Singapore Navy and US Navy have conducted sea operations in South China Sea.

The Republic of Singapore Navy Formidable-class frigate RSS Supreme (73) steams alongside the U.S. Navy Lewis and Clark-class dry cargo and ammunition ship USNS Carl Brashear (T-AKE 7) during a replenishment-at-sea. The U.S. Navy routinely conducts cooperative operations with partner nations throughout the Indo-Pacific region.
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The Republic of Singapore Navy Formidable-class frigate RSS Supreme (73) steams alongside the U.S. Navy Lewis and Clark-class dry cargo and ammunition ship USNS Carl Brashear (T-AKE 7) during a replenishment-at-sea. (Picture source U.S. Navy)

The Formidable-class multi-role stealth frigates are the latest surface platforms to enter into service with the Republic of Singapore Navy, and are multi-mission derivatives of the French Navy's La Fayette-class frigate. 

The Formidable class have a significantly reduced profile than the La Fayette class and its other derivatives,[8] due to the smaller superstructure and the use of enclosed sensor mast technology.[9] The frigate is also constructed entirely of steel, unlike the La Fayette class which makes extensive use of weight-saving composite structures in its aft superstructure block.

The frigates are equipped with Boeing Harpoon missiles and Oto Melara 76 mm guns for surface defence. The Harpoon missile has a range of 130 km and uses active radar guidance. It is armed with a 227 kg (500 lb) warhead. There is space for as many as 24 Harpoon missiles at the center of the ship. The gun fires 6 kg shells to a maximum range of 30 km at a firing rate of up to 120 rounds per minute.

The frigates are also equipped with the EDO Corporation active low frequency towed sonar to enable long range submarine detection and classification, as well as EuroTorp A244/S Mod 3 lightweight torpedoes fired from two B515 triple-tube launchers hidden behind the bulwark.

The frigates are equipped with Sikorsky S-70B naval helicopters, an international derivative of the United States Navy Sikorsky SH-60B Seahawk. The Ministry of Defence signed a contract with Sikorsky Aircraft Corporation in January 2005 to acquire six of these helicopters, which will be organic to the frigates. Each of these naval helicopters are equipped with a Telephonics AN/APS-143 Ocean Eye X-band maritime surveillance and tracking radar, a L-3 Communications Helicopter Long Range Active Sonar (HELRAS) dipping sonar, EuroTorp A244/S Mod 3 torpedoes and a Raytheon AAS-44 electro-optic system to provide infrared detection and tracking. The naval helicopters will be raised as a squadron in the Republic of Singapore Air Force and piloted by air force pilots, but the system operators will be from the Navy.

The USNS Carl Brashear (T-AKE-7) is a Lewis and Clark-class dry cargo ship of the United States Navy. The contract to build Carl Brashear was awarded to General Dynamics's subsidiary National Steel and Shipbuilding Company (NASSCO) of San Diego, California, on January 11, 2005. Her keel was laid down on November 2, 2007. The completed ship was delivered to the U.S. Navy on March 4, 2009

The Lewis and Clark class of dry cargo ship is a class of 14 Combat Logistics Force (CLF) underway replenishment vessels operated by the United States Navy's Military Sealift Command. As part of Military Sealift Command’s (MSC) Naval Fleet Auxiliary Force (NFAF), the ship's mission is to deliver ammunition, provisions, stores, spare parts, potable water and petroleum products to carrier battle groups and other naval forces, serving as a shuttle ship or station ship.