6 destroyers that are somehow able to close to 8km under fire from 8x8" from PE and 12x6" from Yamato. The idea of those 6 destroyers coming through unscathed is a bit far fetched. Acasta and Argent were heavily hit trying to close the range to Scharnhorst and Gneisenau and were later sunk by those same secondary batteries. That Yamato's secondaries in your simulation make zero impact on the outcome, that they are unable to score even a single hit is rather implausible.
During the battle of Samar, 3 DDs and 4 DDEs approached a Japanese battleline of enormous size (12 DDs, 6 cruisers, 4 battleships), and survived for over 1 hour , launching torps, firing their 5" guns, etc. DUring battle for Channel Dash, 6 destroyers approached at 3000meters from German battleline and launched their torps. Only 1 was hit (HMS Worcester), 6 times, by Gneisenau.
PoW closing to 16km? What is Yamato doing all this time? Sitting idly by and waiting to be sunk? So PoW somehow lands 2 hits from 16km while Yamato lands all of zero?
Combing torp tracks would last from 10 to 20minutes, until the torps consume their fuel - after that Yamato needs to steady back on another course, re-aquire target, etc. In that time, PoW/Hood do not have torpedoes to watch out for, and continue to fire against the enemy.
Torpedoes at 16-20km? British torpedo range was roughly 12km max, why would they be launching outside their max range? Did the British get Long Lances as well in this simulation? If Yamato is running away from the first torpedo attack at 16km, exactly how did the destroyers close to 8km to launch their second? What was PE doing and what were Yamato's secondary batteries doing? Sitting idle again?
Because calculations are done for the future. When Yamato charges to the South at 27kts, and the torps run to the North at 35kts, the combined approach speed is 62kts, so by the time the torpedo would have reached her max range (12-13km depending on type), the Yamato would be at ~10km from the initial launching point of the torps.
Historically, when Scharnhorst got torpedoed in 1940, by Ardent, the launching distance was probably around 13-14km, but Scharnrhost's course simply got her into the torpedo's track.
Yet somehow Yamato loses 2/3 of her main turrets to 14" & 15" fire? How?
Yes, WW2 turret damage was mostly shock damage, not penetrating damage. When Jean Bart got hit by Massachussets in Nov 1942, her only operational turret was jammed by the damage. Bismarck had at least 1 , if not 2 main turrets knocked out (but not destroyed) during her final battle - etc.

In any case, the destruction of the "soft systems" (rangefinders, directors) , by 14" and 15" gunfire, would make firing the turrets much more difficult, with greatly reduced efficiency.
On the other hand, how does the 18" hit from Yamato on PoW's forward turret not destroy the ship? There is an awful lot of combustible material inside a turret and the 18" shell would not have simply detonated inside the turret, the penetrating power of that shell would have drove it into a magazine before exploding - with obviously disastrous results.
RN ships were built with safety in mind, and the explosion inside the turret would have been contained. The main magazines of the KGV class were positioned deep inside the ship, close to the double bottom, and would not have been affected.

PoW's turret and barbette armor would have been unable to stop even a 15" hit from Bismarck, never mind an 18" hit from Yamato!

In short, everything goes wrong for Yamato and everything goes right for Hood and PoW.
The tactical disposition gives RN the edge. With Yamato coming from North to South, while under continous surveillance by Norfolk/Suffolk, it's almost impossible for the Germans to win. Holland would position himself to close the T, having 18 x main guns to fire against 6 x main guns to fire (as Yamato would initialy move South, having her aft turret masked). It woudl be the reverse of the historical battle for Denmark Strait, where Bismarck with 8 x main guns responded fire against only 10 x main guns ( 6 on PoW + 4 on Hood), because the other 8 main guns of the British force were masked.

Adding the 6 destroyers, the chances of correctly aiming/aquiring the target for the German force drop very much, as they woudl be required to manouvre to avoid torps (and in doing so, keeping a fixed course - easily trackable and fired upon).
Post Reply