A study on weather routing of high speed ships

A Study on Weather

Routing of High Speed Ship

H.

Hagiwara,

Tokyo

University

of Mercantile

Marine,

H. Fukuda,

Graduate

School,

Tokyo

University

of

Mercantile

Marine,

K. Sugai,

The

Shipbuilding

Research

Association

of Japan, Y.

Kusaka,

Akishima

Laboratories

(Mitsui Zosen) Inc.

ABSTRACT

In this study, speed performance and operation limit of a Japanese high speed ship “TSL-A” (127 m LOA) in waves were estimated from the sea trial data of the model ship of TSL-A (70 m LOA). Using the wave data produced by a fine-mesh wave forecast model and the statistical ocean current data, comprehensive weather routing simulations of the TSL-A were performed. The isochrone method was adopted to determine the minimum time route. In the results of the simulations, the effectiveness of weather routing for the high speed ship was jidly demonstrated.

1.

INTRODUCTION

Ship weather routing is defined as a procedure to determine an optimum route based on the forecasted environments and the ship’s speed and seakeeping performance for a particular transit. In winter season,

ship weather routing is indispensable for the ocean-crossing ships, and many vessels such as container ships, pure car carriers, ore carriers, etc. have been using the weather routing services.

Concerning the high speed ships, however, since the number of these ships is not so large and their operation is considerably different from that of the conventional ships, the use of weather routing service has not yet been promoted. In this study, the Techno Super Liner (TSL-A) (127m LOA) [1] which had been developed in Japan was adopted as an example of the high speed ships.

First, the speed performance and operation limit of the TSL-A in waves were estimated based on the sea trial data of “Hisho”, the model ship of TSL-A (70m LOA). The operation limits were set for the head and bow waves in order to avoid the wet deck slamming. Next, the wave data and the ocean current data were prepared for the simulations. The wave data were produced by a fine-mesh wave forecast model covering the Japan Sea, the East China Sea and Japanese coastal waters with grid intervals of 2 minutes.

Using the above mentioned speed performance

data as well as wave and ocean current data, comprehensive weather routing simulations of the TSL-A were carried out to investigate the effectiveness of weather routing for the high speed ship.

2. SPEED PERFORMANCE OF HIGH SPEED SHIP IN WAVES

The speed performance of the TSL-A in waves was estimated from the sea trial data of “Hisho’’(Photo 1), the model ship of TSL-A. Principal particulars of “Hisho” and the TSL-A are shown in Table 1.

The speed performance data of “Hisho” in light condition obtained from the sea trial are shown in Fig. 1.

Photo 1 Model ship of TSL-A “Hisho”

219

Table 1 Principal particulars of “Hisho” and the TSL

TSL - A Length over all 70,0 m 127.0 m Breadth molded 18.6 m 27.2 m Depth molded 7,5 m 11.Om Draft

““””””’”’””””””””’”’””’’’””:’”””Off cushion “’”””””””””””’””’’3;s”rn”””””””““”’””””””””””’’””5:o”rn”””””” ““’””’”’’”’’’”’”””””””””””’:’”””On cushion ““’”””””””’”””””””1.I’%”””’”””““”””’”’’’”””””””””l:4urn””””””

Speed 50,0knots 50.0 knots Cruising range 500 miles over 500 miles Dead weizht I 200 tons ltXIO tons

Structure f..ongitudinal frame Longitudinal frame

Hull material Arrtieorrosive Anticorrosive aluminum alloy aluminum alloy Seals_{. . . ... ... ...} 1 Bow Fullfinger 1 Full fm.$er .... .... . .... ... . .. ... .. . . ... . . . .. .

