WO2006021770A1

WO2006021770A1 - Method and apparatus for increasing the safety of ships

Info

Publication number: WO2006021770A1
Application number: PCT/GB2005/003272
Authority: WO
Inventors: Gordon Fraser; Donald Macleman
Original assignee: Gordon Fraser; Donald Macleman
Priority date: 2004-08-24
Filing date: 2005-08-23
Publication date: 2006-03-02
Also published as: GB0418802D0; GB2431902B; GB0704428D0; GB2431902A

Abstract

A gas expulsion apparatus suitable for installation into a vessel is disclosed. The apparatus comprises a device having a gaseous inlet (24) and a gaseous outlet (26), wherein the outlet is adapted to direct gas into a compartment (16) of a vessel (10). In a preferred embodiment exhaust gas from the vessel's engine is directed into an otherwise sealed compartment of a vessel in order to delay or reverse water ingress or to extinguish a fire. An advantage of certain embodiments of the invention is that they can stabilize stricken vessels. Moreover for certain embodiments of the invention where the vessel's engine is used to direct the gas, additional heavy and bulky equipment, which may be difficult to house on a vessel, is kept to a minimum.

Description

METHOD AND APPARATUS FOR INCREASING THE SAFETY OF SHIPS

This invention relates to a method and apparatus for delaying or reversing water ingress into a vessel and also or alternatively for extinguishing fire on board a vessel.

Vessels can be damaged at sea in a number of ways including collision, running aground, sea cocks breaking loose due to corrosion, or bridge windows being broken in heavy weather.

This can quickly result in engine failure if water is drawn into the engine's air intake. Continued ingress of water will inevitably lead to the vessel sinking.

Various solutions have been proposed to stabilise sinking vessels. In one proposed solution, large inflatable containers are placed alongside the vessel and attached thereto to provide additional buoyancy to the vessel. However, in practice these can be torn away from the vessel in poor weather and it is frequently during such poor weather when vessels are damaged and require stabilisation.

In Japanese Patent Application, publication number JP2003137177A a bag is provided which can be inflated by a cylinder to resist water ingress and provide some buoyancy. However the system requires many electrical switches and connections to sense water ingress and also to activate the bags whereas electrical connections are preferably minimised on board vessels. Moreover the system would requires frequent checks and maintenance to ensure the bags and accompanying cylinders are in working order. Lastly it appears that any person present when the bag was activated would be trapped by the inflation of the bag and so such a system may pose serious safety risks.

Bilge pumps are provided on vessels to pump away water but these are only designed to deal with very small volumes of water resulting from rain, sea spray, caught fish, washing down parts of the vessel or from melted ice and are not designed to nor are capable of pumping a volume of water encountered when, for example, the hull is punctured.

Fire is also a hazard on vessels and can be tackled in conventional manner by the use of fire extinguishers, COa gas or foam for example. However, for larger fires this may not be adequate and the vessel may be lost. According to a first aspect of the present invention there is provided a gas expulsion apparatus for a vessel, the apparatus comprising a device having a gaseous inlet and a gaseous outlet, wherein the outlet is adapted to direct gas into a compartment of a vessel.

Preferably the apparatus comprises a valve and tubing means which is adapted to direct gas from the gaseous outlet to any one or a combination of different compartments of the vessel.

Preferably the apparatus is adapted for use in a floating vessel.

Preferably the device is also adapted to power the movement of the vessel. Preferably therefore the device is an engine.

Preferably the valve and tubing means, in use, selectively directs gas from the gaseous outlet to one of an exhaust and a compartment of the vessel.

More preferably the valve and tubing means, in use, selectively directs gas from the gaseous outlet to one of (i) the exhaust and (ii) any one or a combination of different compartments of the vessel.

Preferably the apparatus comprises a plurality of conduits extending from preferably each of the respective compartments of the vessel and the conduits are preferably directed to the side of the vessel. Therefore, said conduits are preferably adapted, in use, to transfer water from the compartments of the vessel out of the vessel.

Preferably the conduits extend proximate to the bottom of the respective compartment to a height which is preferably above deck level. Preferably non-return valves are provided on each conduit to prevent water ingress into the compartments via said conduits.

Preferably the compartments of the vessel are watertight compartments. However, in an emergency, the compartments may be damaged and therefore punctured and therefore not watertight.

