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Ship Geometry, Stability and Trim(27)Resistance, Propulsion & Ship Manoeuvring(27)Ship Motions, Structures & Strength(23)Physical Oceanography, Offshore Structures & Port Engineering(14)

Ship Geometry, Stability and Trim

27 Questions

GATE→2026→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q1

MCQ[1 Mark]

Consider two configurations P and Q of a stationary ship floating in calm water with transverse sections as shown in the figure, where M is the metacentre, G is the centre of gravity, and B is the centre of buoyancy. Which ONE of the following statements is TRUE regarding the static stability of the ship?

(A)

Configuration P is stable and configuration Q is unstable.

(B)

Both configurations are stable.

(C)

Configuration P is unstable and configuration Q is stable.

(D)

Both configurations are unstable.

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q2

MCQ[1 Mark]

A ship floating in seawater has a TPC (Tonne Per Centimeter immersion) of 20. If bilge keel of total mass 65.1 tonne and volume $44\text{ m}^3$ is added to the ship, then the change in the mean draft is cm. Assume that after bilge keel fitment, the TPC remains constant, and the ship undergoes parallel sinkage. Density of seawater is $1025\text{ kg/m}^3$.

(A)

0.5

(B)

1

(C)

0.55

(D)

1.1

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q3

MSQ[1 Mark]

Which ONE or MORE of the following methods of shifting weights can be used to improve the transverse stability of a rectangular pontoon? Note: CG denotes the vertical centre of gravity of the pontoon.

(A)

From below the CG to above the CG

(B)

From above the CG to below the CG

(C)

From port to starboard at the same height from the keel

(D)

From forward to aft at the same height from the keel

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q4

NAT[1 Mark]

A vessel of $5000\text{ m}^3$ displacement floating in seawater has a rectangular tank of length 6 m and width 10 m. The tank is half-filled with seawater as shown in the figure. The virtual reduction in metacentric height due to free surface effect is m (answer in one decimal place).

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q5

MCQ[2 Marks]

A ship is undergoing a steady starboard turn. Assume that total hydrodynamic forces (Y) including the rudder forces act at the centre of buoyancy (B). If W is the weight of the ship, G is the centre of gravity and M is the transverse metacentre, then the magnitude of the heel angle ($\phi$) is given by Assume that $\phi$ is small.

(A)

$|\frac{Y \times BG}{W \times GM}|$

(B)

$|\frac{W \times BG}{Y \times GM}|$

(C)

$|\frac{W \times GM}{Y \x BG}|$ (typo in paper)

(D)

$|\frac{Y \times GM}{W \times BG}|$

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q6

NAT[2 Marks]

A ship of $4000\text{ m}^3$ displacement has a block coefficient of 0.8. If the beam is 0.1 times the length and twice the draught, then the length of the ship is m (answer in integer).

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q7

NAT[2 Marks]

A ship consumes 250 tonne of fuel when moving from sea to a river. On arrival, draught and trim (measured at rest) are the same as the corresponding values at sea. The displacement of the ship in seawater is tonne (answer in integer). The density of seawater and river water are $1025\text{ kg/m}^3$ and $1000\text{ kg/m}^3$ respectively.

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q8

MCQ[1 Mark]

A ship of 5000 tonne displacement has two empty rectangular double bottom tanks with dimensions:\nTank A: length 12 m, width 16 m, and height 2 m\nTank B: length 16 m, width 12 m, and height 2 m\nThe length of each tank is oriented along the length of the ship. It is required to ballast the ship with $192\text{ m}^3$ of seawater of density $1025\text{ kg/m}^3$.\nWhich one of the following scenarios will minimize the free surface effect?

(A)

100% of the given ballast water is filled in Tank A.

(B)

100% of the given ballast water is filled in Tank B.

(C)

50% of the given ballast water is filled in Tank A and the remaining in Tank B.

(D)

40% of the given ballast water is filled in Tank A and the remaining in Tank B.

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q9

MSQ[1 Mark]

For a freely floating body in water, which of the following degrees of freedom has/have inherent restoring force?

(A)

Sway

(B)

Surge

(C)

Heave

(D)

Pitch

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q10

NAT[1 Mark]

A ship of length 200 m has a beam of 25 m. She floats in seawater with an even keel draught of 5 m. The prismatic coefficient of the ship is 0.9; the mass displacement is 20500 tonne and the density of seawater is $1025\text{ kg/m}^3$.\nThe midship section coefficient is (rounded off to two decimal places).