Stern Robe Robe

100 70 I *--WAVE DIRECTION + 0“ *45” -X- 90” + 135”

II

, ----

i

11

-s-180”

I

60 1 I o 0.5 1 1.5 2 2.5 3 3.5 4

WAVE HEIGHT (METERS)

Fig, 1 Speed performance data of “Hisho” (light condition) obtained from the sea trial

Using the data shown in Fig.1, speed of “Hisho” in waves was represented by the regression curve for each wave direction from the bow. Then, to convert the speed of “Hisho” into that of TSL-A, the wave heights attached to the horizontal axis in Fig.1 were multiplied by 127/70 (ratio of the length of TSL-A to that of “Hisho”) and the speed in calm water was set to 50 knots. The speed performance curves of the TSL-A (light condition) in waves are shown in Fig.2. In Fig.2, speed curves for the wave direction from the bow of O,

30, 45, 60, 75, 90 and 180 degrees are drawn when the engine power is 84,000 PS, and speed curves for the head waves are also drawn when the engine power is 74,000,64,000 and 54,000 PS. 50 25 84000PS 1 , %e60r% —:+ ‘.. ____ —.* _+— —. .+____ wAVE OIRECTION * 45” + 60” “., ‘.. + 75” + 90” — L ... . V 3rY 4V + 1s0” 1 20 1’ 0 Fig.2 1 2 3 4 5 6 7

WAVE HEIGHT (METERS)

Speed performance curves of the TSL-A (light condition) in waves

The operation limit of the TSL-A in heavy weather was estimated according to a hearing to the captain of “Hisho”. (“Hisho” was converted into a high-speed ferry renamed “Kibo” after completing various sea trials and has been plying between two Japanese ports, Shimizu and Shimoda.) The wet deck slamming is considered to be a main cause that the TSL-A has to reduce its engine power in rough seas. Although the wet deck slamming was not observed during all the sea trials of “Hisho” including maximum wave height of 4.5 meters, it is necessary to reduce the engine power of “Kibo” in head waves higher than about 3 meters in order to avoid the danger of wet deck slamming and to retain the safety and comfort of the passengers.

Concerning the TSL-A, maximum safe speed in head waves was assumed to be 42.1 knots for the wave height of 4 meters and 30.0 knots for the wave height of 5 meters. In Fig.2, the dotted line connecting these two points represents the operation limit speed for head waves. In bow waves (i.e. wave direction from the bow of 45 degrees), maximum safe speed was assumed to be 41.7 knots for the wave height of 5 meters. In Fig.2, the dotted line passing this point represents the operation limit speed for bow waves. The inclination of the line is equal to that of the operation limit speed for head waves.

The longitudinal motions of TSL-A due to waves and the danger of wet deck slamming decrease rapidly as the wave direction from the bow increases. So assuming that interval between the line of operation limit speed for an arbitrary wave direction and that for

head waves is proportional to the square of the wave direction, operation limit speed Vli~it of the TSL-A was calculated by the following formula.

Vli~it = _12.349h + (91.745 + 0.005908d2) (1)

where h : significant wave height (meter) d : wave direction from bow (degree) In the simulations, when the speed of TSL-A exceeds the operation limit speed, the engine power was reduced by 1,000 PS until the speed became less than the operation limit speed.

Based on the speed performance data of “Hisho” obtained from the sea trial in full load condition, speed performance curves of the TSL-A in waves were also determined. The speed performance curves of the TSL-A in full load condition are shown in Fig.3. From Fig.3, it is found that variation of the speed for the change of wave direction is smaller than that in light condition. The operation limit speeds were assumed to be the same as those in light condition.

55 50 25 20 84000PS 1 <) 740QOPS -E400# ----, 0 Fig.3 1 2 3 4 5 6 7

WAVE HEIGHT (METERS)

Speed performance curves of the TSL-A (full load condition) in waves

3. ENVIRONMENTAL

DATA USED FOR

WEATHER

ROUTING OF HIGH SPEED SHIP

The TSL-A has been planned to be put into service in the Japan Sea, the East China Sea, Japanese coastal waters, etc.. To perform the effective weather routing of the TSL-A in these areas, it is necessary to forecast the environmental conditions up to about 24 hours ahead with short forecast intervals and high density forecast grids. The wave forecast data and statistical ocean current data were used for the simulations of this study.

The wave forecast data covering the above areas in January 1997 were obtained from Japan Weather

Association and used for the simulations. Significant wave height, primary wave direction and average wave period are given on each forecast grid point. The grid intervals are 2 minutes in both latitudinal and longitudinal directions. The actual (analysis) wave data are given at 00 and 12GMT and the 6-hour forecast wave data are given at 06 and 18GMT. (These wave data were specially prepared for this study. In actual operations, the wave forecast data are given up to 72 hours ahead at 00 and 12 GMT with forecast intervals of 6 hours.)

