The wide coverage and the untapped tremendous energy amount stored by the oceans makes the harness of ocean waves for electricity-generating is promising. Most techniques of wave energy converters (WECs) include a pneumatic or hydraulic interface between the wave converter and the electric generator for electricity-producing smoothly. But, a direct power take-off interface may be a way of increasing the capture and converting efficiency of wave power. This study was carried out to design, manufacture, performance analysis, and evaluation of capture and transforming wave energy efficiency for a new model of a single-axis wave energy converter (WEC) that extracts wave energy directly by a mechanical power take-off interface. Eventually, the study concluded that there is a specific configuration of the converter fits each wave condition for optimum performance that able to work by the efficiency of 10% to capture and convert the wave power. Also, the optimum performance for a selected place for installing the device should be performed starting at the design stage. One of the major condition in the design stage of the proposed WEC unit for the optimum performance is that the appropriate length of the WEC buoy (i.e., the length that is parallel to the wavelength propagation direction), should be designed with a length is equal or among (29.4 to 33.3 %) of the prevailing wavelengths.