Preferably the gaseous inlet is above a main deck of the vessel. More preferably the gaseous inlet is provided on a portion of the vessel which is above the main deck, such as a chimney.

Preferably the gaseous inlet is an air inlet.

The invention also provides a vessel having an engine and an air intake for said engine above the level of a main deck of the vessel.

According to a further aspect of the present invention there is provided a vessel having a gas expulsion apparatus according to the first aspect of the present invention. According to a yet further aspect of the present invention, there is provided a method of delaying or reversing water ingress into a vessel, the method comprising blowing gas into a compartment of a vessel, and at least one of: (i) expelling water from said compartment of said vessel out of the vessel; or, (ii) reducing the rate of water ingress into the compartment of the vessel.

Preferably the method of the yet further aspect of the invention is performed using the apparatus according to the first aspect of the invention.

Preferably the method expels water from said compartment of said vessel out of said vessel.

Preferably the gas is exhaust gas from the engine of the vessel.

The invention also provides a method to extinguish a fire in a compartment of a vessel, the method comprising directing exhaust gas into said compartment.

Preferably the method is used for a vessel which is at least partially above the water line.

Preferably the air intake is provided above the deck, for example on a chimney. Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-

Fig. Ia is a side, partly sectional, view of a fishing vessel including apparatus according to the present invention; Fig. Ib is a front view of the Fig. Ia fishing vessel; Fig. Ic is a top view of the Fig. Ia fishing vessel; Fig. Id is an end view of the Fig. Ia fishing vessel; Fig. 2 is a diagrammatic view of a testing apparatus to determine the exit pressure of gas released from an engine; Figs. 3a and 3b are diagrammatic sketches of a box used to demonstrate the test for extinguishing the fires using exhaust gas of an engine; Fig. 4 is a graph showing the increase in pressure over time as water and air are fed into a sealed container.

Fig. Ia shows a fishing vessel 10 which comprises a number of compartments including a bridge 11, crew quarters 12, an engine room 14, forecastle 15 and a fish room 16; all of which are standard in the industry. The engine room 14 and the fish room 16 are typically provided at the bottom of the vessel 10, beneath the water line 18. Most of the various compartments can be sealed air-tight from one another and there can be more than one compartment for the crew and/or to hold the caught fish. Each such compartment can usually be independently sealed from the others.

An engine 20 provided in the engine room 14 and has an air intake 22 which is releasably connected to a conduit 24 to allow for access to replace filters (not shown) or other maintenance via a watertight door (not shown) .

The . conduit 24 extends from the air inlet 22 of the engine 20 to a chimney 26 or any other high and relatively sheltered point of the fishing vessel 10. Preferably the conduit 24 extends to the highest practical point on the vessel. Where the conduit extends to the chimney it is directed away from the exhaust outlet and provided as close to the centre line as possible. Other secondary engines (not shown) may also be provided and connected to the conduit 24 as described for the engine 20. The engine 20 can therefore still run if the engine room floods since the air for the engine is received through the conduit 24 which is not submerged at its other end.

A valve (not shown) at the conduit 24 of the engine 20 is provided at the highest point in the engine room 14 to allow air to be taken from the engine room 14 under normal operating conditions and then switched to take air from the atmosphere via the full length of the air inlet conduit 24 in an emergency situation. This ventilates the engine room 14 by allowing continuous circulation of air from the atmosphere through the engine and out through the exhaust. This prevents overheating in the engine room 14 due to the heat given off by the engine under normal operating conditions.

Vents (not shown) may also be provided in the engine room 14 and are adapted to close in an emergency situation to provide an airtight engine room 14.

The air outlet 32 of the engine 20 is connected to a conduit 34 which extends via standard and fine adjustment valves (not shown) to the chimney 26 to release exhaust gas fumes therefrom.

The exhaust gas outlet is also connected through a series of further lagged conduits 34, shown in Fig. Ic, to all compartments of the vessel, such as the fish room 16, crew quarters 12, and companionways (not shown) . (Lagged conduits are adapted to reduce transmission of heat.) Valves (not shown) are provided which can direct the exhaust gas through the conduit 34 and bled to the atmosphere via the chimney 26 as normal or alternatively to any one or a combination of the compartments in the fishing vessel 10 and thereafter through the dump pipes 36 and to the atmosphere.

