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25-Nav-A3 Hydrodynamics of Ships (II)_ Ship Motion: December 2019

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

  1. Question 1 Definitions in Ship Dynamics
  2. Question 2 Water Depth, Wave Height and Wavelength from Two Pressure Sensors
  3. Question 3 Rolling Magnification Factor and Maximum Roll Amplitude
  4. Question 4 Irregular Seaway — Wave Energy, Significant Heave, Significant Vertical Acceleration
  5. Question 5 Froude-Krylov Wave-Exciting Force and Moment on a Box Barge
  6. Question 6 Choice of (a) Hydrodynamic-Derivative Classification or (b) Steady Turning Radius

Start with Question 1 →

National Exams — December 2019 — 16-Nav-A3 Hydrodynamics of Ships (II): Ship Motion. Three-hour, closed-book exam; one two-sided 8.5″×11″ formula sheet and an approved calculator are permitted. Format: Questions 1–5 are compulsory; Question 6 offers a choice of (a) or (b) — both are solved below for completeness.

Reference texts: Bhattacharyya, Dynamics of Marine Vehicles (Wiley) — wave kinematics/pressure, roll response and magnification-factor theory, irregular-seaway spectral analysis; Lewis (ed.), Principles of Naval Architecture, Vol. III — Motions in Waves and Controllability (SNAME) — Froude-Krylov theory, added mass, hydroelasticity, linear maneuvering derivatives; Lloyd, Seakeeping: Ship Behaviour in Rough Weather — roll magnification factor and encounter-frequency spectra; Lewandowski, The Dynamics of Marine Craft — the prime-system nondimensional maneuvering equations used in Question 6(b).

In Question 2, sensor 2's dynamic pressure amplitude is 25,600 N/m², the value used throughout (it gives a water depth of about 10.0 m).