Replacing a badly corroded tank on Sun Oil Co's 30,000-dwt tanker Western Sun meant a major cutting job for the Sun Shipbuilding and Dry Dock Co. A critical procedure in cutting the ship into sections was establishing the cut lines. To insure that the new section would fit perfectly into place, great care had to be taken in drawing cut lines on the hull that are parallel, in the same plane on both sides of the ship, and perpendicular to the centerline of the hull. A Perkin-Elmer alignment laser, with a penta prism that divides the beam in two by reflecting half the light at an exact 90 deg, was used for this procedure. The penta prism is in a rotating fixture that slides easily on and off the laser head. Use of this fixture permits rotation of the beam around the axis of the laser at an exact 90 deg. The laser beam appears on the target as a small red spot visible to everyone. Special optical accessories can focus the laser beam for use at distances as far as 1,000 feet, or bend it at an exact 90-deg angle. Other accessories are available that find the center of the beam permitting alignments to an accuracy of 10 micro in./ft. of displacement.

  • Availability:
  • Corporate Authors:

    Simmons-Boardman Publishing Corporation

    30 Church Street
    New York, NY  United States  10007
  • Publication Date: 1971-3

Media Info

  • Pagination: p. 66-67
  • Serial:
    • Marine Engineering/Log
    • Volume: 76
    • Issue Number: 3
    • Publisher: New York: Simmons-Boardman Publishing Corp.
    • ISSN: 0732-5460

Subject/Index Terms

Filing Info

  • Accession Number: 00034445
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Sep 27 1972 12:00AM