Operation Nimbus Stream was the 1975 (July-Oct) clearance of naval mines off the Egyptian cities of Port Said and Damietta. On board USS Inchon (LPH-12), US Navy Helicopter Mine Countermeasures Squadron HM-12, flying Sikorsky CH-53 Sea Stallion helicopters and towing MK-105 hydrofoil sleds, performed the mine sweeping operation. A detachment from Marine Medium Helicopter Squadron HMM-261, flying Boeing Vertol CH-46 Sea Knight, helicopters provided airborne search and rescue stand-by support. The main body of HMM-261 had been off-loaded at Sigonella, Sicily prior to departure for Egypt.