Just had my first ever submarine experience. How did they communicate with the world?

[CaptBones]

Uhhmmmm…folks…it seems to me that we’re mixing a lot of apples and oranges, adding a few pomegranates and then throwing in an avocado or two for good measure.

First, it would be helpful to remember that there are huge differences in the technologies, strategic employment and tactical operations of WWII submersibles and Cold War submarines. There are also significant differences between today’s submarines and those in service during most of the Cold War.

Second, we should also keep in mind that the WWII German and US submarine forces were very different in many of the ways they operated, but similar too. Not to mention that there are even greater differences between the operational doctrines of today and during the Cold War, and those of any/all WWII submarine services.

So…perhaps we should be clear about the era we’re writing about with each comment we’re writing. Let’s start with this:

Q: “…but do you have an example of how they tactically rose to the surface without being detected by nearby enemies?

A: Which “they” are you referring to? Considering submarines in WWII, “they” didn’t. In general, you wouldn’t surface close to the enemy unless you’re; a) critically damaged and intend to surrender (or fight it out and die valiantly) or; b) “the enemy” is a lone unarmed merchant vessel you’re going to engage with deck gun or; c) it’s the middle of the night and you’re going to engage on the surface.

Q: Say the submarine needed a status update before committing to strike, how would they go about getting this information?

A: That doesn’t really fit in with WWII submarine warfare; what kind of “status update” are you thinking would be needed? To quote Dudley W. Morton; “Find ‘em, chase ‘em, sink ‘em.” Despite the differences in operational methods, the German and American submariners both essentially followed that doctrine. The biggest difference was in the German “Wolfpack” method of operation. There, the gathering and concentration of units to attack a convoy was coordinated and controlled by the HQ Command ashore and that did depend on a steady stream of 2-way communication between the individual U-Boats and BdU. Unless detected by the enemy, the boats would travel to the designated intercept position on the surface and would get updated reports on the convoy and orders from HQ by Enigma-encrypted radio messages (good scenes of that in “Das Boot”). That turned out to be an Achilles heal though; radio direction finding equipment was finally installed aboard ships and aircraft as well as ashore and the ability of the Allies to detect and localize U-Boat transmissions was one of the factors in defeating the wolfpacks.

Q: Also, what type of decryption methods were used by the enemies?

A: That is a story in itself. Google “Enigma” and see what comes up; by all means see the movie “The Imitation Game”. About the only redeeming quality in the movie “U-571” (don’t have a hissy-fit Sailor Steve;>) is the dedication, in the closing credits, concerning the capture of Enigma materials during the war.

Q: In the heat of the moment, where it was paramount not to be detected, would submarines have to carry out orders that were already set when departing on the mission? I.e., no turning back once things got heated?

A: Yes, but with due consideration for the command and control procedures inherent in the “Wolfpack” tactics. Not to put too fine a point on it, but the mission orders were generally very broad…“Proceed to ‘such and such’ a position/area and then “Find ‘em, chase ‘em, sink ‘em.” Of course, there were a lot of special missions as well and those orders would be more detailed.

Q: Why would a submarine be forced or required to transmit?

A: With respect to WWII German U-Boats, that goes back to the “Wolfpack” tactic and the need to communicate between the boats and the HQ ashore. USN subs in the Pacific had much fewer requirements to do so. They did not report their arrival in a patrol area or their positions...unless directed to do so by their Op Orders or by message. But, they were required to report when enroute back to port from patrol and they also needed to copy the “Fox” Broadcast for revisions to orders, contact reports and general information of use to carry out their mission orders.

If you want a lot of accurate and factual information, there are a plenty of good books on these subjects (and a few not-so-good). There are also a couple of threads right here on SubSim that concern the real world of WWII submarine warfare in the Atlantic and the Pacific. Have fun getting “submerged” in all of it.

[Oberon]

B515 is a Tango diesel electric submarine, so she would be rather quiet, if I recall probably one of the quietest diesel boats the Soviets had until the Kilos.
So...communication. IIRC generally speaking orders would be sent at specific times during the day during which time the submarine would either put up a mast if the coast was clear, or stream a wire if it wasn't. A small line of wire is not that easy to pick up on radar and unless you're pretty much on top of it it's also harder to see than a mast which leaves a trail.
That being said, in certain waters, such as the Pacific, if you're that close to the surface then a passing helicopter might actually be able to see the submarine in the clear water, not exactly ideal, so if a helicopter was detected by the submarine then chances are it would just avoid being near the surface wherever possible or spend as little time up there as possible.

