Very low frequency and extremely low frequency transmissions can penetrate seawater, but submerged boats cannot carry antennas large enough to transmit in return. VLF can reach tens of metres and ELF hundreds, with both limited to short one-way instructions. These systems suit simple messages to strategic deterrent forces, but they cannot provide detailed tactical coordination for a fast-moving hunt. A submarine needing fuller information must approach periscope depth for satellite or other communications, increasing its exposure to aircraft and surface sensors.
Chapter · 53:03-55:56
Why submerged communications constrain coordination
Learn why VLF and ELF can reach submerged boats but cannot support the detailed dialogue needed for a fast-moving hunt.