Section 11 Green water and wave impact

11.1.1 Green water is taken to mean the overtopping by water in severe wave conditions, resulting in loading on the deck structure and any exposed equipment. Significant amounts of green water will have an impact on the vessel deck structural design, accommodation superstructure, equipment design and layout and may induce vibrations in the hull. The effects of green water loading should be accounted for, where applicable.

11.1.2 The requirements of Pt 10, Ch 2, 3.8 Dynamic local loads, Ch 2,7.4 and Pt 10, Ch 3, 6 Evaluation of structure for sloshing and impact loads are to be complied with, see also Section 5 and Section 6.

11.1.3 Appropriate measures should be considered to minimise green water effects on the structure and critical equipment, including bow shape design, flare, breakwaters and other protective structure such as turret housings. Adequate drainage arrangements must also be provided, see also Pt 4, Ch 7, 10 Scuppers and sanitary discharges.

11.1.4 Wave slamming effects should be taken into account for both hull and mooring structure design. Locations on the hull which may be subject to effects of wave impact include the forward bottom structure, stern structure, bow flare and bow side. The effects of slamming on the structure should be considered in design, particularly with regard to enhancement of global hull girder bending moments and shear loadings induced, local strength aspects and limitations to ballast draft conditions.

11.1.5 It is recommended that provisions are made during model testing, for measurement of both green water loading and wave slamming pressures which can be used for local structural design.