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q11

MCQ[2 Marks]

A ship of length 100 m and displacement 5000 tonne floats even-keel at 6.5 m in fresh water of density $1000\text{ kg/m}^3$. The ship's hydrostatic properties are given.\nThe ship has moved to seawater of density $1025\text{ kg/m}^3$ without change in the displacement. The new forward and aft draughts are respectively.

(A)

6.04 m and 6.54 m

(B)

6.30 m and 6.64 m

(C)

6.64 m and 6.30 m

(D)

6.30 m and 6.30 m

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q12

NAT[2 Marks]

A ship of 3300 tonne displacement is undergoing an inclining experiment in seawater of density $1025\text{ kg/m}^3$. A mass of 6 tonne is displaced transversely by 12 m as shown in the figure. This results in 0.12 m deflection of a 11 m long pendulum suspended from the centerline. The transverse metacenter of the ship is located at 7.25 m above the keel.\nThe distance of the center of gravity from the keel is m (rounded off to two decimal places).

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q13

MCQ[1 Mark]

The GZ curve for a stable ship is shown in the figure, where P is a point of inflection on the curve. Match the labels in Column 1 with the corresponding descriptions in Column 2: Column 1: P, Q, R, ST Column 2: I: Angle of vanishing stability II: Maximum GZ III: Initial GM (slope at origin) IV: Deck edge immersion

(A)

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

(B)

P-I; Q-II; ST-III; R-IV (variant)

(C)

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

(D)

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

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q14

NAT[1 Mark]

An 80 m long barge with rectangular cross-section of 12 m beam and 4 m draft floats at even keel. The transverse metacenter (KM) above the keel is m.

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q15

NAT[1 Mark]

A cube-shaped pontoon with 200 tonnes of mass placed on it, floats with a freeboard of 1 m in fresh water. When the mass is removed, the pontoon floats with a freeboard of 3 m. The length of the pontoon is m (rounded off to two decimal places).

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q16

MCQ[2 Marks]

A ship with a displacement of 10000 tonnes has the center of gravity at 4 m above the keel and 1.5 m forward of midship. If 2000 tonnes of cargo is placed at 10 m above the keel and 1.5 m aft of midship, then the new position of the center of gravity is

(A)

5 m above the keel and 1 m aft of midship

(B)

6 m above the keel and 1 m forward of midship

(C)

6 m above the keel and 1 m aft of midship

(D)

5 m above the keel and 1 m forward of midship

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q17

MCQ[2 Marks]

The waterplane area of a ship floating in sea water is $2000\text{ m}^2$. The density of seawater is $1025\text{ kg/m}^3$. If a mass of 246 tonnes is added to the ship, then the TPC (Tonnes Per Centimeter immersion) and increase in draft (in cm) respectively are

(A)

20.50 and 12

(B)

20 and 12.3

(C)

20.50 and 24

(D)

10.25 and 24.6

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q18

NAT[2 Marks]

A ship of 5000 tonnes displacement has a rectangular tank 6 m long and 10 m wide, half-filled with oil of relative density 0.8. The virtual reduction in the transverse metacentric height of the ship due to free surface effect of the oil in the tank is m.

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q19

MCQ[1 Mark]

In the following "GZ (righting lever arm)" versus "angle of heel" curve, the point 'X' indicates

(A)

angle of loll

(B)

angle of vanishing stability

(C)

deck edge immersion angle

(D)

trim angle

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q20

MCQ[1 Mark]

Comparing a catamaran (with a separation between demi-hulls) and a mono-hull craft of the same displacement and water plane area, the initial metacentric radius of the catamaran will be

(A)

same as that of the mono-hull

(B)

one-half of the mono-hull

(C)

greater than that of the mono-hull

(D)

one-third of the mono-hull

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q21

NAT[1 Mark]

A ship of length 180 m has a displacement of 14400 tonnes and is floating on an even keel in sea water of density $1025\text{ kg/m}^3$. The trim changes by 0.18 m when a weight of 120 tonnes that is already onboard, is shifted 24 m forward.\nThe longitudinal metacentric height is m.

