Resistance and Propulsion - Naval Architecture and Ocean Engineering - Naval Architecture & Marine Engineering Previous Year Questions

1

2022 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture & Marine Engineering (NM) 2022

A 10000 tonne displacement container ship’s main propulsion engine has a brake power equal to 46 MW and its service speed is 25 knots. Considering the engine brake power as double the effective power of the ship, then the ship resistance at the service speed lies in between ___________ kN.

A

3285 and 3315

B

6785 and 6815

C

885 and 915

D

1785 and 1815

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2

2022 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture & Marine Engineering (NM) 2022

If a ship enters shallow water from deep water, maintaining the same speed, then which of the following are TRUE?

A

Resistance increases

B

Trim changes

C

Resistance decreases

D

Draught increases

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3

2022 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture & Marine Engineering (NM) 2022

The diameter and rotating speed of a cargo ship propeller are 7.5 m and 120 RPM, respectively. An open water test is to be performed in a towing tank with a propeller model of 300 mm diameter. The corresponding propeller model speed is ______ RPM.

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4

2022 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture & Marine Engineering (NM) 2022

For a container ship, the propeller open water efficiency, thrust deduction fraction and wake fraction are 0.60, 0.19 and 0.25, respectively. If the relative rotative efficiency of the propeller is 1.0, then the hull efficiency and quasi-propulsive efficiency of the propeller, respectively, are

A

1.080 and 0.648

B

0.608 and 0.556

C

0.926 and 0.648

D

0.926 and 0.556

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5

2022 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture & Marine Engineering (NM) 2022

A propeller rotating at a speed of 108 RPM behind the ship produces a thrust of 720 kN with a torque of 700 kNm, when it travels at a speed of 15 knots. In open water, this propeller rotating at the same speed, produces the same thrust at an advance speed of 12 knots, and develops the same torque at an advance speed of 12.3 knots. Then, the average of the wake fractions is __________ (correct to two decimal places).

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6

2023 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture & Marine Engineering (NM) 2023

A ship of length 125 m has a design speed of 25 knots (1 knot = 0.5144 m/s). A 5.0 m long geometrically similar model with wetted surface area of 4 m² has a coefficient of residuary resistance of 1.346 x 10⁻³ at the corresponding speed. The ship's residuary resistance in kN (in sea water of density 1025 kg/m³), and the model speed in knots (round off to the nearest integer) respectively are

A

285 and 5

B

17 and 5

C

285 and 1

D

17 and 1

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7

2025 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture & Marine Engineering (NM) 2025

A ship has a propeller of 5 m pitch rotating at 120 rpm. The ship travels at 8 m/s and the wake fraction is 0.25. The apparent slip ratio and real slip ratio are _____ respectively.

A

0.20 and 0.40

B

0.40 and 0.20

C

0.20 and 0.25

D

0.25 and 0.20

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8

2025 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture & Marine Engineering (NM) 2025

A ship moving at a steady forward speed of 10 m/s experiences a total resistance of 140 kN. The Quasi Propulsive Coefficient (QPC) is 0.70; the propeller shaft losses are 5% and the mechanical efficiency of the main engine is 80%.

The indicated power of the main engine is ______ kW (rounded off to two decimal places).

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9

2026 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture and Marine Engineering (NM) 2026

Which ONE of the following options CORRECTLY matches the efficiencies in Column 1 with the corresponding definitions in Column 2?

Column 1	Column 2
I Gear efficiency	P Ratio of delivered power to shaft power
II Shaft efficiency	Q Ratio of shaft power to brake power
III Hull efficiency	R Ratio of thrust power to delivered power
IV Propeller (behind-hull) efficiency	S Ratio of effective power to thrust power

A

I-Q; II-P; III-S; IV-R

B

I-P; II-S; III-R; IV-Q

C

I-P; II-R; III-Q; IV-S

D

I-S; II-R; III-Q; IV-P

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10

2026 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture and Marine Engineering (NM) 2026

The figure depicts the cavitation pattern of a propeller.
Which ONE of the following options CORRECTLY gives the description for the labels P, Q, R, S, respectively in the figure?

A

Face cavitation, Bubble cavitation, Back cavitation, Tip cavitation

B

Back cavitation, Bubble cavitation, Face cavitation, Tip cavitation

C

Bubble cavitation, Face cavitation, Tip cavitation, Back cavitation

D

Tip cavitation, Face cavitation, Bubble cavitation, Back cavitation

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11

2026 · Naval Architecture & Marine Engineering · Naval Architecture and Ocean Engineering · Resistance and Propulsion

Naval Architecture and Marine Engineering (NM) 2026

A propeller of 4 m pitch is rotating at 120 rpm. It has a behind-hull propeller efficiency of 60% and a real slip of 25%.
If the power delivered to the propeller is 2800 kW, then the thrust produced by it is ______ kN (answer in integer).

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