The conduits 34 are normally the same size as standard exhaust pipes or can be bigger to increase flow rate. In this example the exhaust outlet is 6" in diameter and the conduits are 6" or 9" in diameter.

A series of dump pipes 36 are provided which are adapted to receive water and direct it overboard, out of the vessel 10. The dump pipes 36 extend vertically from the centre of the bottom of each compartment of the fishing vessel 10 to a position above the water level 18. In the vessel 10, two dump pipes 36 are normally provided in fish room 16, and one in each of the engine room 14 and forecastle 15°. The top end of all dump pipes 36 have a non- return variable adjusted relief valve (not shown) . A dump pipe 36 is preferably provided in any compartment capable of forming an air-tight seal with adjacent compartments. In alternative embodiments the dump pipes may be lower than the dump pipes shown in the figures so that although they extend above the sea level they only extend to the deck above - this reduces the pressure required to expel water. For example, they may connected to scuppers provided in the side of most vessels, such as the scuppers 37 provided in the side of the vessel 10.

An independent compressor or auxiliary generator (not shown) , may also be provided and connected to the conduits 34 as a secondary standby or to clear exhaust gas from a compartment following extinction of a fire (described below) . The engine 20 and any auxiliary engines (not shown) are fitted with watertight override switches to ensure the engines do not stop when in contact with water since electric switches can short and fail in the presence of water. All engines are also made watertight by the provision of o-ring seals (not shown) on the oil dipstick, oil fillers and other such components.

An auxiliary engine is normally provided in the forecastle 15 of the vessel 10. In certain embodiments the auxiliary engine is also connected to the conduits 34 and air inlet 24 as described for the main engine 20. In the event of failure of the main engine 20 and the auxiliary engine being used to expel water from the vessel, exhaust valves (not shown) provided on the main and auxiliary engine are closed to prevent pressure loss through the engine 20 and out through the air intake 24. These exhaust valves are closed in any engine not in use for the same reason.

Bilge or flood alarms and controls for the various valves are located in an area that is normally permanently manned, such as the bridge 11 or engine control room (not shown) . The valves are operated by any mechanical means with a manual override to be operated from above deck level.

Thus, should the fishing vessel 10 take on water, due to for example the hull or other part of the ship being punctured as a result of the vessel colliding with rocks for example, the vents in the engine room 14 will be closed and the valves within the exhaust gas conduits 34 can direct exhaust gas into the compartment where the water is coming on board which results in an increased air pressure in that compartment. The engine can run with an output pressure of 30PSI which is sufficient to expel water from the vessel and is not too high to cause the engine to stall, as detailed further below. This at first slows the ingress of water because of the higher air pressure than normal. Thereafter, once the air pressure is at a sufficient level, it will force the water out through the damaged area thus allowing the vessel to regain buoyancy and stability.

If the damaged area becomes blocked with debris such as fish boxes, oilskins, tarpaulins etc., the water would then be forced out through the dump pipes 36. Similarly where the water has gained access by an open hatch or door (not shown) where there is no hull damage, the water may be expelled by closing all hatches and doors, directing the exhaust gas into the relevant compartment and expelling the water via the dump pipes 36.

A pressure sensor (not shown) can be provided in each compartment and have its output read from the main controls at the bridge. The exhaust from the engine 20 can then be diverted into the compartment with the lowest pressure in order to balance the ship. This is particularly useful for larger vessels where a number of compartments are present.

Moreover, exhaust gas can be fed into the compartments adjacent to those which have been damaged to increase the pressure therein to a proportion of that in the damaged compartment. This will reduce pressure differential between the damaged compartment and adjacent compartments thereby reducing the stress on the air-tight seal between these compartments. Compartments further away can be similarly pressurised to a proportion of the adjacent compartments to reduce the stress further. For example, the damaged compartment may have exhaust gas directed therein to raise air pressure to 30PSI. The compartment next to it, which is not damaged could then be pressurized up to 25 PSI so that the strain on the seal between the compartments is reduced. The next compartment may be pressurized to 20PSI and so on. In larger vessels such as cruise liners, different decks may also be pressurised to different degrees in this way. This also reduces the localised stress on the hull caused by the increased pressure in one part of the vessel.

