NOVELTY - The medium has a set of instructions for receiving information defining characteristics of wave action proximate to a watercraft (400), where the watercraft rolls in response to the wave action, and includes a pendulum to swing in response to the wave action. Roll characteristics of the watercraft are tuned (410) to the characteristics of the wave action. The pendulum is tuned (420) to the characteristics of the wave action. Center of gravity is determined for metacenter of the watercraft. Kinetic energy of the watercraft-pendulum roll mismatch is converted (430) into electrical energy.    USE - Non-transitory computer-readable storage medium for extracting tuned rolling wave energy from bottom of a sea and converting the wave energy into electrical energy.    ADVANTAGE - The medium has a set of instructions to extract wave energy that provides benefit of trochoidal motion for wave particles by coupling the trochoidal motion to the rolling action of waves, so that energy extraction components are tuned for incoming waves, thus converting the wave energy more efficiently into electrical energy. The watercraft includes multiple components supported by wing tanks, and the components of the pendulum, a drive system and an alternator are enclosed within a housing structure such as hull or superstructure of the watercraft, so that the housing can prevent seawater or corrosive elements from reaching the components, thus reducing the maintenance of the components.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of a system for extracting tuned rolling wave energy and converting the wave energy into electrical energy.    Step for receiving information defining characteristics of wave action proximate to a watercraft (400)    Step for tuning roll characteristics of a watercraft to characteristics of wave action (410)    Step for tuning a pendulum to characteristics of wave action (420)    Step for converting kinetic energy of watercraft-pendulum roll mismatch into electrical energy (430)