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q22

NAT[1 Mark]

An oil tanker of breadth 20 m and having a displacement of 24000 tonnes in sea water (density of sea water $=1025\text{ kg/m}^3$) is carrying oil of relative density 0.8 in 9 longitudinally distributed tanks which are all half-filled. Each longitudinal tank is 12 m long and 16 m wide.\nThe apparent change in vertical center of gravity, due to the presence of oil in the tanks is m (round off to one decimal place)

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q23

MCQ[2 Marks]

Two 30 m long bilge keels of mass 40 tonnes each, are fitted at the turn of the bilge on port and starboard sides of a ship. The cross section of the bilge keel is shown in the following figure. Assume density of water $=1000\text{ kg/m}^3$. If the TPC (tonnes per centimeter) immersion of the ship is 50, then the change in the mean draft is cm

(A)

1

(B)

0.8

(C)

0.6

(D)

1.6

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q24

NAT[2 Marks]

A vessel of 100 m length has a constant triangular cross-section with a depth of 12 m and breadth of 15 m as shown in following figure. The vessel has a vertical center of gravity (KG) = 6.675 m. The minimum draft (d), at which the vessel will become stable is m (round off to one decimal place)

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q25

MCQ[1 Mark]

The margin line used for the floodable length calculation of a ship is

(A)

76 mm above the ship's baseline

(B)

76 mm inside the zero-buttock line in the profile view of the ship's lines plan

(C)

a line drawn 76 mm parallel to and below the watertight main deck at side

(D)

a line drawn 76 mm parallel to and below the watertight main deck along the ship's centerline if the ship has camber

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q26

MSQ[2 Marks]

If a ship hull is subdivided into different watertight compartments, which of the following statements are TRUE?

(A)

It improves the ship stability in damaged conditions

(B)

It increases the ship hull strength

(C)

It reduces the ship intact stability

(D)

It provides more options to carry different types of cargo

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Ship Geometry, Stability and Trim

Q27

NAT[2 Marks]

A rectangular barge has length (L) of 100 m, breadth (B) of 18 m and depth (D) of 10 m. It is subdivided transversely into four equal compartments of equal length with the end compartments loaded fully with oil of density $=0.9\text{ tonne/m}^{3}$. The barge floats in water having a density of $1000\text{ kg/m}^{3}$. If the hull structural weight is ignored, then the transverse metacentric height of the barge is m (correct to two decimal places).

Explanation

Resistance, Propulsion & Ship Manoeuvring

27 Questions

GATE→2026→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q28

MCQ[1 Mark]

The sway-yaw coupled maneuvering equation of motion for a ship is given. For a control-fixed straight-line stability, the eigenvalues of the system matrix should be

(A)

real and negative

(B)

real and positive

(C)

complex numbers with positive real part and negative imaginary part

(D)

zero

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q29

MSQ[1 Mark]

During a captive maneuvering model test of a ship with a rudder, which ONE or MORE of the following coefficients can be calculated using an oblique towing test (straight line test with a drift angle)?

(A)

$Y_v$ and $Y_{vvv}$

(B)

$N_v$ and $N_{vvv}$

(C)

$Y_{v\delta\delta}$ and $N_{v\delta\delta}$

(D)

$N_{r\delta\delta}$ and $N_{vr\delta}$

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q30

MCQ[2 Marks]

Which ONE of the following options CORRECTLY matches the efficiencies in Column 1 with the corresponding definitions in Column 2? Column 1: I. Gear efficiency II. Shaft efficiency III. Hull efficiency IV. Propeller (behind-hull) efficiency Column 2: P. Ratio of delivered power to shaft power Q. Ratio of shaft power to brake power R. Ratio of thrust power to delivered power 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

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q31

MCQ[2 Marks]

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

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q32

NAT[2 Marks]

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).

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q33

MCQ[2 Marks]

Consider a Planar Motion Mechanism (PMM) test of a ship model in a towing tank. The transverse motion of the model from the centerline of the tank is described by $y=a_{0}\cos(\omega t)$, where $\omega$ is the angular frequency. The carriage speed is $3\text{ m/s}$, $\omega=\frac{\sqrt{3}}{2}\text{ rad/s}$ and the maximum drift angle during the test is $30^{\circ}$.\nThe amplitude of oscillation $a_{0}$ lies between

(A)

0.2 m and 0.4 m

(B)

0.5 m and 0.7 m

(C)

1.0 m and 1.2 m

(D)

1.9 m and 2.1 m

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q34

NAT[1 Mark]

The dynamics of a 90 m long ship are governed by the non-dimensional Nomoto equation. The magnitude of Nomoto gain $|K'|=\frac{72}{35\pi}$ and that of Nomoto time constant $|T'|=\frac{288}{35\pi}$.\nThe steady turning radius of the ship for a $35^{\circ}$ turning circle maneuver is m (answer in integer).

