Operation MARHUK: The Combat Debut of the Marine's AH-1J SeaCobra

Marine SeaCobras took a beating operating at sea

The first US Marine Corps AH-1 Cobra gunships in action were actually AH-1Gs which were ordered by the Marines in 1967- having closely watched the Army development of the Cobra gunship, 72 helicopters were requested for one helicopter attack squadron in each of its three Marine Air Wings. Despite having the approval of the Secretary of the Navy, Defense Secretary McNamara overruled the decision and only allowed the Marines to order 38 of the single-engined AH-1G variant. With the first Marine AH-1Gs going into action in Vietnam in April 1969, reports from the field couldn't have been more salutatory in the effectiveness of the Cobra gunship. Based on that initial experience, the Marines wanted a more powerful Cobra- one with twin engines, Marine avionics, a rotor brake for shipboard operations and a harder-hitting gun in the undernose turret. After overcoming the resistance of an obstinate Secretary McNamara, the AH-1J SeaCobra went into production with the first examples undergoing combat evaluation in South Vietnam in February 1971. With the onset of the Easter invasion by North Vietnam of the south and the American response, Operation Linebacker, the first Marine helicopter attack squadron, HMA-369 based in Okinawa, was called upon shortly after its establishment to conduct offensive operations against North Vietnam. 

The USMC had the AH-1J built from the start to operate from ships

At the time, Army Cobra gunship were operating in South Vietnam against the invasion thrusts of the North Vietnamese Army. Despite having just received its new AH-1J SeaCobras, Admiral John McCain, Jr, head of the US Pacific Command, wanted to make sure that the blockade of North Vietnam was complete. Even though carrier aircraft had sown mines closing Haiphong Harbor, the North's main port, the North Vietnamese had resorted to having Chinese and Soviet cargo ships anchor offshore various locations and cargo would be offloaded into smaller sampans for transfer to the shore. This way the mined sea lanes could be avoided. Because fixed wing carrier aircraft were urgently needed for Operation Linebacker attacks on North Vietnam, it was decided that the AH-1J SeaCobra would be ideal for the role of maritime interdiction off the coast of North Vietnam. In the entire Pacific theatre, only HMA-369 in Okinawa had suitable helicopters for the job and Operation MARHUK (Marine Hunter-Killer) was born. It would be the Bell AH-1J SeaCobra's baptism of fire and off the coast of the heavily defended North Vietnamese coast, no less. 

HMA-369's "Marhuker" patch

 HMA-369 originally wanted a helicopter carrier to be based on for Operation MARHUK, but the Navy's LPHs were heavily committed else where and the 18 officers, 99 men and seven AH-1J SeaCobras of HMA-369 that were ready to deploy in June 1972 were shoehorned into the amphibious transport ship USS Denver (LPD-9). Marine brass give the squadron officers a blank check to do what ever was necessary to get HMA-369 to the war zone and the nickname "Marhukers" was given to the officers who improvised and bent and possibly broke many rules to make their SeaCobras combat ready. Even 5-inch Zuni rockets were procured, a weapon that had not yet been cleared for use from the AH-1J. The ship and its escorts would be positioned near the Hong La anchorage further south down the coast from Haiphong. Here Chinese and Soviet merchant ships anchored offshore and North Vietnamese sampans offloaded cargo offshore to bring into Hong La. Since the rules of engagement forbade hitting the merchant ships, the SeaCobras stayed at least 500 yards away from the ships and remained overwater the whole time as the North Vietnamese had heavy AAA guns on  the shoreline. The SeaCobras operated in pairs and would sink the sampans with their Zuni rockets and 20mm undernose cannon. The pilots were also trained to call in naval gunfire and air strikes while the gunners in front seats of the AH-1Js focused on the sampans. After several weeks, the shore-based heavy AAA guns learned not to fire on the SeaCobras thanks to the naval fire support and air strikes the pilots would call in. 

In August 1972 HMA-369 moved to the USS Cleveland (LPD 7) and then again to the USS Dubuque (LPD 8). Over the course of Operation MARHUK, the AH-1J SeaCobras were called on to provide air cover for downed aviators in the North as well as functioning as forward air controllers for Navy strike aircraft. Missions ranged from 80 miles north of the DMZ to as far north as 80 miles south of Hanoi inland! When Operation MARHUK ended on 26 January 1973 with the end of Operation Linebacker II, nearly 1,000 sorties had been flown with 123 sampans sunk, further straining the logistics of North Vietnam that eventually drove them to the bargaining table. It was quite a stunning debut for the AH-1J SeaCobra. 

Source: Helicopter Gunships: Deadly Combat Weapon Systems by Wayne Mutza. Specialty Press, 2010, p72-76.