A Three-Dimensional Time-Dependent Icing Model for a Stern Trawler

A full-scale spray flux equation has been derived for ship-generated spray using spraying data obtained from model-scale experiments. Using this equation, droplet trajectory modeling, and spray mass continuity, a full-scale spraying model, which includes the effect of wind drag, has been developed for the stern trawler Zandberg. This spraying model has been incorporated into an icing model for the same vessel. A three-dimensional grid cell mesh is superimposed on the surface of the ship so that the local spray flux and icing rate on each grid cell can be calculated using the combined spraying and icing models. The disappearance of the Blue Mist II is used as a case study to illustrate the performance of the icing model. Under these severe icing conditions with off-head winds, the model predicts an icing rate of more than 13 tonnes per hour for the Zandberg, and the ice distribution is highly asymmetrical. This ice loading is the most dangerous condition for the ship's stability.