For embodiments of the invention to correctly function, the engine or gasifier provided should be capable of creating an air pressure in a compartment which exceeds the water pressure and therefore forces the water out of the vessel. The pressure caused by water is shown in tables 1 and 2 and is detailed in many publications such as the Fitters and Pipe Welder's Handbook, pages 146 - 147 published by Bailey Bros. & Swinfen Ltd. In Fig. 4 it can be seen that the pressure increases as more air is fed into a sealed container. Similarly as water is fed into the container, the air pressure also increases.

Table 1 showing the Heads of Water in Feet with Equivalent Pressures

Table 2 showing the depth of water which corresponds to various pressures.

Tables 1 and 2 show the pressure caused by water - they exclude atmospheric pressure. Thus when calculating water pressure which is exposed to the atmosphere, under the sea for example, the atmospheric pressure of 14.70PSI should be added to the values in table 1 and 2 to determine the total pressure under the water.

The fishing vessel 10 has a draught (that is the distance between the waterline and the bottom of the vessel) of around lβft (5m) . Table 1 shows that the corresponding pressure caused by water at 16ft (5m) is ~7PSI so below the surface the pressure is around 7PSI plus atmospheric pressure of 14.70PSI = 21.7PSI.

A suitable engine for the fishing vessel 10 would be 800 - 1200hp. To test the exhaust outlet pressure at which engines may continue to run, an experiment was carried out as shown in Fig. 2 and detailed below on a 180hp v8 Perkins™ engine.

One of the two exhaust outlets (not shown) on the 180hp v8 Perkins™ engine was fitted with a pipe 52 whilst the other was allowed to blow free. The exhaust outlet and pipe both had a diameter of around 2". A first T-piece 53 was fitted with a relief valve 55 and a second T-piece 54 was fitted with a pressure gauge 56. A shut off valve 58 was attached at the end of the pipe 52. With the engine running at approximately 800 rpm, the valve 58 was closed and a pressure of 60PSI was observed with the relief valve 55 blowing off, and no apparent difference to the performance of the engine over the test period.

Thus such an engine can function and release exhaust gas at least up to 60PSI. In fact, engines used on vessels such as the vessel 10 are far more powerful - of the order to 800-1200hp. Therefore it is clear that if an engine with a power of 180hp can operate with an exhaust pressure of at least 60PSI, then larger engines will also be able to operate at such exhaust pressures.

A number of similar experiments were performed on further engines, the engines having powers ranging from 45 to 115hp.

It was found that these engines stalled when the pressure at the exhaust outlet was up to 40.25PSI. Nevertheless, an operating pressure of, for example, 30PSI is sufficient to expel water at these depths and larger engines are used in practise.

Looking at various engine input pressures after turbocharging, one of Napier' s™ Improved Turbochargers boosts the input pressure to 2.5Kg/cm² (35.558 PSI.) A Deutz UK Ltd turbocharger boosts the pressure so that the engine input pressure is around 1.7bar (+/- 0.5 bar), that is 24.66 PSI for an eight cylinder engine of around 500hp. A Caterpillar™ engine has a boost pressure of around 20 - 25 PSI. The output pressure of an engine is greater than the input and so it is clear that these pressures are sufficient for producing an exhaust with sufficient pressure to expel water at such depths.

In order to reduce the strain on the engine, certain embodiments of the invention use the exhaust from only half of the cylinders. Whilst this reduces the displacement capacity of the engine by half, there is still sufficient capacity to operate as detailed further below. Moreover, whilst the engine's displacement capacity is halved the engine remains running at full revolutions. In preferred embodiments exhaust from all cylinders is utilised when operating at an output pressure of 30PSI. When operating at a pressure greater than 30PSI, the exhaust from half of the cylinders is used.

Further tests were done on a number of other in-line engines which produced an outlet pressure of up to 40.25PSI before stalling providing sufficient exhaust to force out water at a depth of up to (40.25-14.7) = 25.55PSI water which from table 2 is up to 57ft.

