In the second set of experiments, a heave motion FB was
tested. The initial draught of the FB was 0.4m(dr/d = 1/5). Iron
rails were attached to the walls of the flume to restrain horizontal
and rotational motion of the structure, while greased pneumatic
wheels were attached on the structure to allow unrestrained vertical
motion with minimum friction (Fig. 4). The weight of the
structure was 2240 kg while the centre of mass was 0.2m below
the free surface due to the extra uniform weight put inside the