GB2299790A

GB2299790A - Ferry Safety System

Info

Publication number: GB2299790A
Application number: GB9507642A
Authority: GB
Inventors: Alan Robert Johnston
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-04-12
Filing date: 1995-04-12
Publication date: 1996-10-16
Also published as: GB9507642D0

Abstract

A roll-on roll-off ferry safety system comprises a plurality of interconnected water catchment tanks provided beneath the cargo deck, with drainage means being provided between the cargo deck and the catchment tanks,flow restraint means and water distribution means for even distribution of ingress water, pump means for expelling water from the water catchment tanks, and alarm means for indicating ingress of water to a predetermined level in the tanks.The drainage means comprises apertures in the floor of the deck, and the tanks may be arranged in longitudinal rows parallel to the ships length or in matrix form.The water flow restraint means comprise vertical baffles in the tanks.

Description

Device for Water Ingress Management This invention relates to a device for water ingress management on roll-on roll-off ferries and in particular to a device for use in cargo deck water ingress management on roll-on roll-off ferries.

Roll-on roll-off ferries have the inherent problem of unwanted sea water entering the cargo deck for example if the bow doors are not correctly shut. The entry of unwanted water into the cargo deck, especially whilst the ferry is sailing, drastically reduces the stability of the ferry.

Subsequent displacement (whilst sailing) of the water held in the cargo deck need not be large before capsize of the ferry may result. The speed and quantity of the water entering the cargo deck in this situation makes removal of the water a difficult task.

The aim of the present invention is to provide a device for use in cargo deck water ingress management on roll-on roll-off ferries which obviates or mitigates the aforementioned disadvantages.

According to this invention there is provided a device for use in cargo deck water ingress management on roll-on roll-off ferries which comprises a plurality of interconnected water catchment tanks provided beneath a cargo deck, drainage means being provided between the cargo deck and the catchment tanks, flow restraint means and water distribution means for even distribution of ingress water, pump means for expelling water from the water catchment tanks, and alarm means for indicating ingress of water to a predetermined level in the tanks.

Preferably the tanks are arranged in longitudinal rows, parallel to the ships length.

Alternatively smaller tanks are arranged in matrix form.

Alternatively one large water catchment tank may be used.

This invention will now be described below, by way of example only with reference to the accompanying drawings which illustrate one specific embodiment only.

Figure 1 is a plan view of the water catchment area in which the tanks are arranged in the form of longitudinal rows which lie parallel to the ships length.

Figure 2 is a plan view of the water catchment area in which smaller tanks are arranged in matrix form.

A device for cargo deck water ingress management on roll-on roll-off ferries as shown in the figures comprises a horizontally suspended and substantially flat, elongate floor member of substantially the same dimensions as the cargo deck. The floor member can be formed of any suitable material and has apertures therethrough at equidistant intervals to allow drainage of ingress water.

Beneath the floor member is situated a plurality of water catchment tanks of a substantially rectangular shape which are made from any suitable material but generally a material of a non corrosive nature or a corrosive material which has been treated to resist or inhibit corrosion.

These tanks are arranged in such a way as to form longitudinal rows which lie parallel to the ships length.

Furthermore these water catchment tanks have a water distribution system which is in the form of interconnecting pipes.

These pipes are hollow, elongate tubes made from any suitable non corrosive material and are situated just below the overflow level of the tank and connect one water catchment tank to another thus allowing water to pass from one tank to another. These pipes are of a reasonably small diameter.

A hydraulic pump is provided which is connected via suitable circuitry to a suitable power source to expel water from the water catchment tanks to the surrounding sea water.

An audible alarm system and surveillance cameras are located within the area of the water catchment tanks the purpose of which will be explained below.

A water flow restraint system is provided which is in the form of a partial height, plate or baffle which is vertically upstanding from the floor of the tanks and are generally situated longitudinally down the centre of each water catchment tank.

In an alternative embodiment the longitudinally placed water catchment tanks are replaced by a matrix of smaller tanks running both parallel to and at right angles to the ships length. Even distribution of water is achieved by perforations in the common tank and dividing vertical walls and by making the dividing vertical walls of various heights which also restricts the flow of water so that stability of the ship is not unduly affected by movement of water between one sector of the ship to another.

