As the largest joint venture with 70% petroleum production inland, Vietsovpetro now has become main force of Vietnam’s petroleum industry and economy. Via a specific and comprehensive consideration, Yiulian Dockyards (Shekou) Limited confirmed repair of its FSO Ba Vi with regard of the new breakthrough in the offshore market abroad. Among 1700tons steel renewal, pipe system clean, renewal of zinc anode, the large amount of valve overhaul and other repair, the sand blasting and painting in oil tank and water tank is recognized as a great challenge because of the quite strict requirement for the FSO. Besides that, the overhaul of meter prover system resulting from self special structure also put us into some difficulty. Nowadays Single point mooring is also the preferred option for a lot of deep water field developments in combination with an FPSO for production and storage. However, this is the first trial for our shipyard to deploy this kind of system. The system comprises a central element adapted to be anchored by means of anchor cables and a buoyant outer element rotatably arranged around the central element. The outer element comprises an open beam structure connected to a large diameter outer ring. Foam-filled fenders are secured to the large diameter outer ring. Preferably the fenders act as floats. Although it looks simple, the hydrodynamics are not simple at all. Even in collinear environments of wind, waves and current ‘fish-tailing’ can occur of the shuttle tanker with its bow hawser connected to the buoy. The (viscous) damping forces that control these motions are extremely complex and require special attention in the numerical simulations of single point moorings. The demonstrated and anticipated advantages of using an SPM include decreased cost, predictable mooring loads and cage movement, and reduced environmental impact. Especially when a ship moored to the system hits the system, the risk of damage to the ship or the system is substantially reduced as compared to the conventional single buoy mooring systems.