Feature 4 | green shiP technology
Optimised hulls lower gas emissions3/2007
Early hull optimisation lowers greenhouse gas emissions
A latest report from Swedish research body research SSPA concludes that
early hull optimisation can provide significant reductions in greenhouse
gas emissions from ships.
S
SPA has conducted a number of
studies of different ship types,
including product carriers, Panamax
and Suezmax tankers, VLCCs, and liquefied
natural gas carriers, with a view to optimising
hull lines to enhance fuel efficiency.
Operational, port, and seaway
requirements and restrictions were used as
Predicted Propulsion
the basis for parameter selection, and main
Power for the Panamax concept
at design draught for a range of
hull dimensions and different hull concepts
different main hull dimensions.
such as twin skeg and single screw were
With consideration given to op-
of most interest in the studies. SSPA has a eration and terminal restrictions,
hull database with ov
M
er 6000 models tested,
optimum main hull dimensions –
agnus Källman,
including over 300 twin skeg hullforms.
with respect to minimum power
project manager at SSPA. He
– can be selected from this type
By using
r
eceived
this dat
his
aba
M.Sc
se, SS
.
P
in
A
Engineer-
says it has
of diagram.
been possibing le Phto ysics perfofrrom m pChalmerarametrs ic hull
optimisatio
Univer
n at a
sity
ve
of
ry
T
e
ec
a
hnolo
rly st
gy
age
in
of the Predicted propulsion power for the Panamax concept at design draught for a range
design proc
Göteborg.
ess. A pr
o
In
ce
1994
dure fo
he
r t
joined
heoretical of different main hull dimensions. With consideration given to operation and terminal
SSPA, where he has worked Verifying tests
calculation of hull resistance and propulsive restrictions, optimum main hull dimensions – with respect to minimum power – can be
Kattegat, Skagerrak, North Sea, English Channel and
with underwater acoustic
power in a s
signatur
eaway as
es
w
,
e
noise
ll as in
contr
calm
ol,
w
and
ater has selected from this type of diagram.
To verify the results of the dimension study one set North Atlantic to the east coast of the US.
been develosystem ped. specifications, and has
of hull main data per concept was selected. From the Not astonishingly the North Sea environmental
Influenc
been
e of
r
esponsible
hull typ
for
e
leading
and hull
selected sets of hull data, one twin skeg and one single conditions when going westward added a higher sea
dimensions
and
such
coor
as
dinating
length, b
ship
eam
de- screw Panamax form was designed and refined by CFD.
power to the ship than the Baltic conditions did. Going
, draught, as in calm water. The main hull dimensions The route used for the Panamax tankers
sign and simulation software Hull models were then built and tests in calm water and west across the Atlantic ocean requires a higher average
block-coeff
pr
ic
ojects
ient,
.
and displacement were –
wa
le
v
n
es
gth
w
, b
ere
eam
car
, dr
r
a
ied
ugh
out
t, blo
in
ck-
the
coeffi
SSP
cie
A
nt
T
,
owing
was f
T
r
ank.
om Ventspils in Latv
po
ia,
w
th
er
rou
because
gh Store
of the dominant SW-NW wind and sea
investigated
T
.
elephone: +46-31 7729036
and displacement – were varied over a wide Baelt in Denmark, Kattegat,
direction
Skagerrak,
where
North
the wave height can build up due to
The studyE -smhaoilw: meda gtnhuast. ktahlelm gaani@n
ascsphaie.sveed range for each concept, while the payload was Sea, English Channel, and North Atlantic to
by choosing the optimal hull type and hull k
Ad
ept c
ded
onstant.
r
Th
esistance
e influence of se
due
a condi
to
tion
wind
the Eas
and
longer fetch. It was found that when going eastward, the
waves
t Coast of the USA.
sea margin was about 1/4 of the magnitude when going
main dimensions that conform to stated and operating environment in choosing hull Not surprisingly, thweestward. North Sea
operational restrictions could equate to a aIn ndaddition propeller to mairesistance n dimensionin s wcalm ith rewaterspect , added enviroresist-nmental conditions when going
significant difference in required propulsive t
ance
o mini
in
mu
a
m
sea
po
wa
wer
y
w
due
as stu
to
die
wa
d.