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q35

MCQ[2 Marks]

Consider a rectangular barge of length (L) 100 m, breadth 25 m and draught 10 m. The barge has the following non-dimensional hydrodynamic derivatives with respect to a coordinate system whose origin is at the center of gravity. $Y_v' = -1000 \times 10^{-5}$, $N_r' = -800 \times 10^{-5}$ $N_v' = -200 \times 10^{-5}$, $Y_r' = 100 \times 10^{-5}$\nThe stability criterion $C'$ is given by $C' = Y_v'(N_r' - m'x_G') - (Y_r' - m')N_v'$.\nWhich one of the following is correct regarding the controls-fixed straight-line stability?

(A)

Unstable with C' = -1.8 x 10^{-5}

(B)

Stable with C' = 3.2 x 10^{-5}

(C)

Stable with C' = -1.8 x 10^{-5}

(D)

Unstable with C' = 3.2 x 10^{-5}

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q36

MCQ[2 Marks]

A ship has a propeller of 5 m pitch rotating at 120 rpm. The ship travels at $8\text{ m/s}$ and the wake fraction is 0.25.\nThe 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

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q37

NAT[2 Marks]

A ship moving at a steady forward speed of $10\text{ m/s}$ experiences a total resistance of $140\text{ kN}$. The Quasi Propulsive Coefficient (QPC) is 0.70; the propeller shaft losses are 5% and the mechanical efficiency of the main engine is 80%.\nThe indicated power of the main engine is kW (rounded off to two decimal places).

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q38

MCQ[1 Mark]

A ship with a standard right-handed coordinate system has positive x, y and z axes respectively pointing towards bow, starboard and down as shown in the figure. If the ship takes a starboard turn, then the drift angle, sway velocity and the heel angle of the ship for a steady yaw rate respectively are

(A)

positive, negative and positive

(B)

negative, positive and positive

(C)

negative, positive and negative

(D)

positive, negative and negative

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q39

MCQ[1 Mark]

A ship with controls fixed, is modeled as a two degrees of freedom system. For the linear maneuvering equations of motion for coupled sway and yaw, if the derived eigenvalues are real and negative, then the ship must possess

(A)

positional motion stability

(B)

directional stability

(C)

straight line stability

(D)

both directional and positional motion stabilities

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q40

NAT[1 Mark]

A 100 m long ship has a cruising speed of 25 knots. A geometrically similar model of 4 m length is used for resistance prediction in a towing tank. The corresponding speed of the model is knots.

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q41

MCQ[2 Marks]

The open water characteristics of a propeller is shown in the figure. Match the labels in Column 1 with the corresponding descriptions in Column 2: Column 1: K_T, 10K_Q, \eta_0, etc. Column 2: I: Bollard pull condition ($J=0$) II: Feathering condition III: Wind milling condition IV: Efficiency curve

(A)

P-I; Q-II; Q-III; R-IV (matching option A)

(B)

Option B

(C)

Option C

(D)

Option D

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q42

NAT[2 Marks]

A propeller disc of diameter 2 m produces a thrust of 88 kN while advancing at a speed of $5\text{ m/s}$ in fresh water of density $1000\text{ kg/m}^3$. Based on the axial momentum theory, the propeller efficiency is % (rounded off to one decimal place).

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q43

MCQ[1 Mark]

The time series of rudder angle ($\delta$) and heading angle ($\psi$) during a ship's maneuver are shown in the following figure. Identify the maneuver and the associated parameters (p, q, r and s)

(A)

turning maneuver...

(B)

spiral maneuver...

(C)

zig-zag maneuver; p: heading angle, q: rudder angle, r: 1st overshoot angle, s: 2nd overshoot angle

(D)

zig-zag maneuver; p: heading angle...

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q44

MCQ[2 Marks]

The trajectory of a model ship during a pure sway PMM test is shown below. The steady forward speed, u is $2.0\text{ m}/\text{s}$. The maximum amplitude of sway motion, $y_{Max}$ is 0.5 m and its period is 8 s.\nThe magnitude of maximum drift angle, in degrees (round off to the nearest integer), and the magnitude of maximum sway acceleration, in $\text{m/s}^2$ (round off to one decimal place), of the model respectively are

(A)

11 and 0.3

(B)

13 and 0.5

(C)

15 and 0.2

(D)

9 and 0.1

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q45

MCQ[2 Marks]

A ship of length 125 m has a design speed of 25 knots ($1\text{ knot} = 0.5144\text{ m}/\text{s}$). A 5.0 m long geometrically similar model with wetted surface area of $4\text{ m}^2$ has a coefficient of residuary resistance of $1.346 \times 10^{-3}$ at the corresponding speed.\nThe ship's residuary resistance in kN (in sea water of density $1025\text{ kg}/\text{m}^3$) 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

