Small Propeller Cup: A Proposed Geometry Standard and a New Performance Model

A widely used technique to correct and enhance vessel performance is propeller “cup” – a curvature applied to the trailing edge of a propeller blade. Although cupping has become a regular procedure in small propeller shops, it is typically applied without any systematic rules or quantifiable understanding of its effect on performance. The traditional definitions of cup (e.g., light, heavy) vary greatly from one company to the next, and even from one project to the next within the same company. It is the goal of this paper to provide a consistent definition of cup geometry for practical use in industry, as well as a new performance model that can be used in propeller calculations.