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Complex Ship Operation Laboratory

Subject: Optimizing Performance of Ship and Machinery

Task: Bunker Planning

Preparation

Review the dependencies between ship speed, engine break power and fuel consumption

Scenario

2.127 TEU Container Ship (see the ship and engine data below) is preparing for a voyage of 2.220 nm

sea passage distance. Previous voyage was over a distance of 1.404 nm and the average ship speed

at sea passage was 19,5 kn. The new voyage shall be executed at the more economical speed of

18,5 kn.

For the voyage preparation, the total reserve of fuel oil in the tanks (HFO and MDO) has to be

checked and the fuel oil consumption for the planned voyage has to be estimated. If the reserve is

considered to be too low for the voyage, a bunker order has to be prepared.

The technical management has informed, that the bunker fuel in the port of destination is

considerably cheaper than in the departure port were the ship is loading now. The Chief Engineer has

therefore be advised, for the case that bunkering already now is necessary, to order only the

minimum required amount for a safe arrival.

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Task

I. Conduct a bunker planning for the intended voyage

(1) Check the total fuel reserves of HFO and MDO on board (see Annex 2).

(2) From all available data (see above and Annexes 1 and 3), estimate the fuel oil demand (HFO

and MDO) for the intended voyage.

(3) If bunkering before departure is required, how many tons of HFO and MDO shall be ordered?

Assumptions:

1.

It is assumed that both voyages, the previous and the planned next are conducted under

nearly the same conditions, that means both voyages are conducted under nearly the same

-

Loading conditions (draft and trim)

- Weather conditions (average wind state, sea state and tidal current)

- Technical conditions of hull, propeller and main engine

2. During manoeuvring the main engine is fuelled with MDO, at an average consumption of 600

kg/h. Total manoeuvring time (before and after the sea passage) is assumed 8 hours.

II. Variations of the bunker planning task

(1)

What if we dont have previousperformance measurements available such as in Annex 3

Table 2? How can we approximately get a suitable estimation on the fuel demand for the

planned voyage?

(2)

How to proceed if the draft of the ship will be different for the planned voyage, compared to

the previous voyage?

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Annex 1: Ship & Machinery Data

Container Ship 2.127 TEU

Main Engine: Sulzer 5RTA84C

MCR : 20.250 kW at 102 RPM

Power Generation

Two diesel generators Wrtsila 8L20 2x1600 kW

One emergency diesel generator 600 kW

Steam Generation

Auxiliary boiler, operation with MDO or HFO

Exhaust gas boiler

Sulzer RTA84C

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Annex 2: Available Fuel Reserve

HFO Volume (90%) Reserve

[m3] [m3] [C] [t]

HFO DB TK 1 750 0,0 35 0,0

HFO DB TK 2 750 102,7 52 99,0HFO HB TK 1 500 95,2 49 91,9

HFO HB TK 2 500 5,1 50 4,9

HFO Settling TK 1 80 0,5 38 0,5

HFO Settling TK 2 80 46,5 70 44,3

HFO Day TK 71 20,1 68 19,2

Total HFO = -

MDO Volume (90%) Reserve

[m3] [m3] [C] [t]

MDO Storage TK 1 227 54,8 37 47,9

MDO Storage TK 2 145 11,4 36 10,0

MDO Settling TK 1 80 1,7 38 1,5

MDO Settling TK 2 80 73,3 39 64,0

MDO Day TK 68 27,7 40 24,2

Total MDO = -

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Annex 3: Power demand and fuel consumption

1. Main Engine

Table 1: Data from the last voyage

Sea distance S = 1.404 nm

Average ship speed at sea Vs = 19,5 kn

Total fuel consumption

at sea passage HFO = 236,8 t

for manoeuvring MDO = 3,6 t

Table 2: Previous measurements under nearly the same conditions

n Vs Pb Bh

[rpm] [kn] [kW] [kg/h]

70 14,3 6.315 1.284

80 16,2 9.570 1.832

90 18,0 13.610 2.502

100 19,8 18.710 3.487

2. Power Generation

At sea passage on of the diesel generators is running. The average consumption at sea is 5,5 tons

MDO per day. During manoeuvring the consumption of the diesel generators is about 275 kg/h. In

the port 5,0 tons of MDO are used per day.

3. Steam Generation

At sea passage, all steam is produced by the exhaust gas boiler.

During manoeuvring and in the port, the auxiliary boiler is running, consuming 2,5 tons MDO per day.