Therefore should the vessel's hull be pierced, the engine is capable of generating sufficient pressure to expel water from the vessel since water at a depth of 16ft (5m) is at a pressure of around 21.7PSI. Moreover the pressure at the top of the vessel's draught will be -14.7PSI since it is at the water surface. Therefore the average pressure in the hull with a draught of 5 metres is (21.7+14.7) /2 = 18.2PSI. However, for the purposes of the calculations the pressure of 21.7PSI will be used since holes punctured in a vessel can occur in the bottom of the hull where a pressure of ~21.7PSI is required in order to force the water out.

Thus embodiments of the present invention allow for a vessel in difficulties and taking on water to expel water or delay the ingress of water which can prevent or delay the sinking of the vessel.

Other vessels can have hulls which extend further beneath the water surface but will have commensurately larger engines and so will typically have sufficient volume and exhaust pressures from these larger engines to cope with the increased pressure at greater depths.

The volume of water which can be expelled using an appropriately sized engine for a vessel 10 has been calculated approximately as set out below.

Engine make: 6 cylinder M.A.K. 4-stroke. Exhaust stroke every second revolution so a 600 revs per minute engine has 300 exhaust stroke revs per minute. Volume of engine = No. of pistons x volume of cylinder. Volume of cylinder = stroke length x cross sectional area of piston. Diameter of piston: 0.320m Length of stroke: 0.420m Cross sectional area of piston = Pi x r² 3.142 x 0.160m x 0.160m = 0.0804352m². Volume of cylinder = 0.0804352m² x 0.420m = 0.0337828m³ Volume of engine = 0.0337872m³ x 6 = 0.202697m³ x 300 revs/minute = 60.809metres³/minute x 60 = 3648.5m³/hour

Therefore the engine is capable of producing 3648.5m³ of exhaust gas per hour.

The fish room 16 has a capacity of 1015m³.

Therefore if the vessel has taken on water and the fish tank 16 is flooded, it will take:

1015m³/3648m³h-¹ = 0.278h = -17 minutes to evacuate the fish tank 16 putting aside the changes in volume caused by the change in pressure.

Such change in volume can be approximated using Boyles law, see also Fig. 4 which shows a graph of pressure increase as a function of time as water and air is fed into a container. Boyle's law states that at the same temperature, pressure x volume will remain constant, therefore:

Pressure 1 (Pl) x Volume 1 (Vl) = Pressure 2 (P2) x Volume 2 (V2) . In this case, the original pressure is 14.7PSI (atmospheric pressure) and the final pressure is 21.7psi. Moreover it will be appreciated that the volume will change progressively from 14 PSI to 21.7 PSI as more water and air move into the compartment of the vessel. For the purposes of this approximate calculation, the pressure will be taken to be 21.7psi and the fish room 16 taken to be completely flooded. In practise, the exhaust gas is likely to be fed into a flooding compartment before it is completely flooded and so this calculation is based on almost a "worst case" scenario of one compartment being completely flooded.

Therefore, with a compartment size of 1015m³

V2 = Pl x V1/P2

= 14.7*3648/21.7

= 2471m³ if the full engine capacity is used.

Thus at these elevated pressures, the 3648m³ of exhaust gas produced by the engine in 1 hour will be compressed to 2471m³.

Therefore,

1015m³/2471m³h^"1 = 0.41hours ~ 24minutes to completely evacuate the fish tank 16 assuming pumping does not start until the fish tank is completely full of water, the leak is at the bottom of the hull and the full engine capacity is used.

Further calculations using different sizes of engines and vessels are set out in the table below. The size of the hull is also an approximation - in fact it will be slightly smaller than the length x breadth x height because it is not box-shaped.

Ignoring the change in volume caused by pressure changes. One cause of vessels being lost is when sea-cocks break loose and water is taken on board in an uncontrolled manner. (Sea-cocks are valves provided below the waterline on a vessel which allow for sea water to be taken on the vessel for various uses such as cooling the engine, washing fish, fish holds, fire-fighting or cleaning the deck. )

The following calculation was performed to determine whether the engine capacity is sufficient to expel water taken on board in the event of a sea-cock breaking loose.

The flow rate depends on two main factors - the size of the hole in the vessel and the pressure of the water which of course varies with depth. An exemplary diameter for a main sea-cock is 175mm. Such an opening at a depth of five metres produces a total flow rate of 9 tons of water per minute' This equates to 9 ton per min x 60 = 540 tons per hour. 1 Ton = 1 m³. This is an approximate example only for worst case flow rate for such a sized hole at such a depth. The flow rate will normally reduce as the pressure within the vessel builds up due to water being taken on board the vessel and also due to the air being forced into the vessel to increase the pressure.

