T. H. HAVELOCK 
A third example of this series was also examined, because it has 
a larger beam and only half the draft: namely Model 2038C, with 
a, = —0.5; length = 27 = 16 ft; beam = 26 = 1.75 ft; draft = d = 0.5 ft. 
Further details with the measured trim, may be found in Wigley’s 
paper [4]. 
In this case for the small correction Rd‘, the value of d' was 
taken to be 2.5 inches. The calculated trim at f = 0.5 was found to 
be 4.75 inches, the measured value being 4.37 inches. The com- 
plete results are shown in Fig. 2, the full curve being the measured 
values and the broken curve those found by calculation. 
Considering the three cases together, the general measure of agree- 
ment between calculated and experimental curves is perhaps as good 
as could be expected from a first-order theory with the various ap- 
proximations involved and including the neglect of viscosity effects. 
The order of agreement is much the same as that between calculated 
and measured curves of wave resistance, the greater discrepancies 
in trim occurring at speeds at which there are corresponding differ- 
ences between calculated and measured resistances. It may be said 
that the present calculations afford further confirmation of the ap- 
proximate theory of wave resistance. 
REFERENCES 
T.H. Havelock, Zeit. f. Ang. Math. Mech., 19, p. 202 (1989). 
T.H. Havelock, Proc. Roy. Soc. A, 138, p. 340 (1932). 
W.C.S. Wigley, Cong. intern. Ing. Navals, Liege, p. 174 (1939). 
W.C.S. Wigley, Trans, Inst. Nav. Arch. 84, p. 52 (1942). 
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