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q46

NAT[2 Marks]

For a ship of length $L=100\text{ m}$, the distance between the bow and stern pressure system is $0.942L$. Assume $g=10\text{ m}/\text{s}^2$. The ship velocity corresponding to the prismatic hump of the wave making resistance curve is m/s (round off to one decimal place)

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q47

NAT[2 Marks]

For a marine screw propeller, the open water characteristics at $J=0.6$ are $K_{T}=0.1336$ and $10K_{Q}=0.2010$. The open water propeller efficiency $\eta_{o}$, is (round off to two decimal places)

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q48

MCQ[1 Mark]

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

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q49

MCQ[1 Mark]

A 1:20 scaled model of a surface ship is tested in a towing tank. The model is towed at $3\text{ m/s}$ and drag force measured is 10 N.\nThe velocity of the prototype and the drag force acting on the prototype, respectively, are m/s and kN.

(A)

60.4 and 80

(B)

13.4 and 80

(C)

13.4 and 4

(D)

60.4 and 4

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q50

MSQ[1 Mark]

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

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q51

NAT[1 Mark]

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.

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q52

NAT[1 Mark]

Assume that a ship has length $L=200\text{ m}$ and operates at a design speed $U=12\text{ m}/\text{s}$. If in a turning circle maneuver, the ship exhibits a steady turning diameter of 6L, then the yaw rate of the ship is rad/s (correct to two decimal places).

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q53

MCQ[2 Marks]

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

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Resistance, Propulsion & Ship Manoeuvring

Q54

NAT[2 Marks]

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).

Explanation

Ship Motions, Structures & Strength

23 Questions

GATE→2026→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q55

MCQ[1 Mark]

The RAO (Response Amplitude Operator) of a floating body with no forward speed is denoted by $H(\omega)$. If it encounters a wave spectrum $S(\omega)$, then its response spectrum is

(A)

$H(\omega)S(\omega)$

(B)

$|H(\omega)|^2 S(\omega)$

(C)

$|H(\omega)|^3 S(\omega)$

(D)

$|H(\omega)|S(\omega)$

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q56

MSQ[1 Mark]

The weight of a ship is uniformly distributed along its length. Under which ONE or MORE of the following conditions will the ship be subjected to hogging moment? Note: The weight is equal to buoyancy in all of the following conditions.

(A)

When buoyancy per unit length is greater than weight per unit length amidships

(B)

When weight per unit length is greater than buoyancy per unit length in the bow and stern region

(C)

When the ship is on a single wave with its crest at midship and troughs at the bow and stern

(D)

When the ship is on a single wave with its crests at the bow, stern and the trough at midship

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q57

MCQ[2 Marks]

A ship undergoing harmonic oscillation has an uncoupled heave motion, $\eta_3(t)$, governed by the following equation: $$(M+A_{33})\ddot{\eta}_3(t) + B_{33}\dot{\eta}_3(t) + K_{33}\eta_3(t) = f_3(t)$$ If $F_3(\omega)$ is the Fourier transform of $f_3(t)$, then the response in the frequency domain can be written as

(A)

$\frac{F_3(\omega)}{-\omega^2(M+A_{33}) + i\omega B_{33} + K_{33}}$

(B)

$\frac{iF_3(\omega)}{-\omega^2(M+A_{33}) + i\omega B_{33} + K_{33}}$

(C)

$\frac{F_3(\omega)}{\omega^2(M+A_{33}) - i\omega B_{33} + K_{33}}$

(D)

$\frac{F_3(\omega)}{\omega^2(M+A_{33}) + \omega B_{33} + K_{33}}$

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q58

NAT[2 Marks]

A box shaped pontoon of length 100 m, breadth 12 m and draft 10 m is floating in water of density $1\text{ tonne/m}^3$. The roll radius of gyration is 1% of the ship's length and the roll added mass moment of inertia is 20% of the roll mass moment of inertia. The vertical centre of buoyancy is located at half of the draft, and the vertical centre of gravity is at 6 m from the keel. The roll natural frequency of the pontoon is rad/s (rounded off to two decimal places). Assume $g = 10\text{ m/s}^2$.

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q59

NAT[2 Marks]

A ship is moving at $10\text{ m/s}$ in head sea condition. A person on board counts the time period between two successive wave crests as $\pi$ seconds. The frequency of the incoming wave is rad/s (answer in integer). Assume $g = 10\text{ m/s}^2$.

