舶用プロペラの損傷およびその補修技術の現状 Propeller Damaged and Repair Techniques at Present
Authors have been engaged in propeller repairs for many years, and investigations of damaged propeller were made on 1, 274 propellers repaired by the authors in the last 18 months.<BR>As the results, many damaged propellers from small to large size suffered most from bent and/or missing with cracks at both leading and trailing edges of the blades due to collisions against foreign bodies while in ahead or astern conditions.<BR>Nowadays almost of all of vessels are operated without having spare propellers. Importance of the repair techniques, therefore, becomes more and more conspicuous for working propellers having various chance of damages, in a limited time. Authors, specially, mention particulars to be considered for achieving high quality repairs as follows; -<BR>1) Repair step, process and procedure for bent and/or missing parts with cracks<BR>2) Restoration and welding repair techniques for damaged propellers<BR>3) Key points for the damaged propeller repair works<BR>4) Studying about acceptable or unacceptable welding repairs<BR>5) Consequential cracks originated from improper welding<BR>Among the particulars above, authors have been paying great attentions to the improper welding works which caused by an un-desirable stress remained at the repair area, which may generate consequential cracks at the part in future operation of the vessels, and suggest that repairers who intend to carry out welding repairs should have qualification tests by classification societies etc. for their welder, and the welding repairs should be conducted by the skillful welder having such certificates.
日本舶用機関学会誌 33(9), 653-664, 1998-09-01
The Japan Institute of Marine Engineering