As detailed in the first example above, the total capacity of exhaust gas which can be expelled within one hour by the exemplary engine is around 3650m³per hour if the full engine displacement capacity is utilised and taking into account pressure changes, around 2471m³ per hour which can therefore expel water at a much faster rate than it is taken on board. The exhaust from auxiliary engines may also be used to increase this rate.

In this and preferred embodiments of the invention, the gas which expels the water is taken from the exhaust gas of the vessel's engines.

This is compared to bilge pumps which are provided on most vessels. Two 75mm bilge pumps, for example those available from Desmi Ltd, Parkhouse, Staffordshire, UK model SA-80-220/17, are normally provided on a vessel of the size of the vessel 10. These have the capacity to pump water upwards for up to 5 metres and are used on vessels to remove splash water, rain and melted ice. The maximum capacity for such pumps is 40m³ per hour, giving a total capacity of 80m³ before taking into account the reduced volume due to the pressure increase which would make pumps even less effective. For a draught of 5m and an average pressure of 21.7psi over the flooded part of the hull, the volume would be reduced to ~54.39m³ per hour for 2 pumps.

A pump required to meet the rate of water ingress through such an aperture would be required to pump at a rate of 540 m³ per hour. Standard pumps pump a rate of 40m³ per hour (reduced to 27.2m³ per hour per pump because of pressure increase) and so around twenty pumps of the standard size would be required simply to match the water ingress rate. More pumps would be required in order to pump more water out of the vessel than that coming onto the vessel.

A single pump which may have such a capacity could be Goodwin pump with an inlet of 8"/200mm, weighs 1800kg and is around 2.600 x 1.300 x 1.750m in size. This is very unwieldy for a vessel of such a size. Such a pump is detailed in the Longville Pump rental and technical advice book.

Therefore to achieve the adequate performance with pumps, a large heavy pump would be required. This would be less practical and so it is preferred to utilise the exhaust gas from the engine to obviate the need to carry such a large pump.

Moreover the delay in starting a pump would also be crucial. This currently requires a person to go down to the engine room when the vessel is taking on water, spend the required 2-3 minutes to start the pump.

Calculations were also done to determine the volume of water which could be emitted by a compressor. One suitable compressor (not shown) can produce: 170ft³ minute^"1 = 4.δlm^inute^"1 = 288. βm^our^"1. Reduced because of pressure to 195.36m³ hour.

Therefore around three such compressors would be required in order to match the water ingress rate. More compressors would be required in order to pump more water out of the vessel than that coming onto the vessel.

Thus the rate at which an engine exhaust can expel water is much greater than that of conveniently sized compressors and significantly greater than that of conveniently sized pumps.

Therefore although in certain embodiments of the invention, a dedicated compressor or compressors may be used to generate the gas required to increase the air pressure in the various compartments, such embodiments are less preferred because they require an additional powerful compressor or compressors to be carried on the vessel. A compressor may be provided as a standby.

A further application of the present invention is for fire fighting. Where a fire is present in a compartment of the vessel, personnel can be evacuated from that compartment, the compartment sealed and exhaust gas which contains little or no oxygen directed to the compartment with the fire through the conduits 34 and the fire can be extinguished in this way. Alternatively the exhaust gas may be directed through companionways/corridors (not shown) in the vessel 10, heating ducts (not shown) or any other suitable pipe work.

A test was conducted, as shown in Figs. 3a and 3b to demonstrate the capability of exhaust gas to extinguish a fire. Exhaust gas directed through the exhaust gas conduits 34 into said compartment. A steel box 50 section about 0.400m x 0.400m x 4.5m long x 8mm thick, with both ends open had pieces of fishing net 59 and cardboard 61 placed inside and lit. After the fire was well alight, both ends were partly closed. A pipe coming from the exhaust of a running engine was placed into the end of the steel box 50. After a few minutes the fire was extinguished.