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q60

MCQ[1 Mark]

The midship section of a barge of breadth W and depth H is shown in the figure. All plate thicknesses are equal. The barge is subjected to a longitudinal bending moment in the upright condition.\nWhich one of the following statements is correct?

(A)

Magnitude of longitudinal bending stress is maximum at point P and magnitude of vertical shear stress is maximum at point Q.

(B)

Magnitude of longitudinal bending stress is maximum at point S and magnitude of vertical shear stress is maximum at point R.

(C)

Magnitude of longitudinal bending stress is maximum at point Q and magnitude of vertical shear stress is maximum at point S.

(D)

Magnitude of longitudinal bending stress is maximum at point R and magnitude of vertical shear stress is maximum at point P.

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q61

MSQ[2 Marks]

Consider a case where the load Q for a ship structure has only statistical uncertainties. The probability density function of the load $p_Q(x)$ is shown in the figure. The characteristic limit value of the load ($Q_{L_c}$) is 1.5 and factor of safety is 1.\nWhich of the following probability of exceedance value(s) of the load will lead to a safe design?

(A)

0.05

(B)

0.10

(C)

0.15

(D)

0.20

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q62

NAT[2 Marks]

A freely-floating rectangular barge of length 200 m is divided into five equal compartments. In light-weight condition, the weight and buoyancy are uniformly distributed along the length of the barge. Assume $g=9.81\text{ m/s}^2$.\nIf 500 tonne of liquid cargo is added to each of the two end compartments as shown in the figure, then the maximum bending moment is MN-m (rounded off to two decimal places).

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q63

NAT[2 Marks]

A multi-cell midship section of a ship with $B=40\text{ m}$ and $D=20\text{ m}$ is shown in the figure. The shear-flows are given as $q_{1}=q_{2}=q_{3}=0.9376\text{ MN/m}$.\nThe applied twisting moment on the midship section is MN-m (rounded off to two decimal places).

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q64

MSQ[1 Mark]

Which of the following hull distortion(s) is/are resisted by a ship's transverse bulkhead?

(A)

Racking

(B)

Torsion

(C)

Longitudinal bending

(D)

Horizontal bending

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q65

MSQ[1 Mark]

Which of the following statement(s) is/are correct about strip theory?

(A)

It can be used to calculate the surge added mass

(B)

It is a two-dimensional theory

(C)

It can be used to calculate the pitch added mass

(D)

It can be used to calculate the coupled sway, roll and yaw added mass

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q66

MCQ[2 Marks]

Consider a two-dimensional ship section as shown in the figure. About the point O, let the sway added mass components be $a_{22}$ and $a_{24}$ and roll added moment of inertia be $a_{44}$. The clockwise roll angle is considered positive. The roll added mass due to roll, about P which is at a distance $Z_P$ above O is given by

(A)

$a_{44} - a_{24} z_P$

(B)

$a_{44} - a_{22} z_P - a_{24} z_P$

(C)

$a_{44} - a_{22} z_P + a_{24} z_P$

(D)

$a_{22} + a_{24} + a_{44}$

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q67

NAT[2 Marks]

The wave spectrum and the ship heave Response Amplitude Operator (RAO) are shown in the figure. The variance of the heave motion is $m^2$ (rounded off to three decimal places).

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q68

MCQ[1 Mark]

The buoyancy curve variation of a ship floating in still water and in waves is shown in the following figure. The total area under each curve is the same. The cases 'X' and 'Y' correspond to

(A)

X: wave crest amidships...

(B)

X: wave trough amidships...

(C)

X: wave trough amidships, Y: wave crest amidships

(D)

X: wave crest is amidships, Y: wave trough is amidships

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q69

MSQ[1 Mark]

A stationary ship has longitudinal symmetry. The surge, sway and heave motions are represented by indices 1-2-3, respectively and roll, pitch and yaw motions are represented by indices 4-5-6, respectively. Which of the following are TRUE about the added mass ($A_{ij}$)?

(A)

$A_{35} = A_{53}$

(B)

$A_{62} = A_{26}$

(C)

$A_{46} = A_{64}$

(D)

$A_{33} = A_{55}$

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q70

MSQ[1 Mark]

A rectangular barge is freely floating in a drydock as shown in the following figure. For longitudinal strength analysis which of the following are TRUE?

