Design Procedure of 4-Bladed Propeller
Marine propellers, although submerged in water aft of the ship, form an integral part of a ship and play a vital role in ship propulsion. Much has been said and published on the development of the marine propeller from the time of antiquity to the present age, but there is more to be done. Therefore, this paper focuses on the design procedure of four bladed marine propellers with specific interest on engines with 85Bhp and ship speed of 30knots for the design of the fixed pitch propeller. This work covers the basic principles underlying the design from the beginning to the end. Thus, this work used the Bp standard chart using the optimum design line to carry out the design analysis of propellers for a ship with a detailed calculation of the various stages involved in the derivation of the basic propeller. The result of the work thus shows that for a propeller with Blade area ratio of 0.55, the open water efficiency is 73%. This means that irrespective of the initial cost of designs and manufacturing this type of propeller, the development of maximum efficiency should be the pursuit of the designer, the manufacturer and the user.
Keywords: 4-Bladed propeller, efficiency, pitch ratio, expanded area, developed area, projected area