Watertight and weather-tight doors

 

Watertight and weather-tight doors

Sourced and excerpted from 

1. Rules & Regulations for the Classification of Ships – LRS
2. SOLAS Consolidated 2014

Learning Objectives

After completing this topic you will be able to:

• Differentiate between the different categories of watertight doors
• Sketch and describe 

1. Arrangement of power operated watertight door
2. Hinged water tight door and means of securing them
3. Ramp doors
4. Ship side doors

• Differentiate between watertight and weather tight doors
• Know the rules regarding the number of opening in passenger ships and watertight doors
• Carry out routine inspections and maintenance and maintain records for the same
• Know the mandatory drills required for watertight openings and record keeping for the same.

 

 

Watertight Doors

Watertight Doors

Doors in the watertight bulkhead maintain watertight integrity. The frame of the watertight door has thicker plating and is heavier than the usual plating found on a bulkhead. Watertight doors are operated manually or remotely. Remotely controlled doors are operated from three locations.

1. Central
2. Remote
3. Local

Doors are operated simultaneously from the central control station. An indicator panel shows open or closed positions of five or more doors. Doors are also remotely operated from one deck above. Each door has a manual local control on either side of it. Watertight doors are classified as vertical and horizontal type sliding doors depending on the direction in which they are operated. The doors are operated either hydraulically or electrically.

Hydraulically operated watertight door

Hydraulic operation of the watertight door is carried out by a local or remote hand pump.

The following media explains the components and the operation of hydraulically operated watertight doors.

Hydraulically Operated Watertight Doors

 

 

 

 

 

Watertight door

Vertically mounted watertight door

Water Tight Doors:

To allow the passage for personnel water tight doors are fitted , openings must be cut only were essential and they should be as small as possible. 1.4m high, 0.7m wide being the usual.

Doors should be of mild steel or cast steel, and they may be arranged to close vertically or horizontally.

The closing action must be positive i.e. it must not rely on gravity. Hinged water tight doors may be allowed in passenger ships and in watertight bulkheads above decks which are placed 2.2m or more above the waterline. Similar doors may be fitted in weather decks openings in cargo ships

Hinged water tight door

 

Hinged water tight doors consist of a heavy section door which when closed seals on a resilient packing mounted in channel bar welded to the door frame. The door is held firmly in the door frame when closed by the dogging arrangements shown which allow the doors to be opened from either side. Normally six of these dogs are spread equally around the periphery.

Automatic watertight operating gear

Operating of Water Tight Doors:

Automatic operating gear allows the remote operation of watertight doors. These are fitted on many vessels including passenger ships.

In the event of fire or flooding, operation of switches from bridge/fire control area sends a signal to an oil diverter valve. Oil from a pressurised hydraulic system is sent to a ram moving the door.

The door may also be operated locally by a manual diverter valve. In addition, in the event of loss of system pressure the door may be operated by a local manual hand pump remote door position indicators are fitted as well as were appropriate alarms to indicate operation

W/T doors, mechanisms, indicators and all associated valves must be inspected once in a week

Inspection, Maintenance, Drills and Record keeping

(SOLAS Chapter II-I, Part B-4, Regulation 21 & 22)

Inspection and Maintenance

The watertight doors and all mechanisms and indicators connected therewith, all valves the closing of which is necessary to make a compartment watertight, and all valves the operation of which is necessarily for damage control cross-connections shall be periodically inspected at sea at least once a week.

The following media explains about the Door operating Hydraulic cylinder:

The following media explains about the Features of weather tight and watertight door

The following media explains about the Types of watertight door

The following media explains about the Operation of watertight doors

The following media explains about the necessities of the watertight door top keep in closes mode at sea

The following media explains about the safety precautions to be taken while operating the doors

The following media explains about the maintenance of watertight doors

 

 

All W/T doors in main transverse bulkhead must be operated daily

All watertight doors, both hinged and power-operated, in watertight bulkheads, in use at sea, shall be operated daily.

 

Drills for operating W/T doors, side scuttles, valves  and closing mechanism must be held weekly

Drills

Drills for the operating of watertight doors, side scuttles, valves and closing mechanisms of scuppers, ash-chutes and rubbish-chutes shall take place weekly. In ships in which the voyage exceeds one week in duration a complete drill shall be held before Leaving port, and others thereafter at least once a week during the voyage.

 

Records of drills and inspections to be entered in log book with regard to defects

Records

• The master shall ensure, before the ship proceeds on any voyage, that an entry in the logbook is made of the time of the last closing of the doors, RO RO decks, side ramps and side scuttles which are required to be closed during navigation, and the time of any opening of particular doors which are allowed to be opened at sea.
• A record of all drills and inspections required by this regulation shall be entered in the logbook with an explicit record of any defects which may be disclosed.

