Indication of Effective Speed and Deceleration to Vessels in Port Approaches

Abstract

1. INTRODUCTION. The controlled deceleration of a ship in the final approaches to the berthing area is of crucial importance to ensure that the ship is stopped in time and can be manoeuvred to the berth by assistant tugs. Shipborne instrumentation cannot be relied upon entirely to assist the ship handler in this aspect because, with very few exceptions, it does not give sufficiently accurate information at very low speeds and minimum underkeel clearances. Traditionally of course, it is part of the ship handler's skill to judge the ship speed and deceleration by eye and it is important that this skill is finely developed to arrive correctly at the manoeuvring area. It is however the case that the judgment of very low speeds becomes increasingly difficult with the larger ships, yet it is with such ships that this judgment is the most critical.