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

[CaptBones]

VLF wasn't in use during WWII or for much of the Cold War. VLF messages are very short coded signals; not quite like Fleet Broadcast message traffic and definitely not for 2-way communication.

Getting and sending messages over long distances in WWII and during much of the Cold War was done primarily with HF, using wire or whip antennas....had to be on the surface to send but could receive with wire antennas at shallow submergence. I once established and maintained a two-way "full period termination" teletype link with NAVCOMMSTA Pearl Harbor (Wahiawa) from the North Pacific "Broad Ocean Area", over 2,500nm, with a 55W...55 Watt, not kilowatt...transmitter. Ham radio operators do that, and better, all the time.

Later during the Cold War and today, UHF, VHF and EHF satellite uplink/downlink became the primary methods of two-way communication, which requires putting an antenna on or above the surface. HF Broadcast is still available and can still be received at shallow depths with towed wire antennas. Keep in mind, submarines are the "Silent Service"...they do not transmit unless compelled or required to do so.

[Dallsim]

Originally Posted by CaptBones

Getting and sending messages over long distances in WWII and during much of the Cold War was done primarily with HF, using wire or whip antennas....had to be on the surface to send but could receive with wire antennas at shallow submergence.

Perhaps this will be shown in Das Boot, Red October or some of the other films you suggested, but do you have an example of how they tactically rose to the surface without being detected by nearby enemies? Say the submarine needed a status update before committing to strike, how would they go about getting this information? Also, what type of decryption methods were used by the enemies? 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?

Originally Posted by CaptBones

Keep in mind, submarines are the "Silent Service"...they do not transmit unless compelled or required to do so.

Why would a submarine be forced or required to transmit? The U-434 or B-515 could stay submerged up to 3 1/2 days. Would it be to get "sick" crew off the submarine or to report on important findings? How many percent of crew on "injury reserve" could a submarine afford?