Energy efficiency design index vs. safe manoeuvring in adverse conditions

摘要

The International Maritime Organization (IMO) developed new regulations on energy efficiency for new ships, called the Energy Efficiency Design Index (EEDI), which entered in force on 1 January 2013 for main ship types. During the development of this new IMO regulation, some flag state administrations as well as ship owners' associations underlined the need to provide sufficient power to ensure safe manoeuvring in adverse conditions. The concerns of the maritime community regarding possibly underpowered vessels have prompted the International Association of Classification Societies (IACS) to develop a guideline to evaluate whether a ship has sufficient power to safely manoeuvre in adverse conditions. Due to the complexity of the task, IMO implemented - as interim measure - only requirements for oil tankers and bulk carriers. The paper documents that this interim measure is in conflict with the EEDI regulations for smaller ships. Noting the current discussion on the definition of adverse conditions, the paper presents an application of the simplified assessment, following IMO Interim Guidelines and taking into account the ship and propulsion systems particulars to predict forward speed in head waves. The paper also presents the application of a tool to perform the comprehensive assessment and compares the results with the other assessment levels.