List of top Naval Architecture and Ocean Engineering Questions asked in GATE NM

Consider a rectangular plate with in-plane loads. The stress at an arbitrary angle \( \theta \) is given by \( \sigma_x \), \( \sigma_y \), and \( \tau_{xy} \) as shown in the figure. If the principal plane is at \( \theta = 45^\circ \), and the principal stresses are \( \sigma_x = 8 \, \text{N/mm}^2 \) and \( \sigma_y = 3 \, \text{N/mm}^2 \), then the corresponding \( \tau_{xy} \) is …………… \( \text{N/mm}^2. \)

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 the free surface effect of the oil in the tank is ……….. cm.

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 …………. (rounded off to the nearest integer).

Consider a gas turbine combustor with air as the working fluid. The flow enters the device at 500 K and leaves at 1400 K with a mass flow rate of 0.1 kg/s. The changes in kinetic energy and potential energy of the flow are neglected. Assuming \( C_p = 0.717 \, \text{kJ/kg-K} \) and \( R = 0.287 \, \text{kJ/kg-K} \), the rate of heat addition is kW (rounded off to the nearest integer).

Consider a circular cylinder of diameter 0.5 m and length 2 m, rotating in clockwise direction at a speed of 100 rpm in a flow of velocity 2 m/s. Assume the density of the fluid as 1.225 kg/m\(^3\) and \( \pi = 3.14 \). By Kutta-Joukowski theorem, the lift force on the cylinder is \(\_\_\_\_\_\) N (rounded off to the nearest integer).

A new absolute temperature scale is proposed based on a Carnot engine operating between hot and cold reservoirs of temperatures \(T_L\) and \(T_H\) respectively. Let \(Q_L\) and \(Q_H\) be the respective heat transfers, with the relation given by \( \frac{T_L}{T_H} = \frac{Q_L}{Q_H} \). On the new scale, the difference between the steam and ice points of water is 500 units and the efficiency of the engine is 0.268. The steam point of water on this scale is .......... units (rounded off to the nearest integer).

A ship travelling in head seas experiences a bending moment of 200 MN-m. The ship’s cross-section is assumed to be a box girder of 30 m beam and 10 m depth with a 10 mm plate thickness. The maximum bending stress is \_\_\_ MPa (rounded off to the nearest integer).

Consider model testing where \( \lambda \) is the prototype-to-model length scale ratio. Let \( v_p \) and \( v_m \) denote the corresponding fluid kinematic viscosities. If Froude and Reynolds similarities are maintained between the prototype and model, then which one of the following is correct?

In the solution of statically indeterminate problems, Castigliano’s second theorem employs the

A ship with a displacement of 10,000 tonnes has the center of gravity at 4 m above the keel and 1.5 m forward of midship. If 2,000 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:

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

Which of the following statement(s) is/are correct for a thermodynamic closed system?

For a plane strain problem in the \( xy \) plane, it is necessary that:

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

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

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

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)

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

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 m\(^2\) has a coefficient of residuary resistance of \(1.346 \times 10^{-3}\) at the corresponding speed. The ship's residuary resistance in kN (in sea water of density 1025 kg/m\(^3\)), and the model speed in knots (round off to the nearest integer) respectively are

An oil tanker of breadth 20 m and having a displacement of 24000 tonnes in sea water (density of sea water = 1025 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. The apparent change in vertical center of gravity, due to the presence of oil in the tanks is .................... m (round off to one decimal place)

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 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. The longitudinal metacentric height is .................... m.

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 (\(A_{ij}\))?

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 ship moves at \(U = 9.81\ \text{m/s}\) in deep water. A wave is incident at an angle \(\beta = 120^\circ\). The encounter period measured onboard is \(4.187\ \text{s}\). Using \(g = 9.81\ \text{m/s}^2\), determine the actual wave period ____________ s (rounded off to one decimal place).