Marine Staff: Collision Bulkhead vs. Watertight Bulkhead

Definitions

• Collision Bulkhead: A bulkhead designed to keep water away from the forward hold in case of bow collision damage.
• Watertight Bulkhead: A bulkhead that prevents water from passing through it, essential for ship safety.

Collision Bulkhead Characteristics

• Extends from the bottom of the hull to the freeboard deck, reaching the forecastle deck.
• Must be watertight from the bottom of the ship up to the bulkhead deck.
• Located in the forward part of the ship.

Location Regulations

• Every ship must have a collision bulkhead at a distance from the forward perpendicular:
  • 5% of the ship's length or 10m TRS, whichever is less.
  • Must not be more than 0.08 L or 0.05 L + 3m, whichever is greater.
• Positioning considerations:
  • Not too far forward to avoid damage on impact.
  • Not too far aft to prevent excessive trim by head when compartments flood.
  • Ideally located for maximum space for cargo.

Strength and Design

• Collision bulkhead is 20% stronger than other bulkheads.
• Generally located 5-8% of the ship's length from the forward perpendicular.
• Minimum distance required for effectiveness and cargo space maximization.

Additional Regulations Regarding Collision Bulkheads

1. Recesses and Steps: The collision bulkhead may have recesses or steps.
2. Pipes Piercing Bulkheads: Pipes piercing bulkheads must have valves operable from above the freeboard deck.
   • Valve chests must be secured to the bulkhead in the forepeak.
   • Valves may be installed after the collision bulkhead if easily accessible.
   • The space around the valves cannot be a cargo space.
3. No Openings: No doors, hatches, or any openings shall be fitted in the collision bulkhead.
4. Stiffeners: Stiffeners should be spaced 600 mm apart.
5. Tightness Testing: Tightness can be tested by:
   • Filling the forepeak tank to the water line level.
   • Conducting hose tests along the boundary.
   • Checking for leaks through other sides.
6. Compartment Division: The forepeak may be divided into two compartments designed to hold two different liquids.