After extinguishing the fire, the compressor or ventilation fan (not shown) can be used to clear inert exhaust gas from compartments to allow crew members using proper procedures to enter such areas. In harbour an auxiliary generator may be left running, and an automatic mechanism triggered by bilge, or smoke alarms may be installed to direct the exhaust gas to the required compartment. A manual override is also provided.

Visual (e.g. flashing light) and audio warning alarms may also be fitted on the vessel to draw attention from harbour personnel.

Whilst the example herein is that of a fishing vessel 10, it will be appreciated that the invention can be applied to other types of vessels, although it is particularly suited to small vessels with large engines.

Thus embodiments of the present invention can help to prevent vessels from sinking or allow further time to send emergency signals and direct the vessel back to safety. This can save lives and the cost of replacing lost vessels.

An advantage of certain embodiments of the present invention is that existing vessels can be easily adapted to include the apparatus according to the present invention.

An advantage of certain embodiments of the invention is that the engine can be used for expelling the water and/or fire fighting. This obviates the need, in certain embodiments, to provide separate means to remove the water/extinguish the fire. Such means are typically the most expensive part of the apparatus.

Improvements and modifications may be made without departing from the scope of the invention.

Claims

1. A gas expulsion apparatus suitable for installation into a vessel, the apparatus comprising a device having a gaseous inlet and a gaseous outlet, wherein the outlet is adapted to direct gas into a compartment of a vessel.

2. Apparatus as claimed in claim 1, wherein the apparatus comprises a valve and tubing means which is adapted to direct gas from the gaseous outlet to one or a combination of different compartments of the vessel.

3. Apparatus as claimed in claim 1 or claim 2, wherein the valve and tubing means is operable to selectively direct gas from the gaseous outlet to one of an exhaust and a compartment of the vessel.

4. Apparatus as claimed in any preceding claim, wherein the gaseous inlet is an air inlet.

5. Apparatus as claimed in any preceding claim, wherein the apparatus is adapted for use in a floating vessel.

6. Apparatus as claimed in any preceding claim, wherein the device is an engine, the engine also being operable to power the vessel.

7. A vessel having a gas expulsion apparatus as claimed in any one of claims 1 to 6.

8. A vessel as claimed in claim 7, wherein compartments of the vessel are sealable such that they are watertight and airtight when sealed.

9. A vessel as claimed in claim 7 or claim 8, wherein the gaseous outlet is connected to a network of input conduits which extend around the vessel.

10. A vessel as claimed in claim 9, wherein input conduits from the network of input conduits extend into a plurality of compartments of the vessel.

11. A vessel as claimed in any one of claims 7 to 10, wherein the vessel comprises a plurality of release conduits extending from each of a plurality of compartments of the vessel and the release conduits are directed to the side of the vessel, said release conduits being adapted, in use, to transfer water from the compartments of the vessel out of the vessel.

12. A vessel as claimed in claim 11, wherein the release conduits extend proximate from the bottom of the respective compartment to a height which is above a main deck level of the vessel.

13. A vessel as claimed in any one of claims 7 to 12, having a conduit extending between the gaseous inlet to a position above the normal water line of the vessel, such that, in use, the air for the gaseous inlet is drawn from a level above the normal water line of the vessel, into the device.

14. A vessel as claimed in claim 13, wherein said conduit for the gaseous inlet extends above the level of a main deck of the vessel.

15. A method of mitigating danger in a vessel, the method comprising blowing gas into a compartment of a vessel in order to: (i) delay or reverse water ingress into the vessel; or, (ii) extinguish a fire within the vessel.

16. A method as claimed in claim 15, wherein the gas blown into the compartment is exhaust gas from an engine of said vessel.

17. A method as claimed in claim 15 or 16, wherein gas is blown into compartments adjacent to said compartment of the vessel.

18. A method as claimed in any one of claims 15 to 17, wherein the method is used for a vessel which is at least partially above the water.

19. A method as claimed in any one of claims 15 to 18 for delaying or reversing water ingress into a vessel, the method comprising blowing gas into a compartment of a vessel, and at least one of: (i) expelling water from said compartment of said vessel out of the vessel; or, (ii) reducing the rate of water ingress into the compartment of the vessel.

20. A method as claimed in any one of claims 15 to 18, wherein the method is used to extinguish a fire in a compartment of a vessel, the method comprising blowing gas into said compartment of the vessel.

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