In the simulations, wave data were extracted from the original data base with grid intervals of 4 minutes to

save

the memory space. The wave data at the ship’s position at an arbitrary time were calculated by using spatial and time interpolations. As an example of the wave data, a wave chart at 0900JST on January 2, 1997 is shown in Fig.4 with grid intervals of 30 minutes. In Fig.4, direction and size of each arrow represent the primary wave direction and the significant wave height, respectively. Since the depression passed through the northern part of the Japan Sea on January 2, high waves developed from the western part of the Japan Sea,

40N

30N

l~OE liOE

WAVE HEIGHT -2 M+4M*6M

Fig.4 Wave chart at 0900JST on January 2, 1997

Concerning the ocean current data, statistical data covering 45 years (1953-1997) were obtained from Japan Oceanographic Data Center. In these data, monthly mean ocean current speed and direction are given in each 1x1 degree mesh in each year. Since the variation of monthly mean ocean current conditions was not so large, the data were averaged over 45 years

221

in each mesh and the 45-year mean ocean current data were produced to be used in the simulations. A 45-year

mean ocean current chart is shown in Fig.5. In Fig.5,

we can see that the strong Japan Current (Kuroshio) streams along the south coast of Japan. In the simulations, the ocean current data at an arbitrary position were calculated by using spatial interpolation.

:URRENT CHART

/f\l/<f+\\-/Nl

-,, , .

;L3Y’Y

f——

1“

L“

E _&3 —A\’1l’l ’(/ ‘Y l$OE 140E —0.4 +0.8 +1.2 +1.6 KNOTS ON ON

Fig.5 45-year mean ocean current chart

4.OPTIMUM ROUTE SIMULATIONS OF

HIGH SPEED SHIP

In this study, regarding the minimum time route (MTR) as the optimum route, isochrone method was used for the route optimization [2]. The isochrone method determines the MTR by repeatedly computing an isochrone (or time front) which is defined as an outer boundary of the attainable region from the departure point after a certain time. In the simulations, the speed of TSL-A was calculated at intervals of 15 minutes and the isochrone was computed every 1 hour. The heading of TSL-A was searched at intervals of 3 degrees and the resolution of the isochrone (i.e. an average distance between two successive points which constitute an isochrone) was set to 3 nautical miles.

To investigate the advantage of the MTR, passage time on the great circle route (GCR) was also computed. The TSL-A was navigated on the GCR by calculating the speed and initial course of the GCR from the ship’s position to the destination at intervals of 15 minutes.

4.1 Change of Minimum Time Route Due to

Different Setting of Operation

Limit

In order to investigate how much a MTR depends

on the operation limit mentioned in Chapter 2, the

minimum time route simulations of TSL-A in light

condition were performed based on the following 3

kinds of operation limits. (The engine power was set to

84,000 PS with which the TSL-A could run at 50 knots

in calm water.)

- Operation limit (1) : The operation limit

speed lines shown in Fig.2 were shifted to the left by 1 meter, i.e. in head waves, the TSL-A reaches operation limit speed at wave height of 3 meters and the engine power has to be reduced for higher waves.

- Operation limit (2) : The operation limit speed lines shown in Fig.2 were used without change, i.e. in head waves, the TSL-A reaches operation limit speed at wave height of 4 meters and the engine power has to be reduced for higher waves.

- Operation limit (3) : The operation limit speed lines shown in Fig.2 were shifted to the right by 1 meter, i.e. in head waves, the TSL-A reaches operation limit speed at wave height of 5 meters and the engine power has to be reduced for higher waves.

For the voyage departing from Tsugaru Strait for Busan at 0600JST on January 2, 1997, minimum time route simulations were carried out. At present, although a cruising range of the TSL-A is about 500 nautical miles, it was assumed that the TSL-A could sail for a longer distance. (The great circle distance between Tsugaru Strait and Busan is 634 nautical miles.)

