Watertight doors

1) Describe the aid of a sketch a typical watertight door.

Water tight doors
There are three classes of water tight doors.
A) Hinged door
B) Hand operated sliding door.
C) Sliding doors that are powered operated and hand operated.
Features of water tight door
1) water tight doors are fitted on access openings on bulkheads.
2) Number of such openings are to be kept to a minimum compatible with design and as required for the safe working of the ship
3) if opening is on the bulkhead, the area to be framed and enforced to ensure the structural strength of the bulkhead is not compromised.
4) doors to be located outside damage zone of B/5.
5) Doorway to keep as small as possible.
6) Door controls to be kept as close as possible to the bulkhead.
7) Shall have both power and manual controls, both from the central control position and on either side of the door. (sliding door)
8) power operated doors must have indicators at the remote position (bulkhead deck or Nav Bridge)
9) Alarms when closed by power remotely (sliding door)
10) doors that cannot be closed from the central position must be closed before the voyage commences. Log entries to be made, fitted with a device that prevents illegal opening
11) Sliding doors can be able to close against an adverse list of 15 degrees.
12) uniform rate of closure, in upright position between 20 to 40 secs.
13) simultaneous closure from a central console, to be closed in 60s when ship is upright. (sliding type).
14) to be supplied by an emergency source of power.

2) State your understanding of the meaning of the terms “Door closed” and “Local control” and “Potentially hazardous situation” in relation to watertight doors.
Door control system (Door closed and Local control)
– Door control system should give efficient operation but reduce risk of injury to personnel to a minimum.
– Central control to have “Door closed” and “Local control”.
– “Door closed” is for emergency or drill use. Because of risk of injury to personnel. It must be preceded by an adequate warning signal.
Doors must automatically shut if opened locally, alarm to sound until door has shut.
– “Local control” is for normal use.
Potentially Hazardous situation
– Potentially hazardous situation is defined as a situation when a ship is navigating
1) very close to navigational hazards.
2) when there is restricted visibility
3) heavy traffic density
4) when depth of water is less than 3 times the draft of the vessel.

3) State your understanding of the following types of watertight doors.
A) Type A
B) Type B
C) Type C
Type A
– a door which may be left open.
Type B
– a door which should be closed, it may remain open only whilst personnel are working in the adjacent compartment.
Type C
– a door which should be closed.
– it may be opened for sufficient time to permit through passage.

4) State the ‘control’ requirements of watertight doors.
Door control system (Door closed and Local control)
– Door control system should give efficient operation but reduce risk of injury to personnel to a minimum.
– Central control to have “Door closed” and “Local control”.
– “Door closed” is for emergency or drill use. Because of risk of injury to personnel. It must be preceded by an adequate warning signal.
Doors must automatically shut if opened locally, alarm to sound until door has shut.
– “Local control” is for normal use.
Door operation
– doors to have two sources of power. (Normal and Emergency)
– hydraulic fluids to be non-freezing.
– door control to be operable from both side of the door and power control unit within reach of the door.

Speed of operation
– All power operated doors must be capable of being closed from the remote position within one minute.
– when being closed it must be accompanied by an audible alarm.
– doors must be closed promptly in an emergency to prevent progressive flooding potentially very hazardous, especially in Ro-Ro ships.
– doors should close at a uniform rate in not less than 20 secs, but not more than 40 secs when the ship is upright.

5) State the requirements in relation to the inspection and drills for watertight doors.
– all watertight doors fitted in the main transverse bulkheads, in use at sea, must be operated daily.
– all watertight doors and their mechanisms, indicators & valves, necessary to make a compartment watertight must be inspected at sea once a week.
– drills for the operating of watertight doors, side scuttles, valves and closing mechanisms must be held weekly.
– records of operations, inspections & drills are to be entered in the deck/engine log book along with record of any defects found.

6) Describe the three main classes of watertight doors.
Water tight doors
There are three classes of water tight doors.
A) Class 1- Hinged door
B) Class 2- Hand operated sliding door.
C) Class 3- Power operated and hand operated sliding door.
Class 1- Hinged door
– to be fitted with quick closing device, such as latches which can be operated from the both side of the bulkhead.
– it is only permitted to be fitted above a deck, the underside of which at its lowest point is at least 2 m above the deepest subdivision loadline.
Class 2- Hand operated sliding door
– it is required to have either a horizontal or vertical motion.
– the mechanism is to be operated above the bulkhead deck, with an all round crank motion.
– the time needed to close the door, when in upright position by hand gear is not to exceed 90 seconds.
Class 3- Power operated and hand operated sliding door
– shall have horizontal or vertical motion.
– if the door is powered operated from a control station, the gearing arrangement should also be provided for local power operation on both sides of the door and they are reachable by one person with the lever in the open position to prevent accidental setting of the closing mechanism.
– manual hand gear operation to be provided above the bulkhead deck and at both sides of the door in an accessible position.
– this gearing to be crank motion or other movement to maintain the same degree of safety.
– audible and visual warnings should be present when the doors is begun to close and will continue until the door has fully closed. Sufficient time is required to ensure safety.