ROUGH PROPELLER PENALTIES

The first part of the paper offers the ship operator a standard procedure for the measurement of propeller blade surface roughness in service, either using a protable stylus instrument or the Rubert comparator gages. From the single-number average propeller roughness (APR), the power penalty can be simply calculated by means of a nomograph. The first part closes with guidelines for the good husbandry of the blade surface finish. Both the two-parameter output from the stylus instrument and the comparator gages are correlated with Musker's equivalent height parameter h' and the second part of the paper shows how these measurements may consequently be related to increments in airfoil section drag. Use is made of Lerbs' equivalent profile method to convert the enhanced section drag into a power penalty. The second part also includes a discussion of the general problem of calculating the effect on power of a rough propeller working behind a rough hull.

• Supplemental Notes:
  • Transactions paper
• Authors:
  • Townsin, R L
  • Spencer, D S
  • Mosaad, M
• Publication Date: 1985

Media Info

• Features: References;
• Pagination: 23 p.
• Serial:
  • Society of Naval Architects and Marine Engineers-Transactions
  • Volume: 93
  • Publisher: Society of Naval Architects and Marine Engineers

Subject/Index Terms

• TRT Terms: Losses; Propellers
• Old TRIS Terms: Propeller cleaning; Propeller roughness; Propulsive power; Speed loss
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00651466
• Record Type: Publication
• Source Agency: Maritime Technical Information Facility
• Files: TRIS
• Created Date: Jul 21 1994 12:00AM