(A)

The barge is considered as a free-free beam

(B)

At aft and forward ends: shear force = 0, bending moment = 0

(C)

The barge is considered as a fixed-fixed beam

(D)

At aft and forward ends: shear force != 0, bending moment != 0

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q71

MCQ[2 Marks]

A 'T' section is welded to the flat bottom shell plate of a ship as shown in the following figure (bottom shell longitudinal). The neutral axis of the ship's midship section is 14 m above the bottom shell plate. The distance (X) of neutral axis of the 'T' section from the ship's neutral axis is m (round off to two decimal places)

(A)

12.63

(B)

13.63

(C)

15.24

(D)

11.24

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q72

NAT[2 Marks]

A marker buoy of mass 1500 kg floating in sea water of density $1025\text{ kg}/\text{m}^3$, consists of a cylinder and cone as shown in the following figure. The buoy is suitably ballasted to make it stable in the floating condition. The buoy is subjected to an external periodic excitation force in Newton, $F_{e}(t)=2000\sin(1.25t)$.\nIgnore damping effects and assume $g=9.81\text{ m}/\text{s}^2$, added mass $=25\%$ of the mass of the buoy.\nThe maximum heave response amplitude of the buoy is m (round off to one decimal place)

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q73

MCQ[1 Mark]

Consider a rectangular box barge of length 80 m, breadth 20 m and depth 15 m floating at an even draught of 10 m. Assume that the heave added mass of the vessel is equal to its mass displacement and the acceleration due to gravity is $9.81\text{ m/s}^2$.\nThe heave natural period of the vessel lies in between s.

(A)

1 and 5

(B)

6 and 10

(C)

11 and 15

(D)

16 and 20

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q74

MSQ[1 Mark]

For a rigid vessel at sea, which of the following statements are TRUE?

(A)

Static and dynamic environmental loads are dependent on the structural strength of the vessel

(B)

Static and dynamic environmental loads are NOT dependent on the structural strength of the vessel

(C)

Static and dynamic environmental loads are dependent on the geometry of the vessel

(D)

Static and dynamic environmental loads are NOT dependent on the geometry of the vessel

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q75

MSQ[2 Marks]

An autonomous underwater vehicle is made of a long cylinder with a semi-ellipsoid at the forward end and a hemisphere at the aft end as shown in the figure. The origin of the reference frame is located at the centroid of the cylinder.\nThe positive x, y and z axes, respectively, are pointing towards forward, port and upward directions. The surge, sway and heave motions are represented by indices 1-2-3 and roll, pitch and yaw motions are represented by indices 4-5-6, respectively.\nIf $A=[A_{ij}]$ is the added mass matrix, then which of the following are NOT zero?

(A)

$A_{15}$

(B)

$A_{35}$

(C)

$A_{46}$

(D)

$A_{26}$

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q76

MSQ[2 Marks]

Consider the midship section of a vessel with the centerline (CL) and neutral axis (NA) as shown in the figure. Assume that the cross-section is symmetric about the centerline, the plate thickness is uniform throughout the section and $h_{1}<h_{2}$.\nWhen the vessel is subjected to a vertical bending moment in its upright condition, which of the following statements are TRUE?

(A)

Magnitude of shear stress is maximum at points P and S

(B)

Magnitude of shear stress is minimum at points Q and U

(C)

Magnitude of bending stress is maximum at points S and T

(D)

Magnitude of bending stress is minimum at points Q and U

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Ship Motions, Structures & Strength

Q77

NAT[2 Marks]

Consider a ship with one half of its midship cross-section, as shown in the figure, with moulded breadth B of 30 m and moulded depth D of 9 m.\nAssume the following:\nThe deck, side shell and bottom plate have the same thickness\nThe yield stress of the material is 240 MPa\nThe section is subjected to a vertical bending moment of 712.8 MNm\nIgnore the self-moment of inertia of the deck and bottom plating in calculations.\nThe distance of the fiber farthest from the neutral axis can be considered excluding the plate thickness.\nIf the maximum bending stress is equal to the yield stress, then the plate thickness is mm (rounded off to one decimal place).

Explanation

Physical Oceanography, Offshore Structures & Port Engineering

14 Questions

GATE→2026→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q78

MSQ[1 Mark]

Which of the following structures is/are mainly used for harbor berthing?

(A)

Dolphins

(B)

Jetty

(C)

Quay

(D)

Jacket

Explanation

GATE→2026→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q79

NAT[2 Marks]

A static system consisting of air, water, oil and mercury is shown in the figure. If Q is open to the atmosphere, the gauge pressure at P is kPa (rounded off to one decimal place). Consider $g = 10\text{ m/s}^2$, $h_1 = 0.5\text{ m}$, $h_2 = 0.7\text{ m}$, $h_3 = 0.8\text{ m}$, density of $\text{water} = 1000\text{ kg/m}^3$, $\text{SG}_{oil} = 0.9$ and $\text{SG}_{mercury} = 13.6$.