Let's also bear in mind detection, radar is generally done through a series of sweeps and radar returns can be made off all kinds of rubbish in the sea, so if a submarine sticks up a scope and a ship gets no more than two returns off it, the radar operator may classify the returns as ocean clutter, which is when the radar reflects off something random on the sea, like a flock of birds or something. So a quick sub commander can get a mast up, do a sweep and slam it back down again before the surface radar operator gets a solid lock and determines that it's a mast out there. That's one of the reasons that submarines like the Astute and Virginia classes have periscopes that are essentially a load of video cameras around a pole, you can pop it up, grab the footage you need, drop it down again and then analyse the footage you've got without having to leave the mast up or suffering motion blur as you turn the scope around quickly.

There is another method, and that's ELF (Extremely Low Frequency), and this is mainly used for missile submarines in order to tell them to come up to periscope or wire streaming depth in order to receive a more detailed message, since ELF has a very slow transmission time and as such is really only suited for short messages. If you've seen the film 'Crimson Tide', you'll see that they get an ELF message to bring them up to communications depth in order to receive missile targetting instructions.

And, of course, there's the underwater telephone for communication between submarines. IIRC the nickname for it is the Gertrude and it's pretty primative and often a bit like trying to have a conservation on a very bad phone line, but it does work.

In the future, there's a lot of talk about laser based communications, a bit like fiber optics but through the water rather than a fibre tube. The precise physics of it are a bit beyond me, but I do know that laser comms on submarines is something that has been mulled over for a while now and it wouldn't surprise me if it is in actual service but on a classified trial basis.

I hope that makes sense...and that any sub experts can correct me where I've gone wrong, I'm certainly no expert but I have read a bit over the years, especially around Cold War submarines (my favourite era) and so I've picked up the odd thing here and there. There's some articles I'll link as well for some extra reading:

https://en.wikipedia.org/wiki/Commun...ith_submarines

https://en.wikipedia.org/wiki/Underwater_telephone

http://www.sea-technology.com/featur...munication.php

http://www.naval-technology.com/feat...quantum-level/

[Osmium Steele]

Originally Posted by Oberon

And, of course, there's the underwater telephone for communication between submarines. IIRC the nickname for it is the Gertrude and it's pretty primative and often a bit like trying to have a conservation on a very bad phone line, but it does work.

It sounds very much like two cans on a piece of piano wire.

[CaptBones]

Yeah...but without the wire!

[Dallsim]

So many thorough replies so it will take a while to respond to all. I will start by replying and asking more questions to CaptBones and l02turner because I just happened to see “Das Boot” on Blu-ray with the girlfriend this weekend. What a phenomenal film!

Originally Posted by CaptBones

The biggest difference was in the German “Wolfpack” method of operation. There, the gathering and concentration of units to attack a convoy was coordinated and controlled by the HQ Command ashore and that did depend on a steady stream of 2-way communication between the individual U-Boats and BdU. Unless detected by the enemy, the boats would travel to the designated intercept position on the surface and would get updated reports on the convoy and orders from HQ by Enigma-encrypted radio messages (good scenes of that in “Das Boot”). That turned out to be an Achilles heal though; radio direction finding equipment was finally installed aboard ships and aircraft as well as ashore and the ability of the Allies to detect and localize U-Boat transmissions was one of the factors in defeating the wolfpacks.

Originally Posted by CaptBones

A: That is a story in itself. Google “Enigma” and see what comes up; by all means see the movie “The Imitation Game”.

Originally Posted by l02turner

Ya'll probably know this but the Germans had a weakness when it came to communications - the allies broke the code pretty early and I believe it was Sub overall commander Doneitz who required all subs to report their position on a daily basis

At the very beginning of the film, it was stated that, despite Hitler clearly knowing that the German naval fleet had no chance in surviving against the Allies, he kept sending the submarines into their deaths. The Captain questioned numerous times how the Allies were miraculously able to “anticipate” the whereabouts and attacks of the German submarines. The story takes place in 1941 and I assume Enigma was cracked without the Germans being aware?