In use of the present invention when sea water enters the cargo deck it is drained therefrom by the apertures in the floor member thus directing the water away from the cargo deck and into the water catchment tanks held beneath the cargo deck.

The water catchment tanks are all linked via the interconnecting pipes or perforated dividing walls so that if the water level in one tank increases dramatically the excess water will flow freely into another tank through these interconnecting pipes or perforated dividing walls therefore as each tank fills up the interconnecting pipes will ensure even distribution of the water throughout the tanks. In this way the water level of the tanks can be kept balanced to prevent uneven distribution of the water in the ship which would otherwise lead to instability of the ferry and may result in extreme cases with the ferry capsizing.

Once water enters the water catchment tanks an audible alarm will sound to alert the ferry crew to the fact that water has entered the cargo deck. There are also surveillance cameras situated in the water catchment area so that when the crew hear the alarm they can monitor the quantity of water which has already entered the water catchment area and also the speed with which the water is entering the catchment area.

The operator can then decide on the basis of the information gathered from viewing the surveillance cameras whether to hold the water in the tanks or whether to operate the hydraulic pump which will expel the unwanted water from the water catchment tanks back into the surrounding sea.

Furthermore, the water pumps may be set to activate automatically when water in the tanks rises to a predetermined level.

One advantage of this invention is that the water catchment tanks themselves are interconnected either by pipes or perforated dividing walls so that if there is a sudden large influx of water it will be equally distributed amongst the tanks. As mentioned above this is achieved by the placement of interconnecting pipes just below the overflow level of the tank. This distribution of the water therefore prevents reduction in the stability of the ferry which is what would normally occur if large amounts of unwanted water entered the cargo deck.

The stability of the ferry is also increased by the incorporation of baffles within the tank. This restricts the movement of the water in the tank whilst the ferry is in motion.

It is envisaged that the invention could be used with either a false or raised floor or only with water catchment tanks underneath one floor skin. The invention can be incorporated as an integral part of the design of a new ship, or retrofitted to an existing ship.

The foregoing invention allows a ferry which admits unwanted ingressed water within the cargo deck to minimise the instability and effects of ingress water which would otherwise affect the ferry, so that the affected ferry may remain stable for a longer period of time which may be enough to safely reach port or other destinations without sinking or capsizing.

Claims

1. A device for use in cargo deck water ingress management on roll-on roll-off ferries which comprises a water catchment tank provided beneath a cargo deck, drainage means being provided between the cargo deck and the catchment tank, flow restraint means, pump means for expelling water from the water catchment tank, and alarm means for indicating ingress of water to a predetermined level in the tank.

2. A device for use in cargo deck water ingress management on roll-on roll-off ferries which comprises a plurality of interconnected water catchment tanks provided beneath a cargo deck, drainage means being provided between the cargo deck and the catchment tanks, flow restraint means and water distribution means for even distribution of ingress water between the tanks, pump means for expelling water from the water catchment tanks, and alarm means for indicating ingress of water to a predetermined level in the tanks.

3. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to claim 1 or 2 wherein the drainage means comprises apertures in the floor of the cargo deck.

4. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to claims 2 or 3 wherein the water catchment tanks are arranged in longitudinal rows, parallel to the ships length.

5. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to claim 2 or 3 wherein the water catchment tanks are arranged in matrix form.

6. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to any one of the preceding claims wherein the tank(s) are made of a non corrosive material.

7. A device for use in cargo deck water ingress management on roll on roll off ferries according to any one of claims 2-5 wherein the water distribution system comprises a plurality of interconnecting pipes between the water catchment tanks.

8. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to any one of claims 2-6 wherein the water distribution system comprises a plurality of perforations in the dividing walls of the tanks to allow even distribution of ingress water in the tanks.

9. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to any one of claims 2-8 wherein the dividing walls of the water catchment tanks have various heights to restrict the flow of the water.

10. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to any one of claims 1-8 wherein the water flow restraint means comprises partial height plates or baffles vertically upstanding from the floor of the tank(s).

11. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to claim 10 wherein the plates or baffles are situated longitudinally down the centre of the water catchment tank(s).

12. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to any one of the preceding claims wherein the pump means is a hydraulic pump.

13. A device for use in cargo deck water ingress management on roll-on roll-off ferries according to any one of the preceding claims wherein the alarm means comprises an audible alarm and surveillance camera system.