Three heavy-load-moving systems are outlined here, two for horizontal transfer movement and one for hoisting or lowering. All schemes use hydraulic jacks for muscle and for control. All are aimed at low capital investment and maximum flexibility. Any specific application of a system will require that it be custom designed to suit the specific needs of the yard, with capacity for expansion at a later date. The Hydranautics Gripper Jack is a tool for applying very large traction forces to transfer a ship or module structure horizontally. The basic elements in the tool are a hydraulic gripper and a jacking cylinder. The jacking cylinder provides the traction force which moves the load. The gripper is a movable friction lock which anchors the jack and reacts the jacking thrust into a stationary jacking flange. Usually a number of gripper jacks are employed to move a load. The load normally rests on two or more wood sliders which travel on greased skid ways. Integral with each skid way are jacking flanges on which the jacks are mounted. The jacks push against the sliders which support the load or against the load itself, and react their thrust through the grippers into the jacking flanges. Gripper clamping is done through direct hydraluic means without force-multiplying linkage. The total clamp force on the jacking flanges will often exceed the tonnage being moved by a factor of two. For example, grippers totalling 2,000 tons of clamp force may be used to move a 1,000-ton load. Systems have been produced using multiple jacks and single or multiple power-supply units to suite a wide variety of applications, such as: 1) Moving 6,000-ton offshore drilling structure sideways onto launching ramp. 2) Bidirectional moving of ship sections and barges. 3) Moving 12,000-ton offshore oil platform "jacket" from building ways to launch barge. 4) Moving stern sections for tandem construction. 5) Moving 15,000-ton ship sections from ground ways into floating dry dock. 6) Moving 11,000-ton ship down incline slip way, using "extrusion" technique of construction.

  • Supplemental Notes:
    • Presented March 14, 1975 to the Philadelphia Section of SNAME.
  • Corporate Authors:

    Peat, Marwick, Mitchell and Company

    1025 Connecticut Avenue, NW
    Washington, DC  United States  20036
  • Authors:
    • Chambers, H B
  • Publication Date: 1975-3

Subject/Index Terms

Filing Info

  • Accession Number: 00126956
  • Record Type: Publication
  • Source Agency: Society of Naval Architects and Marine Engineers
  • Files: TRIS
  • Created Date: Nov 5 1975 12:00AM