NEW MACHINE CUTS OFFSHORE TRENCH THROUGH BOULDER CLAY

A trenching machine for burying up to 60 in. dia offshore pipelines in boulder clay has been developed by Saipem S.p.A. The machine is the Ponga, a sumbersible cutter dredge with a depth capability of 200-500 ft and a cutting capability of 700-800 cu yd/hr when handling fluidized solids at a solids-water ratio of 1:6. The trencher is pulled by a winch on the service barge. It is kept on the correct route by groups of neoprene rollers on the main structure, hydraulically adjusted to conform to the contour of the pipe. The Ponga was tested on a stiff clay bottom with a shear strength of over 2500 lb/sq ft. It operated at about 3.5 ft/min, digging a ditch 12 ft wide at the top, 6 ft wide at the bottom, and about 8 ft deep. The design of the trenching machine is described further.

  • Availability:
  • Corporate Authors:

    Petroleum Publishing Company

    211 South Cheyenne, P.O. Box 1260
    Tulsa, OK  USA  75221
  • Publication Date: 1973-1-15

Media Info

  • Pagination: p. 56
  • Serial:
    • Oil and Gas Journal
    • Volume: 71
    • Issue Number: 3
    • Publisher: PennWell Publishing Company
    • ISSN: 0030-1388

Subject/Index Terms

Filing Info

  • Accession Number: 00056394
  • Record Type: Publication
  • Source Agency: American Petroleum Institute
  • Files: TRIS
  • Created Date: Jul 15 1974 12:00AM