1 Ex. Cal.

Case1 Case1 ks=1.029 m

Case2 Case2 ks=9.408 m
Case3 Case3 ks=191.1 m
Case4 Case4 ks=249.9 m
?

P
0.8 Case5 Case5 ks=286.7 m p

?
10K Q

10KQ 0.6

KT
KT

0.4

0.2

0
0 0.5 1 JS 1.5

Figure 3: Experiment results of fouled propeller performance.

-0.08
Experiment results
Calculation and experiment results
T

Calculation results results by Eq.(5)

Estimating calculltion
? K

Estimat ing calculltion

Estimating results results
by simplified methodEstimating
by Nishikawa method
Estimating
results calculltion
by ITTC 1978results by ITTC 1978
-0.06

Eq.(5) in this paper

-0.04

Simplified
Nishikawamethod
method
(Nishikawa
-0.02
ITTC 1978

0
0 0.002 0.004 0.006 0.008
? K Q

Figure 4: Relation between ? KT and ? KQ.

The proposed method for analysis was applied to training ship FUKAEMARU in
actual service. She is equipped with torque meter as well as thrust meter. A
series of speed tests were carried out in order to investigate the effects of hull
and propeller surface fouling on propulsion performance. The experiment results
and estimation results obtained by the proposed method are shown in Fig.5 and 6.
As seen, it can be said that the estimation results explain very well the
deterioration of propeller performance and hull resistance.
In order to investigate its application for general ships, an analysis of Ab-Log
data of an ocean going vessel was carried out according to this proposed analysis
method. The estimation results of propulsion performance are shown in
Figs.7and 8. Fig.7 shows time history for 6 years, with two dry-dockings.
 0.8 Ex. 1
Open test results by a model propeller at Re=6*10 5 198705 the 1st docking basic line of KT
6
Actual propeller Re=4.9*10 (at 0.7R) 198705 the 1st docking basic line of 10KQ

P
1month after docking POT Results

?
6months after docking Ex. Estimating cal.
P

199907 10months after docking

12months after docking 0.8
?

199908 11months after docking

0.6 Cal.
ks=50 m ? p & Prop. cleared
ks=150 m 199912 2months after docking
ks=250 m
? p
10KQ

ks=350 m
10KQ
0.6

10KQ
0.4
10K Q
0.4
KT

KT
0.2
KT 0.2 KT

0 0
0.3 0.4 0.5 0.6 0.2 0.4 f = 20 0.6 JS 0.8
JS

Figure 5: Propeller performance of FUKAEMARU in service.

100
Ex. Estimating cal.
199907 10months after docking
199908 11months after docking
80 and Prop. cleared
199912 2months after docking
Rt(KN)

60

40

20

0
8 9 10 11 12 13 14
f = 20 Vs(knot)

Figure 6: Hull resistance of FUKAEMARU in service.

The propeller performance tends to deteriorate reasonably as the time passes

from the previous docking and tends to recover due to cleaning works at dry-
dock. But, it is difficult to see a certain trend of changes in the hull resistance
performance. Fig.8 show all the data of propeller open characteristics and the
hull resistance coefficient respectively during first service term i.e. in clean
condition between the start of service and the first docking. The estimation
results spread on both the figures. However, there is a specific distribution
pattern i.e. the advanced ratio especially extends to a wide value although the
measured torque does not change widely. The value of the data of ship speed is
wondered about the accuracy. If the ship speeds data would include a certain
error, the analysis results are affected as shown in Fig.9. An error in ship speed
data has a great influence on the estimation of results, especially of hull
resistance, because the present thrust performance is estimated from the present
torque coefficient and the performance of clean propeller, and the hull resistance
is obtained from the propeller thrust. It should be stressed that a ship speed
measurement device is not generally disputable, however it is pointed out that
there is an ample scope for improvement of recording method of ship speed in a
 0.15
0.10
KQ / KQ0
??KQ/KQ0

0.05
0.00
-0.05
-0.10
1st Dock in 2nd Dock in
Oct-97 Oct-98 Oct-99 Sep-00 Sep-01 Sep-02 Sep-03

0.05
? KT?KT/KT0

0.00
/ KT0

-0.05

-0.10
Oct-97 Oct-98 Oct-99 Sep-00 Sep-01 Sep-02 Sep-03

0.10
0.05
/ ?P 0P0

0.00
??? ?P /P ?

-0.05
-0.10
-0.15
Oct-97 Oct-98 Oct-99 Sep-00 Sep-01 Sep-02 Sep-03
1st Dock in 2nd Dock in
0.50
0.40
? C T / C T0

0.30
?CT/CT0

0.20
0.10
0.00
-0.10
Oct-97 1st YearOct-98 2nd YearOct-99 3rd YearSep-00 4th YearSep-01 5th YearSep-02 6th YearSep-03

Figure 7: Time history of propulsion performance of an ocean going vessel.

0.6

0.5
0.020
, 10KQ

0.4
Q

0.018
10K
? TP, , KT

0.016
0.3
? P, K

CCTT

0.014

0.2
0.012

0.010
0.1
0.14 0.15 0.16 0.17 Fr 0.18
0.30 0.35 0.40 0.45 0.50
J
J
Fr
Fr

Figure 8: Propeller performance and hull resistance

coefficient of an ocean going vessel.