Hotel Service Unit 19 Definitions Q7 Answer

  1. Explain EACH of the following types of motion:
    (a) roll;(2)
    (b) pitch;(2)
    (c) yaw;(2)
    (d) surge;(2)
    (e) heave.(2)

(a) Roll (2 marks)

  • Meaning: The side-to-side tilting motion of a vessel about its longitudinal axis (fore-and-aft axis).
  • Cause: Waves or wind pressure acting on the vessel’s sides.
  • Effect: Affects stability and crew comfort.

(b) Pitch (2 marks)

  • Meaning: The up-and-down tilting of the vessel’s bow and stern about the transverse axis (athwartships axis).
  • Cause: Encountering head seas or stern seas.
  • Effect: Can cause slamming, increased resistance, and discomfort.

(c) Yaw (2 marks)

  • Meaning: The side-to-side swinging of the vessel’s bow about the vertical axis.
  • Cause: Following seas, rudder action, or uneven loading.
  • Effect: Affects course-keeping and steering stability.

(d) Surge (2 marks)

  • Meaning: The longitudinal forward and backward motion of the vessel along its fore-and-aft axis.
  • Cause: Wave action or sudden changes in engine thrust.
  • Effect: Impacts propulsion efficiency and causes fluctuating propeller loads.

(e) Heave (2 marks)

  • Meaning: The vertical up-and-down motion of the vessel along its vertical axis.
  • Cause: Passage of waves beneath the hull.
  • Effect: Affects comfort and can cause cargo shift or pounding in heavy seas.