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q80

MCQ[1 Mark]

Which one of the following wave energy spectra is formulated for two peaks?

(A)

Pierson-Moskowitz spectrum

(B)

JONSWAP spectrum

(C)

Ochi-Hubble spectrum

(D)

Neumann spectrum

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q81

MCQ[1 Mark]

According to linear water wave theory, at a point on the free surface of a regular wave, the phase difference between the free surface elevation and the horizontal water particle acceleration is

(A)

$0^\circ$

(B)

$45^\circ$

(C)

$90^\circ$

(D)

$135^\circ$

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q82

MSQ[1 Mark]

Choose the correct statement(s) from the following with respect to a ship generated Kelvin wave pattern in deep water.

(A)

A system of transverse waves and divergent waves are observed behind the ship.

(B)

A system of transverse waves and divergent waves are observed in front of the ship.

(C)

The waves are contained in a sector originating at the bow with a half angle of $9^\circ28'$

(D)

The amplitude of wave components decrease as they propagate.

Explanation

GATE→2025→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q83

NAT[2 Marks]

An ocean wave is propagating from deep to shallow water. The wave is approaching the coast at $45^{\circ}$ counterclockwise from the shore normal with an initial phase speed of $12.5\text{ m/s}$. After entering the shallow water, the wave direction becomes $30^{\circ}$ counterclockwise from the shore normal.\nThe phase speed of the wave at the shallow water is $m/s$ (rounded off to one decimal place).

Explanation

GATE→2024→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q84

NAT[2 Marks]

An ocean wave of period 8 s and height 2 m is propagating in the Indian Ocean from south to north. According to linear wave theory, for the wave to be considered as a deep-water wave, the minimum water depth should be m (rounded off to the nearest integer).

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q85

MCQ[1 Mark]

From the following, choose the offshore platform that can be used ONLY for offshore drilling purpose.

(A)

Jacket platform

(B)

Jackup platform

(C)

Tension leg platform

(D)

SPAR

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q86

NAT[1 Mark]

For a regular sinusoidal wave propagating in deep water having wave height of 3.5 m and wave period of 9 s, the wave steepness is (round off to three decimal places).

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q87

MCQ[2 Marks]

The layout of a Tension Leg Platform (TLP) is shown in the following figure. It consists of four interconnected pontoons at the bottom and four cylindrical columns, which support the working platform at the top. The density of sea water is $1025\text{ kg/m}^3$. Neglect the weight and buoyancy of the tethers. During operation, the maximum mass (in metric tonnes) of the entire structure must lie between

(A)

18630 and 18635

(B)

28635 and 28640

(C)

25655 and 25660

(D)

24560 and 24565

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q88

MCQ[2 Marks]

The heave natural frequencies of a Jacket structure, FPSO and a semi-submersible are $\omega_J$, $\omega_F$ and $\omega_S$ respectively. Each one of them has a pay load capacity of 10000 tonnes. Which of the following is TRUE?

(A)

$\omega_J < \omega_F < \omega_S$

(B)

$\omega_J > \omega_F > \omega_S$

(C)

$\omega_J < \omega_S < \omega_F$

(D)

$\omega_J > \omega_S > \omega_F$

Explanation

GATE→2023→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q89

NAT[2 Marks]

A tsunami that originated off the Indonesian coast has propagated towards the east-coast of India. It enters the continental shelf at 150 km away from the coast of Chennai. If the average water depth is 80 m from the coast to the continental shelf and 20 minutes is the tsunami period, the time taken by the tsunami to reach the coast of Chennai on entering the continental shelf is hours (round off to two decimal places)

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q90

MCQ[2 Marks]

Consider the wave elevation spectrum $S_{\eta\eta}(\omega)$ as shown in the figure. Then, the significant wave height is m.

(A)

2

(B)

4

(C)

6

(D)

8

Explanation

GATE→2022→Naval Architecture and Ocean Engineering→Physical Oceanography, Offshore Structures & Port Engineering

Q91

NAT[2 Marks]

Consider a ship with a forward speed U of $9.81\text{ m/s}$ moving in deep waters. A wave is incident at an angle $\beta=120^{\circ}$ to the longitudinal axis of the ship as shown in figure. Assume acceleration due to gravity $g=9.81\text{ m/s}^{2}$. If a person onboard the ship observes the encounter period of the incident wave to be 4.187 s, then the actual period of the wave is s (rounded off to one decimal place).

Explanation