The STC model is shown in Fig. 5, and each part of themodel and the
material used is illustrated. The coordinate system is also shown. The
still water levels for the MWL and SUB modes are shown with blue
lines in Fig. 5 and Fig. 6. The tower and main buoyant part of the floater
are composed of PVCmaterial, and the cylinder in the middle part of the
model (i.e., the upper part of the spar floater) is composed of aluminum
alloy. The aluminum alloy has a low weight but high stiffness that allows
the installation of load cells between the two bodies. The torus is
made of two materials: the core is composed of Dyvincell, and aluminum
alloy plates are located on the top and bottom of the core.