Bismarck Disappears

[Carl Schwamberger]

... or any of the other German capital ships.

Assume the HMS submarine Terribleluck comes to the edge of a rain squall & finds the Bismarck coming on to a good fringe angle, at very close range. Close enough the torpedos have just enough time to arm. The skipper manages to get them off, but decides to dive as he turns the sub away. The tight spread hits close together creating massive damage. The crew is unable to establish water tight conditions and the turn away the captain ordered only causes water pressure to collapse damaged bulkheads. In seconds the ship is listing & then a series of internal explosions breaks it into, both halves capsizing & going under in minutes. Think Barham. No radio signal gets off, the few crew in the water die of hypothermia in a couple hours or less. The wind disperses the thin debris field.

Unfortunately for the Brit crew they are too close in their diving turn away and the compression wave causes breakage & catastrophic damage. In a few minutes the sub falls well below its rush depth. Feel free to apply this scenario to other capitol ships.

So, my primary question here is how long does it take history to figure out what happened to the Bismarck? Assume no evidence from a current radar contact from lurking RN cruisers or eyeballs from a passing Catalinia.

[maltesefalcon]

In the case of Bismarck it would depend on where/when you diverted from the OTL. The vessel was under surveillance by air and radar for much of its maiden and final voyage. So the search could begin where they lost contact, which would narrow the search field somewhat.
Not to mention if the RN were unaware of the vessel's sinking they would keep looking for some time in order to attack it.

[T. A. Gardner]

Would Prinz Eugen be with her? What would be the time between sinking and last position report to somewhere? What is the depth of water where Bismarck sank?

[Carl Schwamberger]

Would Prinz Eugen be with her? What would be the time between sinking and last position report to somewhere? What is the depth of water where Bismarck sank?

It would have to be after the pair seperated. The Prinz Eugen took a different route to Brest. When they separated there was a sort of tricky dance move they did that confused the radar operators on the Norfolk or Suffolk and slipped the PE over the horizon. After that the Brit radar operators had increasing difficulties in keeping contact until the Bismarck was able to evade the radar entirely. There was roughly a day where there was no contact/location other than a radio DF when Lutjens sent a message to KM HQ. After a patrol plane made a sighting cruisers were able to intercept and follow with their radar again.

...Not to mention if the RN were unaware of the vessel's sinking they would keep looking for some time in order to attack it.

Could be as much as a week before the RN accept the Bismarck was gone. They were getting relevant messages from Bletchley Park, but not all were intercepted, time from intercept to decryption was variable. The KM had the best trained operators and procedures, the luftwaffe had the worst. Often it was relevant information in Luftwaffee radio messages that gave the first clues about KM activity & which KM messages to focus the decrypt efforts on. Eventually the Brits would read enough messages of the Germans to understand they had lost their prize ship.

Im not clear of the state of British and German underwater acoustics in 1941. A detonation that size might be audible for some distance. Would the operators on the Brit or German boats notice & log in the noise, and would they be able to record a useful bearing? Even with todays equipment acoustic bearings are distorted by density gradients in the water that create barriers, channels, and reflective structures underwater. If enough ships record even a rough bearing then a search of their log books could narrow down the search area to a few thousand square kilometers. If not then the best any one could do is a area of tens of thousands km2 between Ireland and Greenland.

[T. A. Gardner]

So, I would say Bismarck is rediscovered in the 80's at some point. This is when sonar technology had advanced far enough to do bottom scans that were sufficiently accurate that a wreck could be found. You couple that with the necessary algorithms and computer power then available to determine a likely search area in the way the USS Scorpion of the K-129 (partially raised by the Glomar Explorer) were found.

With a rough location determined, a ship using a towed array scans the area and finds the wreck.

[PunctuationHorror]

It took Rob Ballard quite a time in the 1980s to find the Titanic and the Bismarck. And he had the coordinates of the sinking location of Titanic and Bismarck. Think of the two lost subs USS Scorpion and USS Thresher (Ballard visited them to get his Titanic trip funded, so they came into my mind). Their last course was known, there were reported positions and still it took some time to llocate them.

Let's say the contact to Bismarck is lost for one day and she sails with 20knots - that's 480 nautical miles. Theoretically, she can go in any direction, so she can be anywhere on the area of a circle with a radius of 480nmi around her last known position. 480nmi are 550mi are 889km. This makes an area of pi*(480nm)² = pi*230400nmi² = 723823 square nautical miles, or 550mi * 550mi * pi = 950332 sq mi. An area three and a half times the size of Texas.

Good luck scanning all this.