The result of the simulation based on the operation limit (1) is shown in Fig,6. In Fig.6, both the MTR and the GCR are shown. The arrows attached to each route indicate the wave directions and heights at intervals of 1 hour; the positions of arrow heads represent the ship’s positions. The isochrones are drawn every 1 hour from the departure time. In this voyage, the speed of TSL-A largely decreased on the GCR because of high head waves. The MTR passed the north side of the GCR largely detouring the area of high head waves, On the MTR, the TSL-A navigated westward while receiving southerly waves and changed the course southward when wave direction changed to the west in order to avoid high head waves (i.e. in order to avoid the reduction of engine power owing to operation limit). The passage time on the MTR was 4.1 hours shorter than that on the GCR.

The result of the simulation based on the operation limit (2) is shown in Fig.7. Also in this case, the MTR passed the north side of the GCR but the deviation from the GCR was not so large compared with the MTR in Fig.6. Compared with tie GCR, the passage time was

shortened by 1.6 hours on the MTR.

The result of the simulation based on the operation limit (3) is shown in Fig.8. Since the TSL-A could run with large engine power in considerably high head waves under this operation limit, the deviation of MTR from the GCR was small. Compared with the GCR, the passage time was shortened only 0.4 hours on the MTR.

The result of the simulation without the operation limit is shown in Fig.9. The deviation of MTR from the GCR was small and the passage time on the MTR was

40N

30N

130E 140E

WAVE HEIGHT -2r”l —4P’ —6M

Fig.6 Minimum time route based on operation limit (1)

I I

130E 140E

WAVE HEIGHT ‘2 M—4M —6M

40N

30N

only 0.1 hours shorter than that on the GCR.

Time histories of ship’s speed and engine power on the MTR and the GCR during the above simulations are shown in Fig.10. In Fig. 10, black triangles and white circles represent the values on the GCR and on the MTR, respectively. On the GCR, since the TSL-A sailed receiving high head waves, the engine power was largely reduced not to exceed the operation limit. Amount of reduction of the engine power was large in order of the operation limit (l), (2) and (3).

~

WAVE HEIGHT --2/4 —4M —6M

—

-40P

3oh

Fig.8 Minimum time route based on operation limit (3)

I I 130E 140E WAVE HEIGHT +2M —4M —6M 40N 30N ,.

Fig.7 Minimum time route based on operation limit (2) Fig.9 Minimum time route without operation limit

On the other hand, on the MTR, reduction of the engine power was small for all operation limits, and it is found that the TSL-A could sail very fast compared with the GCR. 50 40 ~ 50 z 40 n ~ 30 LLl OPERATION LIMIT(2) L 20 681012141618 202224 80 4 ~ 60 0 x 40 OPERATION LIMIT(1) m ?0 in -- =,-(3 z 80 Lu I OPERATION LIMIT(3) ] 60 I 681012141618 202224 TIME (JST JAN.2 1997)

Fig. 10 Time histories of ship’s speed and engine power on the MTR and the GCR

From these simulations, it can be seen that a track and passage time of the MTR of TSL-A largely change depending on the setting of operation limit. Hereafter, operation limit (2) described by formula (1) is used in

this study.

4.2

Change of Minimum Time Route Due to

Difference of Departure

Time

Minimum time route simulations of the TSL-A in

light condition departing from Tsugaru Strait

for Busan at OOOOJST and 0300JST on January 2, 1997 were carried out. The results are shown in Fig.11 (departure: OOOOJST) and Fig.12 (departure: 0300JST). In the

voyage departing at OOOOJST,since high wave area existed in the western part of the Japan Sea and was moving eastward, the MTR largely detoured to the south of the GCR so as to pass the front of moving high

wave area, In the voyage departing at 0300JST,

however, since high wave area moved to the eastern part of the Japan Sea, the MTR detoured to the north of the GCR in order to pass the rear of moving high wave

-u .... J GCR: 17.60H 36.08KT I .0 I I 130E 140E WAVE HEIGHT +2M —4M —6M 401 3ot

Fig.11 Minimum time route of TSL-A (light condition) departing at OOOOJSTon January 2, 1997

40N -&# MTR: 15.58H 42.59KT .. ) GCR: -0 17.87H 35,54KT I I 30N 130E 140E

WAVE HEIGHT *2PI —-4M —6M

Fig.12 Minimum time route of TSL-A (light condition) departing at 0300JST on January 2, 1997

,.

