Exam Question

### (a) Bilge Keel Design and Attachment for Shell Plate Protection (8 Marks)
The design and attachment of bilge keels are governed by classification society rules to maximize roll-damping effectiveness while minimizing the risk of shell plate damage in case of grounding or contact. The key features are:
* **Location and Profile**: Bilge keels are longitudinal fins fitted at the turn of the bilge, where the rolling motion has the greatest velocity. Crucially, they are designed to be within the moulded lines of the vessel's breadth and baseline, meaning they do not protrude beyond the side shell or below the keel. This protects them during docking and navigation in confined waters.
* **Reinforcing Doubler Plate**: The bilge keel itself is not welded directly to the main hull shell plating. Instead, a thick reinforcing plate, often called a 'doubler plate' or 'ground bar', is first continuously welded to the hull. This doubler plate is thicker than the shell plating and distributes the forces over a larger area.