Chapter 21 - Performance enhancement in ship-handling mechanisms

Abstract

Constant research and development are being made to improve the performance of ships. This chapter discusses performance enhancement in ship-handling mechanisms. Becker twisted rudder is designed to greatly reduce rudder cavitation and to improve the maneuverability performance of a full spade rudder. With the concept of Schilling VecTwin rudders, two rudders operate independently behind a single propeller. Stern fins are fins or strips of steel welded around the stern frame of a ship. The idea is that these welded fins will direct water into the propeller disc and thus improve the efficiency of the propeller. These are cheap to fit and retrofit. Claims of up to 6% power savings have been made for full-form and medium-form hulls. Hinged tail flap in rudder can cause the turning circle diameter to be halved. The main advantage of bulbous bows is the gain in speed for sinular input of engine power. Stern tunnel is built over the propeller helping to ensure that the propeller is kept sufficiently immersed when vessel is at ballast drafts. It is good for dampening vibration forces, especially where the propeller diameter is large. Retrofits improve the day-to-day performance of a ship or possibly leading to a reduction in operational costs. This chapter discusses these ship handling mechanisms alongwith others.