ICEBREAKING WITH MODELS AND ON FULL SCALE

After a brief general discussion of research on icebreaking, the Authors give an account of the 1977 research voyage of the twin-screw icebreaking supply-ship Werdertor (1,495 tons displacement) off Spitzbergen, together with an account of tests with a model of this ship in the HSVA ice-tank. The voyage was a co-operative effort by the ship's opeators (the Offshore Supply Association), Germanischer Lloyd, the Jastram company, and the HSVA. The full-scale research programme, under the guidance of the HSVA, was an extensive one, and the results presented in the paper are mostly those relevant to model/ship correlation. (for the manoeuvring tests on the Werdertor in ice, one of the ten itmes in the research programme.) In model tests on icebreaking ships, most experimental ice-tanks have concentrated on resistance tests; however, the HSVA carries out propulsion tests in ice as a standard procedure. How accurately the model results can be correlated with the full scale has been a difficult question, and the present work has, for the first time, provided full-scale propulsion results for a ship whose model results were available; the discrepancies between model and full scale were below 10%. These investigations have inter alia confirmed that, because of the effect of ice upon propeller efficiency, model tests for power-requirement predictions must include propulsion tests in ice. A brief account is included of tests, during the research voyage, of a system developed by Jastram and the HSVA for reducing frictional resistance of ships (and offshore structures) in ice. The system employs an air/water mixture which is pumped out through jets in the ship's forebody. Although the results of the model/full-scale comparisons have been satisfactory, the Authors recommend that every opportunity should be taken for making further comparisions. A theoretical basis for the icebreaking processes should also be sought; work to this end is proceeding at the HSVA. Order from BSRA as No. 52,293.

  • Corporate Authors:

    Springer Verlag

    175 5th Avenue
    New York, NY  USA  10010
  • Authors:
    • Schwarz, J
    • Hoffmann, L
  • Publication Date: 1978

Language

  • German

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00310803
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: May 7 1980 12:00AM