224

area. From these simulations, it is found that the MTR largely changed when the departure time was delayed by only 3 hours.

On January 1 and 2, the departure time was changed at intervals of 3 hours in order to investigate the variations of the MTR. The MTRs departing from Tsugaru Strait for Busan at 12, 15, 18, 21JST on January 1 and 00, 03, 06, 09, 12JST on January 2 are shown in Fig.13. From Fig.13, it is found that for the voyages departing at 12 and 15JST on January 1, the MTRs (Rl, R2) almost coincide with the GCR. For the voyages departing at 18 and 21JST on January 1 and 00JST on January 2, the MTRs (R3, R4, R5) largely detoured to the south of the GCR so as to pass the front of high wave area which existed in the western part of the Japan Sea and was moving eastward, For the voyages departing at 03 and 06JST on January 2, the MTRs (R6, R7) largely detoured to the north of the GCR in order to pass the rear of high wave area which reached the eastern part of the Japan Sea. For the voyages departing at 09 and 12JST on January 2, since high wave area was disappearing, detour of the MTRs became small. From these simulations, it can be seen that the MTR of the TSL-A varies largely according to a change of the departure time when high wave area is approaching the GCR.

I ~>l’y

----#wiliil

Fig, 13 Minimum time routes departing from Tsugaru Strait for Busan at intervals of 3 hours

The MTR of TSL-A in light condition changed from the southern route to the northern route for the voyage departing at 03JST on January 2. In full load

condition, however, the MTR of TSL-A for that voyage was still southern route as shown in Fig. 14. The reason of this result is that since the speed of TSL-A in full load condition is not sensitive to the wave direction, the speed reduction became large in the north side of the GCR even if the TSL-A avoided the area of high head waves as shown in Fig.12.. For the voyage departing at 06JST on January 2, the MTR of TSL-A in full load condition changed to the northern route.

l~OE 140E

WAVE HEIGHT +2M —4M —6M

Fig.14 Minimum time route of TSL-A (full load condition) departing at 0300JST on January 2, 1997

4.3 Change of Minimum Time Route Due to

Difference of Arrival Time

Next, by changing

the specified

arrival

time,

changes of the MTR and fuel consumption

were

investigated.

In the simulations, setting the engine

power to a proper (arbitrary) value, the MTR was

calculated

using the isochrone method. During the voyage, the engine power was kept constant except for the reduction not to exceed the operation limit speed. If the TSL-A arrived at the destination before specified arrival time, the engine power was reduced, and vice versa. Then using the adjusted engine power, the MTR was calculated again. This procedure was repeated until the difference between arrival time on the MTR and specified arrival time became less than 1 minute.

On the voyage departing from Tsugaru Strait for Busan at 00JST on January 2, 1997, the MTR of TSL-A in light condition with engine power of 84,000 PS is shown in Fig.15 as “MTR”. In Fig.15, the MTRs for which specified arrival time was delayed by 30, 60, 90

225

and 120 minutes from the arrival time of the “MTR’ are shown as RI, R2, R3 and R4, respectively. In addition, the MTR having specified arrival time equal to the arrival time of the GCR is shown as R5.

The “MTR’ for engine power of 84,000 PS and the R1 detoured to the south of the GCR to pass the front of moving high wave area. On the other hand, for the R2, R3, R4 and R5, high wave area moved to the eastern part of the Japan Sea during the voyage because of a slow ship’s speed. Thus these routes detoured to the north of the GCR to pass the rear of high wave area,

u

}4[

r

PASSAGE TIME MTR: 15.35 H RI :15,87 H R2 :16,38 H R3 :16,88 H R4 :17.36 H .00 ~ I I ‘ 30 130E 140E

Fig.15 Minimum time routes reaching Busan at various specified arrival times

In Fig, 16, the relations between fuel consumption

and passage time on the “MTR and Rl, R2, R3~ R4, R5 are shown. For these calculations, main engines were assumed to be gas turbines and their specific fuel consumption was assumed to be 160 g/(PS hour). From Fig.16, it is found that the fuel consumption decreases as the passage time increases because less engine power was necessary for longer specified passage time. It can be seen that the fuel consumption on the R2 is considerably smaller than that on the R1. This is because the distance run on the R2 which passed the north side of the GCR was considerably shorter than that on the R1 which passed the south side of the GCR.

