To demonstrate the usefulness of the program for predicting the ship's squat, a standard Series 60 hull with a block coefficient CB = 0.594 in shallow water was investigated. The corresponding model had a total weight W = 4271 N, a length at waterline L = 4.689m, a beam B = 0.6252 m, and a draft T = 0.25 m. For a configuration of the Duisburg Shallow Water Towing Tank (VBD) at a waterdepth h = 2T = 0.5 m the sinkage and trim are computed by using BEShiWa and then compared with those from the model tests. The results are shown in Fig. 1. It can be observed: (i) A good agreement between computation and model experiment was achieved in the whole speed range, i.e. in the steady subcritical and supercritical speed range as well as in the unsteady transcritical one, particularly for the trim. (ii) The sinkage curve has a maximum near the bifurcation point at the transition between the subcritical and transcritical speed range. But more impressive is the sudden change of the trim from a small bowdown value to a large bowup one at this bifurcation point. (iii) The trim remains more or less to the same value in the transcritical and supercritical speed range. The sinkage seams to have a minimum value near the bifurcation point at the transition between the transcritical and supercritical speed range. (iv) The sinkage in the supercritical speed range is small and agrees not so well with the measured value. One reason may be the planning effect at such a high speed. This effect has been not explicitly handed in the present program.
Fig.2 
Comparison of the measured, computed, and analytically calculated sinkage for an inland vessel in shallow water of four depths 
In order to examine the applicability of the computer program BEShiWa in the praxis, three example ships are systematically investigated. One is an inland passenger ferry that operates on the river Rhine. The second is a seagoing vessel and the third a PANMAX containership. The main dimensions of the three ships are listed in Table 1.
Table 1 : Main dimensions of investigated ships

Inland vessel 
Seagoing ship 
PAN MAX
Containership 
LWL 
109.28m 
137.15m 
280m 
B 
11.45m 
19.05m 
32.2m 
T 
3.0m 
8.10m 
11m 

For the four waterdepths investigated, Fig. 2 compares the measured (+), and the computed (o) mean sinkage as well as the analytical value from the onedimensional hydraulic formula (solid line) according to the geometrical configuration in the VBD tank. Obviously, there is a remarkable agreement between the computation and model experiment for the subject inland vessel throughout these four waterdepths. The difference between the measured values and the analytical solutions by Constantine (1960) is practically not acceptable. Moreover, there exists a maximum of the depth Froude number in the analytical solution. Beyond this point the sinkage is not defined. It contradicts the physics and the observation in model tests.
Fig. 3 compares the measured (+) and calculated (o) squat defined in Section 2.7, as well as the estimation from the empirical formula (solid line) according to the geometrical configuration at the VBD tank. Again, there is a considerable agreement between the computed and measured squat for the subject inland vessel at the four waterdepths. In comparison with the measured values the empirical formula given by Barrass (1979) is only acceptable at a lower speed and in a deeper region. In these two cases the squat is less important in the praxis.
