A wave energy converting apparatus (44) and its associated tension mooring system (50) is described. The wave energy converting apparatus (44) comprises an elongate support structure (45) designed to extend above a mean water level in the ocean. The support structure (45) has a submerged member (46) provided in connection therewith below the mean water level. A float member (48) of positive buoyancy is slidably mounted on the support structure (45) so as to be movable in a vertical direction. The apparatus (44) also comprises a linear electric generator (49) having a stator provided in connection with the support structure (45) and a translator integrated into the body of the float member (48). Differential motion of the float member (48) relative to the support structure (45) results in the generation of electrical power by the linear electric generator (49). The tension mooring system (50) comprises a cable (51) extending from a ballast means (52) to a counterbalancing means (53) adapted to be suspended from the submerged member (46) via a pulley mechanism (54). The tension mooring system (50) allows the apparatus (44) to be 'tuned' to the prevailing ocean conditions.