If I remember “The Imitation Game” correctly, the Allies purposely sacrificed some of their own convoys in order to not raise too high a suspicion that Enigma had been decrypted. In Das Boot, when the submarine manages to take out two ships while firing at four, they lose track of the Destroyer’s position, leading to the submarine being taken by a surprise attack from another direction. Would you believe this to be a calculated sacrifice, or some form of misdirection by the Allies in order to lure the submarine into a vulnerable position?

Originally Posted by Oberon

In the future, there's a lot of talk about laser based communications, a bit like fiber optics but through the water rather than a fibre tube.

After checking the link provided by Oberon, I became intrigued to read more about Laser Communication and learnt of a new term called “Quantum Key Distribution” (QKD), a new method for secure communication. This technology behaves based on quantum mechanics and takes advantage of light, or laser light to be more specific. Apparently, QKD produces a shared secret key, which is randomly made, to two parties who will use it to encrypt and decrypt the messages they send and receive. If somebody were to eavesdrop or try to read the key, the attributes of the key will be altered and you would instantly know that the key has been tampered with. I.e., once read, it’s known. The key would be discarded and a new would be sent and only used if it remains untouched.

Imagine if the Germans had a similar type of device back then? I assume submarines nowadays are looking to take advantage of laser communication so that they can stay deep under water and remain undetected while still being able to communicate with the world above sea level?

The topic of Enigma QKD actually got my thinking about which similar security measures are in place today in order to make sure our daily conversations stay private. After some digging, I discovered that there are methods to encrypt communication such as emails with something known as SSL (Secure Sockets Layer) and TLS (Transport Layer Security). There was this one site which features a few guides giving a great introduction to how you can send emails securely:
https://www.1and1.co.uk/digitalguide...tion-with-ssl/

Not sure how comparable it is to Enigma, but digital guide explains that, when we send emails without encrypting them, they are sent as plain text and can be easily intercepted and read while underway to the proper recipient. By sending emails using TLS or SSL, the email will be encrypted and cannot be deciphered by “third parties” due to the fact that they do not have access to the key that is needed to decrypt the message.

It also looks as though many email clients seem to offer this encryption feature in the settings, which you can turn on and off yourself. When I think of it, I am not sure if I have enabled mine yet but will have an immediate look right after posting . Another bonus listed for the use of SSL and TLS seem to be with securing data transmission on websites if important and private information is shared.

I hope the future makes use of Quantum Key Distribution. The great advantage I find with it is the ability to identify any eavesdropping or tampering of the key. I wonder if submarines will be the first to incorporate this technology, while the public still has to wait quite a while before it becomes the norm

Anyhow, will get back to other people’s post later. Too much to ask!

[CaptBones]

Q. The story takes place in 1941 and I assume Enigma was cracked without the Germans being aware?

A. Yes. Take a look at uboat.net, under the "Technolgies" tab, for a thorough explanation.

Q. Would you believe this to be a calculated sacrifice, or some form of misdirection by the Allies in order to lure the submarine into a vulnerable position?

A. Neither. It's a filmmaker's presentation of an attack on a convoy...very accurate (Heinrich Lehmann-Willenbrock was a technical advisor), but still a theatrical version of a submarine attack on a convoy. Give it a try yourself in Silent Hunter 3...start with the stock version, then try some MODs like Living Silent Hunter 3 and/or GWX3. Good luck.

[Dallsim]

Some great information on uboat.net. The ultimate site for German submarine info A lot to digest.

Back to the film, I cannot forget the scene when the submarine goes under after losing control, sinking towards the maximum threshold before collapsing. I now read on Wikipedia that the "crush depth" for the U-96 at the time was somewhere between 250 and 295 meters. While watching, I had no idea how many meters could be sustained, and I wonder if the crew knew of any specific crushing treshold as well. My heart was pumping, to say the least! Was this type of information transparent? In the Film, they test the submarine at the beginning. Is this normal behaviour or once more made for dramatical effects?

Exciting to read that they are making a TV serie sequel to Das Boot, which will be released in 2018. 8 episodes lasting an hour each. Now that they cannot rely on Heinrich Lehmann-Willenbrock for authenticity, who will they turn to in order to ensure that submarine experts like yourselves won't have a "hissy-fit" when watching