Categories of Watertight Doors

General Categories:

• Class 1 — Hinged doors 
• Class 2 — Hand-opened sliding doors 
• Class 3 — Sliding doors which are power-operated as well as hand-operated 

Operational Categories (LRS)

 

Category	Definition	Open While at sea
A	A watertight door that fulfils the technical requirements in SOLAS regulations II- 1/13.5.1 to 13.5.3 and 13.6 which also includes the requirements in paragraph 7 of SOLAS regulation II-1/13,	The door is permitted to remain open during navigation by the Administration according to SOLAS regulation II-1/22.4
B	A watertight door that fulfils the technical requirements in SOLAS regulations II- 1/13.5.1 to 13.5.3 and 13.6 which also includes the requirements in paragraph 7 of SOLAS regulation II-1/13	The door may be opened during navigation when work in the immediate vicinity of the door necessitates it being opened, according to SOLAS regulation II- 1/22.3. The door must be immediately closed when the task which necessitated it being open is finished.
C	A watertight door that fulfils the technical requirements in SOLAS regulations II- 1/13.5.1 to 13.5.3 and 13.6 ,which also includes the requirements in paragraph 7 of SOLAS regulation II-1/13.	The door may be opened during navigation to permit the passage of passengers or crew, according to SOLAS regulation II-1/22.3. The door must be immediately closed when transit through the door is complete.
D	A watertight door that does not comply with SOLAS regulations II-1/13.5.1 to 13.5.3 and 13.6, which also includes the requirements in paragraph 7 of SOLAS regulation II-1/13	The door shall be closed before the voyage commences and shall be kept closed during navigation according to SOLAS regulation II-1/22.1.   ((Currently, doors of category D do not comply with the requirements relating to WTD, and therefore, such doors need to be closed before leaving port. Doors with this new category are now defined to be closed during normal operation, they are not even opened for passage, but they are only used as secondary means of escape. They will comply with the other requirements for WTD as stated in regulation II-1/13.))   ((To prevent any unintended use, any opening of the door should cause a fire alarm.))

 

 

Rules regarding the number of openings on passenger ships and watertight doors

Opening in Passenger Ships and Watertight Doors

In this section openings in the Bow, Shell abaft the collision bulkhead, enclosed superstructures, stern and below freeboard decks are considered, and the all important closing devices these openings require for maintaining the vessels seaworthiness.

Watertight doors should be able to be closed with the ship listed 15 degrees on either side.

Bow

Considering the importance and sensitivity of this part of the vessel it is treated separately.

• Bow doors are to be situated above the freeboard deck. A watertight recess in the freeboard deck located forward of the collision bulkhead and above the deepest waterline, fitted for arrangement of ramps or other related mechanical devices, may be regarded as a part of the freeboard deck for the purpose of this requirement.
• Where bow doors lead to a complete or long forward enclosed superstructure, or to a long non-enclosed superstructure which is fitted to attain minimum bow height equivalence, an inner door is to be fitted. The inner door is to be part of the collision bulkhead. 
• Where a sloping vehicle ramp forming the collision bulkhead above the freeboard deck is arranged, the inner door may be omitted if the ramp is weather tight over its complete length and fulfils requirements of Structural Design concerning the position of the collision bulkhead.
• Bow doors are to be fitted with arrangement for ensuring weather tight sealing, such as gaskets, and to give effective protection to inner doors.
• Inner doors forming part of the collision bulkhead are to be watertight over the full height of the cargo space and arranged with fixed sealing supports on the aft side of the doors.
• Bow doors and inner doors are to be arranged so as to preclude the possibility of the bow door causing structural damage to the inner door or to the collision bulkhead in the case of damage to or detachment of the bow door. If this is not possible, a second separate inner weather tight door is to be installed.
• The requirements for inner doors are based on the assumption that vehicles and cargo are effectively lashed and secured against movement from the stowed position.

Openings in  Shell abaft the collision bulkhead, enclosed superstructures, stern and below freeboard decks 

• Stern and shell side: Doors which ensure the structural strength and water tightness that the particular area requires. The strength should be at least equivalent to the area where the opening is situated
• Except for the pilot boarding door which is allowed to open inward, all other doors below the freeboard deck will open outward. If they open inwards additional securing devices are required.
• Weather tight doors are to open outwards
• Inward opening doors if situated between the 1st two tween decks above the summer load line are to be fitted with a second independent securing device.

Additional for Passenger vessels

• Lower edge of door openings is not to be below a line drawn parallel to the loadline.
• To the freeboard deck at side, which has at its lowest point at least 230 mm above the upper edge of the uppermost Load Line i.e. Tropical Fresh or if fitted Timber Tropical Fresh.
• Openings for Cargo, Access arrangements and service, situated below the margin line are to have the same strength requirements as side shell doors. Securing devices should effectively secure them watertight, and fail safe arrangements should be provided to ensure that they are closed before sailing and remain closed at sea. The lowest point should not be below the deepest subdivision load line.
• Where the inboard end of a rubbish chute is below the margin line, the inboard end cover is to be watertight and, in addition to the discharge flap interlock, a screw down automatic non-return valve is to be fitted in an easily accessible position above the deepest subdivision. The valve is to be controlled from a position above the bulkhead deck and provided with an open/shut indicator, and kept closed when not in use. A suitable notice is to be displayed at the valve position.

