PT 27

The most exciting part of our deployments was participation in actual antisubmarine warfare against real USSR submarines. From time to time high command decidered to crack up the heat on the Soviets and conduct round the clock surveilance against Soviet assets. Usually this meant flying back to back missions with minimum crew rest, which if memory serves was 13 hours. This meant that at least this much time had to past between completion of the previous flight's debrief and the secheduled start of the next mission's briefing. Depending on transit time to the operating area, this could result in a cycle of 20-30 hours. During this operation the cycle was about 28 hours, which wreaked havoc with our circadian rhythms.

An interesting operation was conducted against PT27, a Soviet Type 2 nuclear submarine, Echo-II class (see USN Photo nearby). The submarine was enroute from its operations area (presumably in the Indian Ocean) to its host port on the Soviet Pacific Coast (possibly Vladivostok). Its track took it through the South China Sea then the Taiwan Straits. Therein was the difficulty.

Expanded view of ocean depth in the Taiwan Straits. White shading indicates depths of 500 feet or less. Maxium depths in the area are several thousand feet.

We were tasked to maintain continuous acoustic contact with the Echo-II. Under most acoustic conditions, this is straightforward for a noisy sub like the Echo-II. Directional sonobuoys can be used the high signal lvel to maintain a fix on the submarine's location. This works well if the acoustic conditions are such that the sound travels in a direct path from target to sensor. This is not always the case. For example, if the ocean is sufficiently deep that sound emitted can be refracted by the cold deep water such that a region of high acoustic signal occurs ten of miles from the submarine because the sound rays bend upwards.

Conditions in the Taiwan Straits were not amenable to direct path contact. Relatively shallow water, combined with rocky sea mounts (see maps) meant that sound radiated from a submarine would reflect from these surfaces and appear to come from another direction to our direction-finding sonobuoys. So a principal tool for tracking was unavailable.

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