[maltesefalcon]

The sinking and breakup of any vessel that size would certainly create a huge oil slick, which can be spotted from the air if weather and light conditions are good. Patrol planes could follow the slick and if no vessel was seen, they would eventually draw the correct conclusion.

Especially with Ultra intercepts as per above. The precise location would not be critical in wartime and it was risky to even search for survivors if there was a chance of U-Boats skulking about.

As it was, IRL it took a lot of effort to locate the ship, even when eyewitnesses saw it go down in a known location.

[Carl Schwamberger]

The Germans are going to suspect some British secret weapons, or technique for a existing weapon. The idea a BB could sink in minutes from a few torpedo hits, with no radio signals or survivors was not what people would accept in 1941. Later the Barham did exactly that & there was a lot of shock over it.

The Brit Deception Committee was not yet really functional, so theres no real institution that can take immediate advantage of the German fears. Still some clever Brit Sea Lords can read the tea leaves in the Bletchley Park decrypts & over the next months or year hints can be dropped, in the press, via the Double Cross system, in foreign capitols where German diplomats still lurk. Hints that RN uber weapons and skill toasted the Bismarck in seconds...

[T. A. Gardner]

It took Rob Ballard quite a time in the 1980s to find the Titanic and the Bismarck. And he had the coordinates of the sinking location of Titanic and Bismarck. Think of the two lost subs USS Scorpion and USS Thresher (Ballard visited them to get his Titanic trip funded, so they came into my mind). Their last course was known, there were reported positions and still it took some time to llocate them.

Let's say the contact to Bismarck is lost for one day and she sails with 20knots - that's 480 nautical miles. Theoretically, she can go in any direction, so she can be anywhere on the area of a circle with a radius of 480nmi around her last known position. 480nmi are 550mi are 889km. This makes an area of pi*(480nm)² = pi*230400nmi² = 723823 square nautical miles, or 550mi * 550mi * pi = 950332 sq mi. An area three and a half times the size of Texas.

Good luck scanning all this.

If the Bismarck could make 20 knots after being damaged, then it wasn't going down at all. To sink the ship, the torpedo defense system would have to have been penetrated and progressive flooding taken out the boilers and or engines leaving the ship without power to fight the damage.

For example, the USS California at Pearl Harbor took three torpedoes. Had the ship taken that damage in full battle readiness with the full crew aboard it wouldn't have sunk at all. USS W. Virginia took 7 or 8 torpedoes and sank in good part because the torpedo defense system was overwhelmed. In the case of Prince of Wales, it was a stroke of luck that the early Japanese torpedo hits took out one shaft resulting in heavy flooding in numerous compartments, then in the engine rooms leaving the ship nearly DIW almost right from the start.

The USS Scropion's or Russian sub K-129's positions are more analogous to what you are claiming and both were found, so it is possible by the 80's to do that.

[Carl Schwamberger]

...
If the Bismarck could make 20 knots after being damaged, then it wasn't going down at all. To sink the ship, the torpedo defense system would have to have been penetrated and progressive flooding taken out the boilers and or engines leaving the ship without power to fight the damage.

Thats one of the reasons I had the submarine launch from minimum range, so two hits relatively close together be plausible. There is also the question of cumlmative damage from the PoW hits and the hit from the Victorious torpedo plane. The damage was such the Bismarck slowed to 16 knows for several hours to reduce stress 7 twisting on the damaged frame sections. I'm unsure what repairs were done to enable 20 knots again.

[Takao]

Problem...Much of the blast vents up, not down. Minimal Shockwave. U-331 was not sunk from Barham's detonation, despite being in a situation duplicating your proposed scenario.

[TheMarcksPlan]

Bismarck found in ~2100 when AI drones mapping the entirety of the ocean floor stumble across it and MH370.

[T. A. Gardner]

Bismarck found in ~2100 when AI drones mapping the entirety of the ocean floor stumble across it and MH370.

Right next to each other near Antartica and the Nazi secret U-boat base...

[Sheldrake]

I know the answer to this .

In the absence of any confirmed information about the loss of the Bismarck it becomes part of the nexus of WW2 conspiracy theories with Hitler joining the crew in 1945 with Elvis as the on board entertainment sailing the sea of Tranquility - according to the Daily Star.

[T. A. Gardner]

I know the answer to this .

In the absence of any confirmed information about the loss of the Bismarck it becomes part of the nexus of WW2 conspiracy theories with Hitler joining the crew in 1945 with Elvis as the on board entertainment sailing the sea of Tranquility - according to the Daily Star.

I heard the ship survived, made it to that secret U-boat base where it was used to construct a steam powered starship that met up with the Yamato to defeat alien invaders...



See! It's gotta be real!