Weathertight or watertight doors, explained
The Herald of Free Enterprise and the Titanic are just a few examples of how crucial watertight doors are for reducing ship vulnerability in cases of flooding. The lessons learned are:
- Crew preparedness – what should your crew be aware of?
- Management contribution – which actions could ship/shore management take, and
- Industry contribution – how can manufacturers, the class society and flag administration contribute to reducing the risk of incidents related to the operation of watertight doors?
A watertight door compromises several technical systems (structural, electrical, hydraulic and control), with many possible failure modes. And not to forget the doors are constantly subject to wear and tear. Likewise, efficient barrier management depends on procedures describing correct operation during voyage and in emergency situations. As well as procedures ensuring correct and efficient maintenance. Finally, there is the human element of crew and officers, their awareness of the involved risk and the knowledge and motivation to operate the system correctly during operation and in cases of emergency.
Everybody involved should know how to avoid the risk of power operated weathertight or watertight doors and keep the ship from capsizing or sinking.
Watertight doors
Water tight doors are designed to prevent water ingress from both sides, thereby ensuring that watertight integrity of the neighboring compartment of the ship is not lost. Watertight doors are located below deck level and are designed to open and close upwards or sideward (usually by automatic means). A remote signal on the status (open / close) of watertight doors is required by regulators.
A watertight ship door or hatch withstands a so-called ‘water column’ (water pressure) from both sides.
The closure between two compartments below the waterline will typically be watertight. It is essential that these compartments are resistant against great water pressure, as is the case during a major water leakage. Due to a watertight closure, the leakage won’t spread and the vessel will stay afloat. Because this watertight closure is so essential for the safety of the vessel, classification is required for in most cases.
The watertightness of a ship door or hatch is tested by mounting the door or hatch into a tank and applying a certain water pressure from the inside. If the water is coming from the outside of the door or hatch, the door leaf or hatch lid is pressed into the seal by the water pressure which helps to seal. Water coming from the inside, will counterwork. This way, the watertightness of a product can be easily measured.
Watertight doors keep the crew, passengers, installations and storage in the compartments, separated by wall or ceiling panels, safe and dry.
Weathertight Doors
Weather tight doors are located above the waterline of the vessel. Designed to prevent the entrance of water from outside to inside. This generally includes a insignificant head of water. Their main use is to prevent ingress of green seas, that is a solid wave of water coming aboard the deck of a ship, into the space of the ship they are designed to protect.
Most of the doors on deck are weathertight doors. These doors are designed to open outwards, thereby ensuring a positive pressure should there be a draught of water acting on them.
July Marine now offers a complete line of universal weather tight doors. These industry standard steel ship doors have been used on workboats, ships, and barges worldwide. See our list of references for the specifics of the vessels.
Available in three styles, four dog operating door, six dog operating door, and quick acting operating door. Various sizes available in each model. Please contact us for all available sizes.
A weathertight ship door or hatch is designed to withstand water pressure from the outside.
Typical locations where you will find weathertight closures are above the waterline, for example on the deck or in the wheelhouse of the ship. Weathertight doors or hatches are designed to withstand the weather conditions as found offshore. They can be submerged for a short period as would occur when hit by a standing wave.
Classification is, in most cases, not required as weathertight closures are generally tested with a high-pressure hose, which is directed at the seal. This test is also performed before the sea trial.
FLOOD DEFENSE SYSTEM
The weathertight doors are designed to be part of the vessel wide flood defense system. All doors come painted primer grey.
July Marine will produce the weathertight doors to your specific requirements, because an extensive number of options is available. As with all our ship access equipment, our weathertight doors are produced to the latest industry standards.
WEATHERTIGHT DOORS FEATURES
• Custom built to your specific requirements;
• Different material options available;
• Can be supplied with square or radiused edges;
• Hinged door design;
• Clip handle system operated from either side;
• Different window options available;
• Supplied to be compliant with industry standards.
