The Sikorsky SH-3 Sea King

By Patrick J. Walsh

Searching the sky for some sign of the Sikorsky SH-3 Sea King — their helicopter — the crew of the USS Altair (AKS-32) waited eagerly. Then, they heard it, the sound of the rotors cutting the air, as the distinctive helicopter with the orange nose neared the flight deck on the ship’s fantail.

As an underway replenishment stores ship responsible for supplying the U.S. Sixth Fleet in the Mediterranean, the Altair typically delivered some 800 tons of supplies a month to ships at sea. At that moment in spring 1962, however, the Altair became the first Service Force ship of the U.S. Navy to deliver 1 million pounds of cargo via vertical replenishment — that is, by helicopter.


Cold War Hero

In those pioneering days, there was a novelty to every aspect of the process of using a helicopter to supply ships at sea. In the case of the Altair, the ship’s helicopter flight deck had only been added in 1959. And its brand-new SH-3 Sea King, which came equipped for anti-submarine warfare (ASW), was adapted for such deliveries.

The innovative SH-3 was the first helicopter in the U.S. arsenal to be designed to serve as both a “hunter” and “killer” of enemy submarines. (Before this model, these tasks were assigned to separate aircraft.) Its state-of-the-art ASW equipment included dipping sonar and sonobuoys that enabled its specially trained crew members to locate Soviet submarines and track their movements. It was also equipped with various armaments capable of destroying enemy submarines in combat conditions.

As a result, the Sea King was a key Cold War asset for the U.S. Navy from the moment of its introduction in September 1961. The versatile rotorcraft also quickly proved well-suited for the Navy’s initial experiments in vertical replenishment.


Expanding Replenishment Options

Conventional “UNREP,” as underway replenishment is commonly described in military terms, involves the ship-to-ship transfer of all the materials necessary to support the mission and crew of a ship at sea. From the moment the two ships raise the “Romeo flag,” indicating their readiness to begin the process, this direct transfer requires careful adherence to a well-established set of procedures designed to ensure safety and efficiency.

Both ships must maintain a constant speed and position while the rigging used to move pallets of supplies is physically linked from one ship to the other. At the end of the process, similar procedures govern the process of disconnecting the rigging and separating the delivery ship and receiving ship.

The introduction of the helicopter delivery option — or “VERTREP,” for vertical replenishment — broadened the logistical capabilities of supply ships by enabling the direct transfer of supplies from ship to ship or between ship and shore. Whether used in conjunction with traditional UNREP procedures or on its own, vertical replenishment soon became a common method of delivering ammunition, food, supplies, spare parts, and personnel to ships at sea.


Enter the Sea Knight

The U.S. Navy’s early VERTREP experiments utilized the SH-3 aboard the Altair and the fleet oiler USS Mississinewa (AO-144) in 1962 and 1963. Once those deployments proved the concept sound, the process was formalized with the use of a Boeing Vertol UH-46 Sea Knight aboard the USS Sacramento, beginning in November 1964.

The U.S. Navy’s UH-46 was a modified version of the CH-46, the U.S. Marine Corps helicopter that saw heavy use in a variety of missions throughout much of America’s involvement in the Vietnam War. By the late 1960s, the UH-46 had become the primary helicopter associated with the vertical replenishment role. (The SH-3 and other rotorcraft were still used for the task in situations where a Sea Knight was not readily available.)

Other Uses and Models

In addition to its pioneering roles in the development of vertical replenishment and anti-submarine warfare, the SH-3 Sea King also was used for combat search and rescue during the Vietnam War. This workhorse also served to retrieve manned space capsules during the National Air and Space Administration’s (NASA’s) Mercury, Gemini, and Apollo space programs.

Ultimately, both the Sea Knight and the Sea King were replaced by versions of the Sikorsky Seahawk. The Sea Knight gave way to the MH-60 Seahawk in 2004, and the Sea King was replaced by the SH-60 Seahawk in 2006.

Image Credits:

Image #1 - The versatile Sikorsky SH-3 Sea King was the first U.S. helicopter capable of performing the entire spectrum of anti-submarine warfare (ASW) tasks, from detecting and tracking enemy submarines to destroying them. In this photo, a Sea King takes off from the USS Peterson in June 1988. (Image courtesy of the U.S. National Archives and Records Administration)

Image #2- From its first use for the task in November 1964, the UH-46 Sea Knight was closely identified with the development of vertical replenishment procedures. In this 1988 photo, two Sea Knights transfer cargo between the ammunition ship USS Nitro and the aircraft carrier USS Independence. (Image courtesy of the U.S. National Archives and Records Administration)

Image #3 - An SH-3 Sea King helicopter carries out a vertical replenishment flight in the Pacific in December 1979, transferring supplies from the oiler USS Passumpsic to the aircraft carrier USS Midway. (Image courtesy of the U.S. National Archives and Records Administration)

Image #4 - The flexibility of vertical replenishment makes it a particularly good option for the delivery of high priority items to ships at sea. Here, a UH-46 Sea Knight delivers mail to a ship during Operation Desert Shield in 1990. (Image courtesy of the U.S. National Archives and Records Administration)