556
moleswobth’s pocket-book
Skin Resistance in Vessels.
S = Immersed surface of vessels in square feet.
V = Velocity in knots per hour.
x qx Coefficient for surface.
r = Skin resistance of vessel in lbs.
r = Sæ V3.
a: — -<)07 smooth copper sheets.
= *01 wood planed and painted,
= • 016 ditto sawn.
= ‘014 iron painted.
= ’017 to ’06 foul with barnacles and weed.
Cross-sectional Resistancb to Vessels.
A = Area of largest immersed cross-section in feet.
V = Velocity in knots per hour.
1*= Power required to propel each square foot of a flat-
ended body through the water—in lbs. (See Table
below.)
H = Horse-power required for each square foot of ditto.
K = Coefficient for different water-lines.
R = Resistance due to the sectional area of the ship.
K = A P K.
P-—2-852 V2.
H = -0087587 V3.
Values of K.
For square ends; K = 1
„ wave line 5 to 1; K 3= "11
„ „ 6 „1;K = -Of?
„ „ 7 „ 1; K = -056
„ >, 8 „ 1; K = »043
» „ 9 „ 1; K = • 034
,, ,, 10 „ 1; K = "023
In a ship of tolerably fine lines moving at moderate speed
the whole resistance consists of skin friction, and the cross-
sectional resistance may ba neglected.