Study on Prediction Method for Shipping Water Load and Volume due to Green Sea

Model tests were carried out in order to develop a method for long-term prediction of shipping water load and volume on bow deck. Models of a cargo ship and a tanker for Japanese domestic voyage were used, the former in regular/irregular waves, the latter in irregular waves. As for the cargo ship the bow flare form and bow height were varied from the original one to investigate the effect of them on the load and volume on the bow deck. The theory of “flood waves”, which gave a good estimation for these quantities of the tanker in the previous paper, was compared with the experimental result of the cargo ship. It was confirmed that this theory can also be well applied to the cargo ship at various bow flare form and bow height.The effect of flare form and bow height on the ship motion, relative water height at bow, shipping water load and so on was discussed. It was found that the effect of bow flare form on shipping water load, volume and pressure is small compared to the effect of bow height.Based on the result that shipping water load and volume is proportional to the square of the water elevation over the bow top, their probability density functions in short-term prediction were proposed. It was confirmed that proposed functions show a good agreement with the measured distributions, especially the tails of them, better than conventional equations. Using these functions, long-term predictions of shipping water load and volume were carried out.