Wave Scatter Diagram and Standard Wave Data

A wave scatter diagram is a table of the joint probability of occurrence of significant wave height and a characteristic wave period for a defined sea area and period of the year. It is the statistical description of the environment that ship structural design, fatigue assessment and dynamic stability assessment all take as input, and the choice of diagram often matters more to a result than the analysis method applied to it.

The North Atlantic scatter data published by IACS is the standard design environment for unrestricted service, chosen because it represents a severe trading area rather than a typical one. World-wide and site-specific scatter data exist and give materially lower loads, which is why the applicable diagram is stated with any load or vulnerability result rather than assumed.

The full article will cover the construction of a scatter diagram from measured and hindcast data, the definition of significant wave height and of the zero-crossing and peak periods, the IACS North Atlantic data and where they are mandated, the difference between design and operational scatter data, and the use of scatter data in the second generation intact stability criteria.