A "natural trim"--phenomenon occurs in all waterballasting and leaking sequences. The trim angle that develops, can reach an alarming magnitude. This varies from case to case, depending on configuration and sub-division of the hold, free versus controlled flooding, etc. In the early days of submersible drilling barge development, experimental design found the answers to some of the operational problems resulting from this cause. A satisfactory theoretical explanation however has never been advanced. The phenomenon has been consistently misrepresented in the technical literature on mobile units, as an "instability" problem. In reality, it is purely a floatation and trim problem, and should be treated as such. Accurate solutions can be found in terms of a simple extension of ordinary hydrostatic theory. This extension of theory is hereby presented. It yields a perfectly general solution to the problem theta = f(p), where (theta) is the inclination that develops, and (p) is the waterballast weight admitted. While no longer acutely needed in the design and operation of semi-submersibles, which simple "outgrew" the case, it should still be of considerable interest to anyone planning the installation of a subsea facility, by means of remote control flooding and free fall to bottom. Of even greater immediate interest however is the fact, that the new method is directly applicable to the vaxing problem of attitude control in small submarines. It is hoped, that this paper may help the further development of truly practical submarine workboats in the gas/oil field. The paper includes a basic, pictorial review of some of the more relevant hydrostatic relationships.

  • Supplemental Notes:
    • Presented to the Spring Meeting of the Pacific Northwest Section of SNAME, May 14, 1977 in Victoria, B.C.
  • Corporate Authors:

    Society of Naval Architects and Marine Engineers

    601 Pavonia Avenue
    Jersey City, NJ  United States  07306-2907
  • Authors:
    • Bloemhard, W J
  • Publication Date: 1977-5-14

Media Info

  • Features: Figures;
  • Pagination: 26 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00164849
  • Record Type: Publication
  • Source Agency: Society of Naval Architects and Marine Engineers
  • Files: TRIS
  • Created Date: Oct 29 1977 12:00AM