Exam Question
Define the following stating how they affect the ship structure and what component parts of the ship structure help to resist the effect:
(a) Racking (4)
(b) Panting (4)
(c) Pounding (4)
(d) Vibration from engine and propellers. (4)
Class 4 (4th Engineer)
SC&S
📅 May 2024
Reference Answer
This detailed response addresses the specified structural phenomena, their effects on the ship's structure, and the component parts designed to resist them, in line with "Surveyor-Grade" examination requirements.
### (a) Racking
* **Definition**: Racking refers to the transverse distortion or deformation of the ship's cross-section, particularly evident in the cargo holds or machinery spaces. It is a parallelogram-like deformation where the deck and bottom structures move horizontally relative to each other, while the sides remain relatively vertical, or vice-versa. This occurs primarily due to transverse forces such as wind pressure, wave impact on the ship's side, cargo shifting, or asymmetric loading, especially during rolling motions in a seaway.
* **Affects Ship Structure**: Racking causes shear stresses in the transverse bulkheads, decks, and bottom structure. The primary areas of concern are:
### (a) Racking
* **Definition**: Racking refers to the transverse distortion or deformation of the ship's cross-section, particularly evident in the cargo holds or machinery spaces. It is a parallelogram-like deformation where the deck and bottom structures move horizontally relative to each other, while the sides remain relatively vertical, or vice-versa. This occurs primarily due to transverse forces such as wind pressure, wave impact on the ship's side, cargo shifting, or asymmetric loading, especially during rolling motions in a seaway.
* **Affects Ship Structure**: Racking causes shear stresses in the transverse bulkheads, decks, and bottom structure. The primary areas of concern are:
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