As can be seen from these simulations, when the arrival time is specified and the high speed ship has sufficiently strong engine power to reach the destination by that time, it is possible to save the fuel by sailing on the MTR with reduced engine power. On the

voyage departing at 00JST on January 2, the passage time and fuel consumption of the TSL-A which sailed on the GCR with engine power of 84,000 PS were 17 hours 35 minutes and 191.1 tons, respectively. The fuel consumption of the TSL-A which sailed on the MTR (R5 in Fig.15 and Fig.16) with reduced engine power so as to reach the destination taking the same passage time as on the GCR was 183.8 tons. Thus compared with the GCR, fuel was saved by 7,3 tons (3.8Yo) on the MTR. 210 ~ 205 z g 200 z o F g 195 3 03 z g 190 -1 u ~ 185 180 15 16 17 18

PASSAGE TIME (HOURS)

Fig.16 Fuel consumption on the minimum time routes for various specified passage times

4.4 Minimum Time Routes in the Japan Sea and

Japanese coastal waters in January

1997

In addition to the route between Tsugaru Strait and

Busan, minimum time route simulations of the TSL-A

in light and full load condition were performed for the

routes between Niigata and Vladivostok, Kanmon Strait

and Vladivostok, Kashima and Kushiro, Tokyo and

Miyazaki. For the voyages departing from each port at

09JST and 21JST every day during the period from

January 1 to January 27, all the MTRs are shown in

Fig.17(a) and Fig.17(b) (light condition) and Fig.18(a)

and Fig. 18(b) (full load condition).

In these figures, the arrows indicate the navigating directions. As shown in Fig.4, since the wave data are not available in the vicinity of Vladivostok, the points on which the rhumb lines from Niigata and Kanmon Strait to Vladivostok cross the boundary of wave data were assumed to be Vladivostok.

For the voyages from Niigata to Vladivostok and from Kanmon Strait to Vladivostok (Fig.17(b), Fig.18(b)), since the northwesterly waves often developed, the TSL-A took large detours to avoid high head waves in which the engine power had to be

reduced because of the operation limit. On the other hand, for the voyages from Vladivostok to Niigata and from Vladivostok to Kanmon Strait (Fig.17(a), Fig. 18(a)), since the TSL-A received the following waves in most of the voyages, the MTRs almost

coincide with the GCRS,

Fig,17(a) All minimum time routes of TSL-A (light condition) departing at 0900 and 21 OOJST every day (January 1-27, 1997)

Fig.17(b) All minimum time routes of TSL-A (light condition) departing at 0900 and 21 OOJST every day (January 1-27, 1997)

For the voyages from Kashima to Kushiro in light condition (Fig.17(b)), although most of the MTRs were close to the GCR, one MTR largely detoured to the east of the GCR. This is because in this voyage, the TSL-A could avoid high head waves which existed in the vicinity of Japanese coast by largely detouring to the

,“&,)ilTAzAKI TIME ROUTES

....

.,l) (J AN.. 1-27,1997)

-401

-301

l~OE 140E

Fig.18(a) All minimum time routes of TSL-A (full load condition) departing at 0900 and 21 OOJST

every

day (January 1-27, 1997)

I I

130E 140E

40P

30!

Fig.18(b) All minimum time routes of TSL-A (full load condition) departing at 0900 and 2 100JST every day (January 1-27, 1997)

east of the GCR.

