Online ISSN : 1884-2062
ISSN-L : 0514-8499
GMおよびD/d比を用いた船幅の決定法について

ジャーナル フリー

1965 年 1965 巻 118 号 p. 337-347

At the beginning of the initial design of ship, the breadth of ship has been determined by the formulas B=L/10+α (α=4.56), B=L/9+β (β_??_3.2) or L/B ratio (6.57.5 for cargo boat). But the above formulas have no connections with KG, GM and the freeboard. The author has delived the relation between B and D from the GM equation. The result is as following.
[2Q/GM (d/D) D+1] 2-4QP/GM2 (d/D) 2B2=1
where
P=Cw/Cb (0.0106+0.0727 Cw) =1/R
Q=n (d/D) - (d/D) 2Cw/Cb+Cw
The above equation is a hyperbola of B and D. So B can be put for an asymptote of this hyperbola.
B=√RQ/L/Dratio·L+GM (d/D) √R/4Q where L=D×L/D ratio.
The above equation can be expressed as following.
B=L/const1+GM+ (d/D) const2 (1)
Flush DK Shelter DK Three isl Well DK Oil Tanker
(KG/D) (0.60) (0.60) (0.65) (0.52)
Const1 8.38.7 7.78.2 8.48.8 12.513.2
Const2 4.64.5 4.54.4 4.2 5.7
Fore figure is U shape, aft figure is V.
The const1 varies by the D/d ratio and KG/D, but the const2 varies very small.
When the second term of the equation (1) is large in case of an oil tanker, a correction value [= (the second term of eq (1)) 2×1/2B] must be subtracted from B in the equation (1).
The author has drawn the curves of R and Q for the general application.