船底の汚れに因る船體抵抗の増加
1934 年 1934 巻 55 号 p. 57-100
詳細
1934 年 1934 巻 55 号 p. 57-100
The effect of fouling upon the resistance of ships was examined by the towing experiments with the ex-destroyer Yudachi at various stages of fouled surface after 4, 75, 140, 225 and 375 days out of dock; the speeds experimented with were up to 20 knots at each fouled condition.
After these experiments the author studied the effect of fouling on the propulsive efficiency applying the above-mentioned results of towing experiments to the trial results of first-class destroyer.
The chief conclusions drawn from these investigations are:
(1) Frictional resistance of ships having fouled bottoms can be expressed by the following formula:-
Rf=fSV2•1,
where Rf=frictional resistance in kg.,
S=wetted surface area in m2.,
V=speed of ship in knots,
f=coefficient of frictional resistance which varies with the weight of fouled substances per unit area as shown in Fig. 6.
(2) Propulsive efficiency is affected scarcely by the bottom fouling.
