The single point calm buoy has been developed for many years in the word, but there are only two calm buoys system used in China, Maoming and Weizhou. DMAR Engineering Company did a research project about Calm Buoy for the further potential application in China
The paper first overview the development of the calm buoy system: wheel and rail buoy, turntable and turret buoy. It also addresses the key technology of the clam buoy. DMAR's study follows a new configuration and gives detailed hydrodynamics of the calm buoy's skirt geometry and its submarine hose system.
Numerical simulations have shown that the dimension of the skirt has significant influence on its hydrodynamic properties, such as heave motion period, which also affect the performance in heave motion control. The paper studies the three diameter ratio (Db/Ds) and gives the detail results for design purpose.
The heart of each buoy is the product transfer system. In this study, the riser system is the main subject of the research. The submarine hose's configuration design and strength analysis are big challenges for calm buoy in shallow water, as there is a big bending moment on the hose. The global performance of the submarine hose will be studied by the Orcaflex.
A single point mooring (SPM) is a loading buoy anchored offshore and serves as a mooring point and interconnect for tankers loading or offloading gas or liquid products. Compared to the port terminal facility, the SPM has many advantages:
No water depth limited
No tanker heading limited
More safety
Short building period
SPMs are the link between geostatic subsea manifold connections and weathervaning tankers. They are capable of handing any size ship, adaptable in any water depth, where no alternative facility is available. There are mainly three types of SPM buoys since the first loading buoy came out in the 1920s,:
CALM (Catenary anchor leg mooring): It consists of a buoy anchored by 4 or more chains extending in catenaries to anchor points on sea floor (See Fig.1)
VALM (Vertical anchor leg mooring): It consists of a buoy with 3 or more vertical pre-tensioned chains anchored on seabed. (See Fig.2)
SPMT (Single point mooring tower): It consists of a rigid structure erected on seabed and extended up above water surface with a mounted turret on a swivel.
