Primitive man used simple machines such as levers, the inclined plane, the pulley, the wedge, the wheel, and axle. It was considerably later that man discovered that it was possible to employ liquids and gasses to exert forces at a distance, leading to the introduction of a complex array of new machines based upon what is now known as fluid mechanics and/or hydraulics (Hydraulic pressure, 1998). A machine that transmits pressure by a liquid is a hydraulic machine, a technique discovered by Pascal, who found that a pressure applied to any part of a confined fluid transmits to every other part with no loss. The pressure acts with equal force on all equal areas of the confining vaults and perpendicular to the walls' in other words, pressure results from the interactions of pipes and cylinders and produces motion of various types (Hydraulic pressure, 1998). While hydraulics are regularly employed in a wide range and variety of industrial settings, this brief report will offer an overview of the current state of hydraulics in the marine industry. It will demonstrate that the applications being employed and developed in this single industrial sector are extensive and varied.
Progress is the "name of the game" in the hydraulics industry today, where new technologies, new design strategies, and new types of partnerships with customers are fueling change (Gilchrist, 1999). Mobile hydraulics, or hydraulics used on non-stationary equipment, have become the focus of intensive research and development activities in recent years. A major change in the deployment of hydraulics in the context of marine activities (including submarine sonar and propulsion systems, missile launch systems, cargo handling systems and aircraft elevators) has been the increase in pressure. In the 1960s, many of these mobile systems were operating at 2,000 psi (pounds of pressure per square inch); today, the majority of such systems operate in the range of 3,250 to 3,...