Class 1 (Chief Engineer) Engineering Management 📅 Jan 2025

Exam Question

What is parametric rolling of a ship? How is it originated? Under what consideration it has become important in today's scenario? Considering a post Panamax Container vessel carrying a load of 1300 containers is overtaken by a hailstorm. Enlist the effects on the ship due the condition under parametric rolling. Justify your answer with reasons. (16)

Reference Answer

### **1. Definition of Parametric Rolling**
Parametric rolling is a severe and dangerous resonant roll motion that can occur in specific sea conditions, even when the waves are not on the beam. It is not caused by the direct action of wave forces exciting roll, but rather by a periodic variation of the ship's stability (specifically, the metacentric height, GM). This phenomenon is termed 'parametric' because the parameter of the system's governing equation (stability, or the GZ curve) varies with time.
### **2. Origin and Mechanism of Parametric Rolling**
The phenomenon originates from a combination of three critical factors:

Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.

View plans Browse library

← Browse more questions

Prepare on Android — MeoMock on Google Play