Cross sea

Common card · No. 482040

A cross sea (also referred to as a squared sea or square waves) is a sea state of wind-generated ocean waves that form nonparallel wave systems. Cross seas have a large amount of directional spreading. This may occur when water waves from one weather system continue despite a shift in wind. Waves generated by the new wind run at an angle to the old. Two weather systems that are far from each other may create a cross sea when the waves from the systems meet at a place far from either weather system. Until the older waves have dissipated, they can present a perilous sea hazard. This sea state is fairly common and a large percentage of ship accidents have been found to occur in this state. Vessels fare better against large waves when sailing directly perpendicular to oncoming surf. In a cross sea scenario, that becomes impossible as sailing into one set of waves necessitates sailing parallel to the other. Cross seas present a particular hazard for small boats and swimmers, since they can...

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