To support the build of a new Joint Support Ship (JSS), the team at the Vancouver-based Seaspan shipyard wanted to find a more effective way to keep the ship level throughout the project. To achieve this, an Enerpac EVO Synchronous Lifting Pump and 12 High Tonnage Hydraulic Lifting Cylinders were specified and supplied by local Enerpac distributor Hyseco.
The JSS vessels will provide an important supporting function to the Royal Canadian Navy by providing marine fuel, provisions, and support for training and humanitarian operations. When fully constructed, the JSS will weigh an estimated 10,895-ton, and measure 173.7m length with a breadth of 24m.
JSS vessel construction supported by theEnerpac EVO System
As any large-scale ship build progresses, the increasing weight can cause the ground underneath to move. If ignored this has the potential to put a strain the integrity of the ship’s structure. Previous methods of levelling the ship involved deploying a team of people manually adjusting each lift point to achieve the required height, and to minimize side load.
Effective, safe, and precise movement of such a large and heavy object requires exact control and synchronized movement of all lifting points. The EVO system works using a PLC (Programmable Logic Controller), enabling each of the 12 lifting points to be monitored and controlled by a single operator.
The 12 cylinders used were Enerpac HCG1506-Series single acting models. Each of these are capable of supporting a load of up to 168 tons and can withstand 10% side-load over the full stroke. On the body and plunger, the cylinders feature a tough and anti- corrosive nitrocarburized finish. Inside, they incorporate polymer bearings to prevent scouring from side load. The cylinders were positioned between the footings and frame assembly supporting the ship. Each point was adjusted by automatic control of the oil flow to each cylinder – causing the cylinder plungers advance and retract accordingly. The EVO pump maintains accurate positional control within 0.040 inches (1 mm) between lagging and leading cylinders and includes built-in warning and stop alarms for optimum safety.
The EVO System provided a safer solution than traditional methods by reducing manual intervention. Using just one operator to control 12 lift points from a single intuitive interface was also more productive and accurate – ultimately helping to maintain structural integrity as the build progressed.
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