Abstract

Recent research has demonstrated that extreme waves, waves with crest to trough heights of 20 to 30 meters, occur more frequently than previously thought. Also, over the past several decades, a surprising number of large commercial vessels have been lost in incidents involving extreme waves. Many of the victims were bulk carriers. Current design criteria generally consider significant wave heights less than 11 meters (36 feet). Based on what is known today, this criterion is inadequate and consideration should be given to designing for significant wave heights of 20 meters (65 feet), meanwhile recognizing that waves 30 meters (98 feet) high are not out of the question. The dynamic force of wave impacts should also be included in the structural analysis of the vessel, hatch covers and other vulnerable areas (as opposed to relying on static or quasi-dynamic analyses).

Introduction

Recent research by the European Community has demonstrated that extreme waves—waves with crest to trough heights of 20 to 30 meters—occur more frequently than previously thought (MaxWave Project, 2003). In addition, over the past several decades, a surprising number of large commercial vessels have been lost in incidents involving extreme waves. Many of the victims were bulk carriers that broke up so quickly that they sank before a distress message could be sent or the crew could be rescued.

There also have been a number of widely publicized events where passenger liners encountered large waves (20 meters or higher) that caused damage, injured passengers and crew members, but did not lead to loss of the vessel. This is not a new phenomenon; there are well-documented events dating back to at least the early 1940s.

These two facts, vessel losses combined with knowledge that waves larger than previously considered likely may be encountered, suggest that reviewing vessel design criteria may be necessary. (Smith, 2006).