NAV 1 QUIZ 2 2025 MIDTERM

Why does deviation happen in a ship’s magnetic compass?

• Because of Earth’s magnetic field alone

• Because of the ship’s permanent and induced magnetism

• Because of chart projection errors

• Because of gyro errors

How does a ship’s own magnetism affect the readings of its magnetic compass?

• By altering the ship’s speed

• By deflecting the compass needle from Magnetic North

• By changing the variation angle

• By aligning the compass with True North

What does it indicate if a ship’s compass error changes as the ship’s heading changes?

• The compass is affected by variation.

• The error is caused by deviation.

• The ship is at the magnetic equator.

• The compass card is misaligned.

How does Earth’s magnetic field cause induced magnetism in a ship’s steel hull?

• It permanently magnetizes the hull.

• It temporarily magnetizes the hull in Earth’s field

• It changes the compass graduation.

• It eliminates all deviation.

How can ship’s heading, cargo, and magnetic latitude influence compass deviation?

• They affect the compass card’s material.

• They change magnetic forces on the compass

• They reduce variation.

• They have no effect on deviation.

Why are compass correctors like soft iron spheres and a Flinders bar used on ships?

• To align the compass with True North.

• To minimize deviation by balancing magnetic forces

• To measure magnetic dip.

• To calculate variation more accurately

Why does a ship often experience a change in deviation after being in dry dock for a long time?

• Because permanent magnetism in the hull changes.

• Because variation decreases.

• Because the compass loses sensitivity.

• Because cargo weight increases.

How does wrong phase setting affect echo-sounder accuracy?

• It disables the stylus motor unit

• It causes incorrect timing of pulses

• It increases the chart scale error

• It removes all shallow water clutter

What is the effect of velocity changes in water on depth readings?

• Depth readings become inconsistent

• Stylus speed increases automatically

• Transducer signal becomes distorted

• Display unit resets chart scale

How does the echo-sounder convert sound into visual depth data?

• Gain control adjusts signal strength

• Stylus burns through chart paper

• Echoes are processed and displayed

• Transducer emits continuous pulses