ves, wind and
we
leewa
stward
y
ad
was
ded a higher sea
Fuel
power t
cost
o the ship
for ship life time
power – typically up to several per cent in a
predicted. Wave data were collected from
than
Global
the Ba
W
ltic
a
v
c
e
onditions did. Going west
seaway, and in some cases, 10% or more. V
Statistics
erifyin
(BMT
g tes
Fluid
ts
Mechanics), which pro
acro
vide
ss the
wa
A
v
tl
e
antic ocean
An
requ
inter
ires a
polation
higher
software program that was developed
BP Shipping Ltd commissioned SSPA to T
data
o veri
f
f
or
y th
a
e
n
re
umber
sults of
of
the
ocean
dimens
areas.
ion stu
Wind
dy, a
resistance
verage pow
coef-
er because o
within
f the d
the
omi
project
nant
will be a helpful tool for comparing dif-
ficients were collected from wind tunnel test data for ferent hull designs and main dimensions with respect to
carry out a study, the ‘BP Hydrodynamic one set of hull main data per concept was SW-NW wind and sea direction where the
tanker hulls at design draught. fuel consumption. The comparison of new building costs
Development Program 2006’, specific to selected. One twin skeg and one single wave height can build up d
of
ue t
diff
o lo
erent
nger fe
designs
tch.
with reliable lifetime fuel cost predic-
Panamax tankers, to establish the trade-off screw Panamax form was designed and It was found that when going eastward, the
between propulsive power and various hull r
Sea
efined
margin
tions will make economic decisions easier. The outcome
by CFD. Hull models were then sea margin was about on
from
e qua
the
rter
study
of the
helps BP to reduce fuel costs during the
parameters. The study includes both single b
The
uilt a
route
nd test
used
s in
f
c
or
alm
the
wa
P
te
anamax
r and wa
tank
ves
ers
m
was
agnitu
from
de when going wesship’twars
d.lifetime.
screw and twin skeg hull designs, where the wVeentspils re carriedin oLatvia,ut in th ethrough SSPA ToStore wing TBaelt ank. in DenmarAn interk,po lation software pMagnus rogram wKällmanas
power demand for a single screw versus a In addition to resistance in calm water, developed within the project that SSPA says
twin skeg vessel is hig
BP
hly dep
Shipping
endent o
Ltd.
n sh
ip added resistance in a seaway due to waves, will be a helpful tool for comparing different
size and resthas ricticommissioned ons in ship draSSPughA t. to wind, and leeway was predicted. Wave data hull designs and main dimensions with
The aim
carr
of
y
th
out
e p
extensive
roject wa
hull
s to
par
inc
a-
lude were collected from Global Wave Statistics respect to fuel consumption. The comparison
environmen
metr
tal an
ic
d
studies
operati
,
o
BP
nal
Hydr
consi
ody-
derations (BMT Fluid Mechanics), which provide of newbuilding costs of different designs with
namic Development Program I
when choo
and
sing
II.
h
The
ull
SSP
typ
A
e
pr
an
oject
d hu
team
ll main wave data for a number of ocean areas. reliable lifetime fuel cost predictions will make
dimensions
consists
with resp
of
ec
exper
t to m
ts
in
within
imum
h
p
y-
ower. Wind resistance coefficients were collected economic decisions easier. The outcome from
Hull resistadrncodynamicse and pro, pprulopulsion,sive pow hull er were from wind tunnel test data for tanker hulls the study will also help BP to reduce fuel costs
calculated f
design
or oper
and
ation
manoeuvr
in a seaw
ing.
ay
F
a
r
s
om
well at design draught. during the ship’s lifetime. NA
left to right are Magnus Käll-
The Naval Ar
man
chitect
(SSPA),
Januar
Daniel
y 2008
Flodén
73
(SSPA), James Collett (BP),
Mikael Grekula (SSPA), Henrik
Andreasson (SSPA), Jonathan
Bailey (BP), Nick Davison
NA Jan -
p73.indd 73
(BP) and Hans Liljenberg
08/01/2008 09:28:10
(SSPA) (missing Peter Trägårdh
(SSPA)).
3
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108