CALM

Single-point mooring (SPM) systems are designed to accommodate deep-draft tankers while they transfer crude oil and fuel oil to and from shore. Three typical designs are shown in Fig. 4: a single anchor leg mooring (SALM), a catenary anchor leg mooring (CALM), and an articulated column system. At present there are about 50 SALM and 150 CALM systems in operation throughout the world. The common features of these two systems are the rotating head on the buoy and the vertical chain that anchors the buoy to the seafloor. While a few SALM systems may have taut mooring lines for added buoy stability, all CALM systems have multiple catenary lines (or anchor legs), as the name implies. Several of the third type of SPMs, the articulated columns, have been designed and laboratory-tested but have yet to be installed offshore.