214 Ship Design for Efficiency and Economy

Nomenclature

			Recommended
			measuring
Symbol		Title	unit
A		Area in general	m2
A		Rise of floor	m
ABT		Area of transverse cross-section of a bulbous bow	m2
AE		Expanded blade area of a propeller	m2
AL		Lateral-plane area	m2
AM		Midship section area	m2
A0		Disc area of a propeller: D2=4	m2
AP		Aft perpendicular
b		Height of camber	m
B		Width in general	m
BM		Height of transverse metacentre .M/	m
		above centre of buoyancy .B/
BN		Beaufort number	Bft

CCoefficient in general

CA	Correlation allowance
CB	Block coefficient: r=.L B T/
CBD	Block coefficient based on depth
CBA	Block coefficient of aftbody
CBF	Block coefficient of forebody
CDH	Volumetric deckhouse weight
CF	Frictional resistance coefficient	AM=.B T/
CM	Midship section area coefficient:
CM	Factor taking account of the initial costs of the `remaining
	parts' of the propulsion unit
CP	Prismatic coefficient: r=.AM L/
CPA	Prismatic coefficient of the aftbody
CPF	Prismatic coefficient of the forebody
Cs	Reduced thrust loading coefficient
CTh	Thrust loading coefficient
CEM	Concept Exploration Model
CRF	Capital recovery factor	1/yr
Cr	Volume±length coefficient
CWP	Waterplane area coefficient: AWL =.L B/
CWL	Constructed waterline

							Nomenclature 215
d				Cover breadth			m
D				Moulded depth of ship hull			m
D, Dp				Diameter of propeller			m
DA				Nozzle outside diameter			m
DA				Depth corrected for superstructures			m
DI				Nozzle inside diameter			m
e				Dynamic lever as defined by Rahola			m
E				Dynamic stability			Nm, J
F				Freeboard			m
F				Annual operating time			h/yr
Fn				Froude number: V=p
					g L		2
Fo				Upper deck of a deckhouse			m
Fu				Actually built over area of a deckhouse			m2
FP				Forward perpendicular
GDH				Deckhouse mass			kg
GL				Germanischer Lloyd
GM	,	GM	0	Height of metacentre .M/ above centre of gravity .G/			m
h				Water depth			m
h				Lever arm			m
hdb				Height of double bottom			m
i				Rate of interest			1/yr
iE				Half-angle of entrance of waterline			°
iR				Half-angle of run of waterline			°
IT				Transverse moment of inertia of waterplane			m4

JAdvance coefficient

k	Annual payment	MU/yr
k	Form factor addition	MU/yr
K	Individual payment	MU/yr
kf	Costs of one unit of fuel	MU/t
kl	Costs of one unit of lubricating oil	MU/t
kM	Costs of one unit of engine power	MU/kW
kst	Costs of one unit of installed steel	MU/t

KCorrection factor in general

KG				Invested capital	MU
KM				Costs of main engine	MU
KPV				Present value	MU
KB				Height of centre of buoyancy .B/ above keel .K/	m
KM				Height of transverse metacentre .M/ above keel .K/	m
KG		StR		Height of centre of gravity of the steel hull above keel	m
l				Cover length	m
l				Investment life	yr

216 Ship Design for Efficiency and Economy
L	Length in general	m
L0	Wave forming length	m
LB	Length of bulb	m
LD	Length of nozzle	m
LE	Length of entrance	m
Los	Length over surface	m
Lpp	Length between perpendiculars	m
LR	Length of run	m
Lwl	Length of waterline	m
lcb	Distance of centre of buoyancy from midship section	m
MKr	Heeling moment	Nm
MU	Monetary unit	DM, $, etc.

nNumber of decks

n	Rate of revolution	min 1
NPV	Net present value	MU
P	Parallel middle body	m
PB	Brake power	kW
PD	Delivered power	kW
PE	Effective power	kW
PWF	Present worth factor
R	Radius in general	m
RAA	Wind resistance	N
Rn	Reynolds number
RF	Frictional resistance	N
RPV	Viscous pressure resistance	N
RR	Residual resistance	N
RT	Total resistance	N
s	Height of a parabola	mm
sf	Specific fuel consumption	g/(kW h)
sl	Specific lubricant consumption	g/kWh
sv	Forward sheer height	m
sh	Aft sheer height	m
S	Wetted surface	m2

tThrust deduction fraction: .T RT/=T

t	Trim	m
t	Material strength	mm
tD	Nozzle thrust deduction fraction
T	Draught in general	m
T	Propeller thrust	N
Td	Nozzle thrust	N
V	Speed of ship	kn
VA	Advance speed of a propeller	m/s
r	Volume in general	3
		m3
r	Displacement volume of a ship	m3
rA	Superstructure volume	m

		Nomenclature 217
rb	Volume of beam camber	3
		m3
rD	Hull volume to depth, D	m3
rL	Hatchway volume	m3
rs	Volume of sheer	m3
rdb	Volume of double bottom	m3
rDH	deckshouse volume	m3
rLR	Hold volume	m3
rU	Volume below topmost continuous deck	m

wWake fraction: .V VA/=V

wd	Nozzle wake fraction	m3
W	Section modulus
Wdw	Deadweight	t
WAgg	Weight of diesel unit	t
WGetr	Weight of gearbox	t
Wl	Cover weight	t
WM	Weight of propulsion unit	t
Wo	Weight of equipment and outfit	t
WProp	Weight of propeller	t
WR	Weight margin	t
WSt	Weight of steel hull	t
WStAD	Weight of steel for superstructures and deckhouses	t
WStR	Weight of steel hull w/o superstructures	t
WStF	Weight of engine foundation	t
WZ	Weight of cylinder boiler	t
WED	Wake equalizing duct
WL	Waterline
y,Y	Offset in body plan of half width plan

ZNumber of propeller blades

	Nozzle dihedral angle	°
D	Quasi propulsive efficiency: RT V=PD
H	Hull efficiency: .1 t/=.1 w/
o	Propeller efficiency in open water
R	Relative rotative efficiency
	Wavelength	m
	Mass density: m=r	t/m3

Load ratio

1

Displacement mass

t

1Difference (mathematical operator)

Angle of inclination, heel angle

°