 

 

Difference between water tight and weather tight doors

Watertight and Weather tight Doors

Weather tight

A door is considered weather tight if it is designed to prevent the passage of water into the ship in any sea condition. I.e. Unidirectional

Generally, all openings in the freeboard deck and in enclosed superstructures are to be provided with weather tight doors and closing appliances.

Watertight

A door is considered watertight if it is designed to prevent the passage of water in either direction under the pressure of a head of water for which the surrounding structure is designed.

Generally, all openings below the freeboard deck in the outer shell and in bulkheads that terminate at the bulkhead deck are to be fitted with permanent watertight closing devices.

Arrangement of Power operated sliding W/T door

Power Operated Watertight Door

The following media explains about the Door operating the Hydraulic cylinder

Excepts from SOLAS

5.1 Watertight doors, except as provided in paragraph 9.1 or regulation 14, shall be power-operated sliding doors complying with the requirements of paragraph 7 capable of being closed simultaneously from the central operating console at the navigation bridge in not more than 60 s with the ship in the upright position.

5.2 The means of operation, whether by power or by hand, of any power-operated sliding watertight door shall be capable of closing the door with the ship listed to '15'either way. Consideration shall also be given to the forces which may act on either side of the door as may be experienced when water is flowing through the opening, applying a static head equivalent to a water height of at Least 1 m above the sill on the centerline of the door.

5.3 Watertight door controls, including hydraulic piping and electric cables, shall be kept as close as practicable to the bulkhead in which the doors are fitted, in order to minimize the Likelihood of them being involved in any damage which the ship may sustain. The positioning of watertight doors and their controls shall be such that if the ship sustains damage within one fifth of the breadth of the ship, as defined in regulation 2, such distance being measured at right angles to the centreline at the level of the deepest subdivision draught, the operation of the watertight doors clear of the damaged portion of the ship is not impaired.

6 All power-operated sliding watertight doors shall be provided with means of indication which will show at all remote operating positions whether the doors are open or closed. Remote operating positions shall only be at the navigation bridge as required by paragraph 7.1.5 and at the location where hand operation above the bulkhead deck is required by paragraph 7.1.4.

6.1 If the Administration is satisfied that such doors are essential, watertight doors of satisfactory construction may be fitted in watertight bulkheads dividing cargo between deck spaces. Such doors may be hinged, rolling or sliding doors but shall not be remotely controlled. They shall be fitted at the highest, level and as far from the shell plating as practicable, but in no case shall the outboard vertical edges be situated at a distance from the shell plating which is less than one fifth of the breadth of the ship, as defined in Regulation 2, such distance being measured at right angles to the centerline at the level of the deepest sub division draught.

 

 

 

Hinged W/T door and means of securing

Hinged Watertight Door

Closing and Securing Arrangements

• Bow doors are to be fitted with adequate means of closing, securing and supporting so as to be commensurate with the strength and stiffness of the surrounding structure. The hull supporting structure in way of the bow doors is to be suitable for the same design loads and design stresses as the securing and supporting devices. Packing material is to be of a comparatively soft type, and the supporting forces are to be carried by the steel structure only. Maximum design clearance between securing and supporting devices is not to exceed 3 mm.
• Securing devices are to be simple to operate and easily accessible. They are to be of a design approved by Class for the intended purpose.
• Securing devices are to be equipped with positive locking arrangements. Arrangements are to be such that the devices are retained in the closed position within design limits of inclination, vibration and other motion-induced loads and in the event of loss of any actuating power supply.
• Systems for door opening/closing and securing/locking are to be interlocked in such a way that they can only operate in a proper sequence. Hydraulic systems are to comply with Class requirements
• Means are to be provided to enable the bow doors to be mechanically fixed in the open position taking into account the self-weight of the door and a minimum wind pressure of 1,5 kN/m² (0,153 tonne-f/m²) acting on the maximum projected area in the open position.
• The spacing for side and top cleats should not exceed 2,5 m and there should be cleats positioned as close to the corners as practicable. Alternative arrangements for ensuring weather tight sealing will be specially considered.
• Control and monitoring arrangements are to comply with SOLAS.

Definition of Securing, Locking  device

• A mechanical device which keeps the door closed and prevents it pivoting/ rotating about its hinges.
• A locking device locks a door’s securing device in the closed position
  

 

Ramp door of Ro-Ro ships

RORO Ship with various types of watertight doors

 

 

Ship side doors

The following media explains about the door animation speed