On the manoeuvring performance of a ship with theparameter of loading condition

Abstract

SummaryOn the prediction of ship manoeuvring performance at the initial design stage, it is considered that a loading condition is one of the important parameters caused for the manoeuvring characteristics. For the prediction of ship manoeuvrability with high accuracy, it will be required to estimate the hydrodynamic forces acting on ship accurately in any loading conditions.In this paper, the approximate formulae for estimating the hydrodynamic forces acting on ship in any loading conditions such as half loaded, ballast and trim by stern conditions are proposed. These approximate formulae were derived from the results of model test. The model ships used for obtaining the hydrodynamic forces are 13 ships consisting of general cargo, car carrier and RORO ships. And the model test was carried on 13 ships for fully loaded condition, on 11 ships for ballast condition and 5 ships for half loaded condition.By comparing with the measured results of free running model test, the prediction results agree well with model test results. Therefore, this method will be useful for practical prediction of manoeuvrability for conventional ship at the initial design stage. However since those approximate formulae have been investigated on model ship, there still remain some problems to be solved such as a correlation, scale effect and so on, to predict the manoeuvring performance of full scale ship.

Maneuverability of Ships with small Draught in Steady Wind

“…The C n , S n , t n , u n , and v n coefficients are obtained from the data shown in [9]. The rudder forces and moment are defined by Kijima et al [8] as a function of a H , x' H , and t R coefficients, rudder normal forces F N , and the rudder angle δ as follows equation (9), (10), and (11).…”

“…The sub script of each coefficient in the above equations indicates the derivative of the hull force and moment components to the drift angle and yaw rate, respectively. Following the MMG model proposed by Kijima et al [8], the propeller thrust is estimated based on the thrust coefficient as follows equation (7). The propeller thrust depends upon the thrust deduction factor coefficient t P , the propeller revolution n, the propeller diameter D P , and the thrust coefficient K T as a function of the advance coefficient J.…”

“…The ship heading angle is noted by ψ, and the rudder angle is indicated by δ. The mathematical equations for the three degrees of freedom for ship motion in maneuvering are as follows [8]:…”

“…Ship maneuverability is usually modeled with three degrees of freedom in mathematical equations: surge, sway, and yaw motions. The Mathematic Modeling Group (MMG) formulation proposed by Hirano et al [7] and Kijima et al [8] was used to govern the maneuvering mathematic model. Here, two coordinate systems are necessary for ship movement.…”

“…The advance coefficient, including the wake fraction, is also determined in accordance with the MMG model. Here, the thrust coefficient is calculated by a polynomial regression equation based on the experimental data of a B series propeller as follows [10] equation (8).…”