Parametric Analysis of Ship Squat in Shallow Water by Model Test

Reduction of distance between the ship fl oor and the seabed when a ship is moving forward is called squat. Squat causes grounding of the ship that may result in severe damage to the ship and in extreme cases may lead to complete loss of port or channel capabilities. If a ship moves in the shallow waters then the velocity of the fl uid fl ow at the bottom of the ship increases and the pressure decreases which in turn leads to the decrease of buoyancy force and the increase of the ship draught. The purpose of the presented research was to determine the squat for vessels with the Series-60 hull forms in various depths by experimental methods. For this reason, a set of facilities for testing the ship movement in shallow waters were prepared and then the measurement tools were calibrated. A series of models of the vessel were manufactured and many tests were carried out. Disregarding the non-acceptable data, the test results were analyzed in various depths and draughts. To generalize the test results, some new non-dimensional squat parameters were introduced. The examination of the test data through regression analysis resulted in an empirical equation for ship squat as a function of ship parameters as well as depth of the water