For the voyages of the TSLA in light condition departing at 09JST and 21JST every day from January 1 to January 27, 1997, changes of the passage times on the MTR and the GCR are shown in Fig.19(a) and Fig. 19(b). In Fig.19, white circles and black triangles represent the passage times on the MTR and the GCR, respective] y. From Fig. 19, it can be seen that although the difference between passage time on the MTR and passage time on the GCR was small for most of the voyages, it became considerably large for some voyages in which the TSL-A received high head waves on the GCR. The maximum time saving was 2.2 hours on the route from Tsugaru Strait to Busan, 2.1 hours on the route from Niigata to Vladivostok and 2.8 hours on the route from Kashima to Kushiro, which verified the effectiveness of weather routing.

For the 54 voyages departing at 09JST and 21JST every day from January 1 to January 27, 1997, the mean value (MEAN) and standard deviation (S. D.) of the passage times on the MTRs and the GCRS are shown in Table 2(a) and Table 2(b) (light condition) and Table 3(a) and Table 3(b) (full load condition). For all the routes, the standard deviations of passage times on the MTRs were smaller than those on the GCRS. Therefore

18 16 14 12 12 10 8 6 13 11 9 14 12 10 8 10 8

TSUGARU KAIKYO + BUSAN

4

~A4 _{..*.. GCR uMTR}

VLADIVOSTOK + NIIGATA

1 !

1---

I

VLADIVOSTOK ~ KANMON KAIKYO

I 1 KUSHIRO + KASHIMA

1

TOKYO ~ MIYAZAKI 1 3 5 79111315171921232527 DATE OF DEPARTURE

(0900JsT AND 21 OOJST JANUARY 1997)

Changes of passage times of TSL-A (light condition) on the minimum time route and the great circle route

18 16 14 12 12 10 ~ ₈ s g6 % ‘3 F ,1 U u <9 (n (n u c1 14 12 10 8 10 8

BUSAN- TSUGARU KAIKYO

1---- ~ &GCR -o- MTR-1 1

1 I

NIIGATA + VLADIVOSTOK

I * I

A :,

KANMON KAIKYO + VLADIVOSTOK

KASHIMA + KUSHIRO 4 + ———.—————————-_{,, ;,} MIYAZAKI + TOKYO 1 3 5 7 9111315171921232527 DATE OF DEPARTURE (0900JST AND 2 100JST JANUARY 1997)

Fig.19(b) Changes of passage times of TSL-A (light condition) on the minimum time route and the great circle route

Table 2(a) Mean and standard deviation of passage times of TSL-A (light condition) for 54 voyages

> ~JSAN 13.61 H 0.54 H ADIVOSTOCK --- NIIGATA 7.36 H 017H ITOCK ,.-,.,.!ON KAIKYO 9.55 H 0.21 H KUSHIRO . . . . . . 931 H 0.13 H TSUGARU KAIKYC - !=!,,! VL/ VLAOIVOS - ./ .,,,”, - FwN7rl,hm, 1 TOKYO - .,, v.h, r.lc 9.56 H I 0.21 H

=l=H

13.70 H O.I35 H 2.21 H 7.36 H 0.17 H 0.01 H 955 Ii 0.21 H 0.03 H 9.34 H 0.15 H 0.09 H -—- — _—

-Table 2(b) Mean and standard deviation of passage times of TSL-A (light condition) for 54 voyages

MINIMUM TIME ROUTE GREAT CIRCLE ROUTE o~R;:;E

MEAN SD. MEAN S.D (GCR-MTR) BUSAN 13.48 H 0,39 H 13.52 H 0.51 H 1,40 H - TSUGARU KAIKYO NIIGATA - VLAOIVOSTOCK 7.68 H 0.51 H 7.81 H 0.88 H 2.13 H KANMON KAIKYO - VLAOIVOSTOCK 9.84 H 0.44 H 9.91 H 0.60 H 1.02 H KASHIMA - KUSHIRO 9.43 H 0.24 H 9.57 H 0.70 H 2.81 H MIYAZAKI _{9.31 H 0.12 H} --- ---- TOKYO

228

.,,.,... .

