Since the 18th century, hydraulic ram pumps have harnessed the water hammer effect to move water in a renewable and sustainable manner. This article demonstrates that, by substituting the pressurised water delivery system for an energy conversion mechanism, the operating principles behind hydraulic rams can also be adopted for the purposes of providing renewable energy. An experimental study involving a small scale model device driving a piston-crank mechanism is presented to demonstrate the concept. The peak mechanical efficiency of the test rig was found to be 25.7%, with the time-averaged efficiency varying from 0.3 to 1.7%. (C) 2018 Elsevier Ltd. All rights reserved.