Section 1 General

1.1.1 The requirements of this Chapter cover the transverse, longitudinal and horizontal boundaries of watertight compartments and deep tanks. Requirements are also given for non-watertight bulkheads. For bulkheads in the cargo compartment space of tankers, see the individual ship type Chapters in Pt 4 Ship Structures (Ship Types).

1.1.2 The requirements of this Chapter apply to vertically stiffened bulkheads. They may also be applied to horizontally stiffened bulkheads provided that equivalent end support is fitted and alignment provided.

1.2.1 All ships are to have a collision bulkhead, a watertight bulkhead at each end of the machinery space and an after peak bulkhead. In ships with the machinery space aft, the after peak bulkhead may form the after boundary of the machinery space. Where sterntubes are enclosed in a suitable watertight space, the after peak bulkhead may be omitted in ships as indicated in Pt 3, Ch 7, 1.4 After peak bulkhead 1.4.1. Additional bulkheads are to be fitted to provide for sufficient transverse strength of the vessel.

1.2.2 The bulkheads in the holds should be spaced at reasonably uniform intervals. Where non-uniform spacing is unavoidable and the length of a hold is unusually great, the transverse strength of the ship is to be maintained by fitting web frames, increased framing, etc. Details are to be submitted for approval.

1.2.3 For subdivision requirements within the cargo tank region of tankers, see individual ship type Chapters in Pt 4 Ship Structures (Ship Types).

1.2.4 Where applicable, the number and disposition of bulkheads are to be arranged to suit the requirements for subdivision, floodability and damage stability of the National Authority of the country in which the ship is to operate or be registered.

1.3.1 A collision bulkhead is to be arranged at a suitable distance from the forward perpendicular at a location that, when the fore peak is fully flooded, the buoyancy of the fully loaded vessel is sufficient and a residual safety distance of 100 mm from any opening which cannot be closed weathertight is attained.

1.3.2 As a general rule, the requirement of Pt 3, Ch 7, 1.3 Collision bulkhead 1.3.1 shall be considered to have been met if the collision bulkhead has been positioned at a distance between 0,04L and 0,04L + 2 m from the F.P. If the distance exceeds 0,04L + 2 m, compliance with Pt 3, Ch 7, 1.3 Collision bulkhead 1.3.1 shall be proven by direct calculations.

1.3.3 The distance from the F.P. may be reduced to 0,03L in which case the requirement of Pt 3, Ch 7, 1.3 Collision bulkhead 1.3.1 shall be proven by direct calculations based on the flooding of both fore peak and those compartments directly aft of and adjacent to the collision bulkhead.

1.3.4 Special designs or types of ships requiring another position, will be specially considered.

1.3.5 Doors, manholes, permanent access openings or ventilation ducts are not to be cut in the collision bulkhead below the uppermost continuous deck.

1.3.6 Any recesses or steps in collision bulkheads are to fall within the limits of bulkhead positions.

1.4.1 All ships are to have an after peak bulkhead generally enclosing the sterntube and the rudder trunk in a watertight compartment. An after peak bulkhead generally enclosing the sterntube and the rudder trunk in a watertight compartment is to be arranged at a suitable distance from the stern at a location at which, when the watertight compartment aft of the aft peak bulkhead is fully flooded, the buoyancy of the fully loaded vessel is sufficient, with a residual safety distance of 100 mm from any opening which cannot be closed weathertight is attained. This after peak bulkhead need not be fitted on ships with a length L less than 25 m if the stern tube is enclosed in a suitable watertight space. In ships with two or more propellers where the bossing ends forward of the after peak bulkhead, the sterntubes are to be enclosed in a suitable watertight space.

1.4.2 As a general rule, the requirements of Pt 3, Ch 7, 1.4 After peak bulkhead 1.4.1 shall be considered to have been met if the after peak bulkhead has been positioned at a distance between 0,04L and 0,04L + 2 m from the aft point of the intersection of the hull with the maximum draught line. If the distance exceeds 0,04L + 2 m, compliance with Pt 3, Ch 7, 1.4 After peak bulkhead 1.4.1 shall be proven by direct calculations.

1.4.3 The distance from the aft point of the intersection of the hull with the maximum draught line may be reduced to 0,04L − 1 m, in which case the requirement of Pt 3, Ch 7, 1.4 After peak bulkhead 1.4.1 shall be proven by direct calculations based on the flooding of both the compartment aft of the aft peak bulkhead and the immediately adjacent compartments.

1.5.1 All bulkheads are to extend to the uppermost continuous deck. In ships with continuous coamings the transverse hold bulkheads are to extend to the top of the coaming and are to be suitably stiffened at their top edge.

1.6.1 Cofferdams are required between each tank carrying:

1. Fuel oil or lubricating oil;

2. Feed water or fresh water; and

3. Vegetable or similar edible oils.

However, cofferdams need not be fitted between fuel oil or lubricating oil double bottom tanks and deep tanks carrying feed water, fresh water or vegetable or similar edible oils provided that the double bottom tanks are not interconnected with any tanks above.

1.6.2 Lubricating oil compartments are also to be separated by cofferdams from those carrying fuel oil. However these cofferdams need not be fitted provided that:

1. Common boundaries of lubricating oil and fuel oil tanks have full penetration welds.

2. The tanks are arranged such that the fuel oil tanks are not generally subjected to a head of oil in excess of that in the adjacent lubricating oil tanks.

1.6.3 Cofferdams are required between fuel oil double bottom tanks and deep tanks above when the double bottom tank and side tanks are interconnected.

1.7.1 Fuel oil, lubricating oil and hydraulic oil are not to be carried forward of the collision bulkhead.

1.7.2 Fuel tanks and their fittings shall not be located directly above engines or exhaust pipes.