Table 3(a) Mean and standard deviation of passage times of TSL-A (full load condition) for 54 voyages

TSUGAR( >.,,., -VI “1 . .

a

u

W+in

1u - BUSAN ~LADIVOSTOCK - NIIGATA ‘LAUIVOSTOCK - KANMON KAIKYO KUSHIRO + KASHIMA TOKYO - MIYAZAKI 14.52H 0.51 H 14,61 H 0,77 H 1.99 H 7.92 H 0.22 H 7.92 H 0.22 H 0.01 H 10.27 H 0.27 H 10.27 H 0.27 H 0.01 H 9.96 H 0.13 H 9.99 H 0.16 H 0,13 H 10.24 H 0.17 H -—- -—

-—-Table 3(b) Mean and standard deviation of passage times of TSL-A (full load condition) for 54 voyages

MINIMUM TIME ROUTE GREAT CIRCLE ROUTE J’#&J&

MEAN S,D MEAN S.o (GCR-MTR)

BUSAN

14.38 H 0.43 H 14,41 H

- TSUGARU KAIKYO 0.51 H 1.1OH

NIIGATA - VLAOIVOSTOCK 8.09 H 0.46 H 8.19 H 0.80 H 2.01 H KANMON KAIKYO + VLAOIVOSTOCK 10.37 H 0.37 H 10.42 H 0.50 H 0.94 H KASHIMA -- KUSHIRO 10.04 H 0.19 H 10,16H 0.63 H 2.77 H MIYAZAKI - TOKYO 9.93 H 0.14 H --- —- ___

it can be seen that ship weather routing not only could shorten the passage time but also could improve the punctualness of operation. For the route between Tokyo and Miyazaki, although a variation of the MTRs was small as shown in Fig.17 and Fig. 18, the mean value of passage times on the MTRs from Miyazaki to Tokyo was 16 (19) minutes shorter in light (full load) condition than that from Tokyo to Miyazaki because of the strong Japan Current (Kuroshio).

5. CONCLUSIONS

In this study, the speed performance and operation limit of the high speed ship “TSL-A” in waves were estimated. Then the wave data produced by a fine-mesh wave forecast model and the ocean current data were prepared for the simulations. Using these speed performance data as well as wave and ocean current data, comprehensive weather routing simulations of the TSL-A were performed to investigate the effectiveness of weather routing for the high speed ship. The main results of simulations are as follows.

(1) The minimum time route of high speed ship is largely affected by the setting of operation limit in calculating ship’s speed in waves. The minimum time route detours the area of high head waves in which the engine power has to be reduced not to exceed the operation limit.

(2) Ship weather routing is very effective also for the

high speed ship if there is wide navigable area on both sides of the great circle route to avoid adverse wave conditions.

(3) In some wave conditions, the minimum time route

of high speed ship becomes very sensitive to the

departure time. This is because the minimum time

route changes from the route passing the front of approaching high wave area to the route passing the rear of that area.

(4) In some wave conditions, the minimum time route of high speed ship is considerably affected by loading condition.

(5) When the arrival time is specified and the high speed ship has sufficiently strong engine power, it is possible to save the fuel by sailing on the minimum time route with reduced engine power.

(6) Ship weather routing not only can shorten the passage time but also can improve the punctualness of operation of the high speed ship.

(7) The optimum route simulations can be used as a

powerful tool to determine the speed and seakeeping performance of the high speed ship to be put into service between the given ports. That is, by performing simulations for a long period with various speed performances and operation limits in waves, it is possible to determine the required performance of high speed ship which can sail between the given ports within the planned passage time.

For further development of this study, the speed performance and operation limit of the high speed ship in waves will be theoretically predicted, and the actual operational conditions of the high speed ship will be investigated through the actual voyage data. In addition, since a period of the wave data used for the simulations was only one month, more wave data covering all seasons will be obtained to carry out

comprehensive simulations for verifying the effectiveness of weather routing throughout the year.

References

[1] TSL Technical Research Association, “Present State of Research and Development of the Techno Super Liner”, Bulletin of Society of Naval Architects of Japan ‘TECHNO MARINE’, VO1.785, November 1994, pp.830-853

[2] Weather Routing Research Group, “Weather Routing – Optimum Routing Based on Weather Information –“, Seizando Publishing Corporation, April 1992, pp.250-259

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