The present invention relates to a system for preventing boarding on a ship at sea by intruders, e.g., by pirates or terrorists .

Merchant ships at sea are a vulnerable target for attacks by pirates or terrorists. A number of systems have been proposed to prevent boarding by pirates, such as electrical fences and the use of water cannons.

Japanese patent application JP 7274157 discloses an automatic detection system for detecting approaching pirate ships and automatically start hosing to repel the pirate ship. In practice, such systems are easy to escape and do not form an effective barrier for intruders,

It is an object of the invention to provide an effective security system preventing intruders to approach or board a ship.

The objecε of the invention is achieved with a method of preventing boarding a ship by ejecting heated water as a water curtain between an attacking ship and the ship to be protected, The hot water curtain forms an effective shield, which is much harder to circumvent than the jet of a water cannon and does not need to be directed towards the attacking ship, so control of the water curtain can be achieved in a much easier way. The water can ior example be heated to a temperature of at least 5C°C , e.g., at least 60 ⁰ C, preferably at least 75°, Such hot water curtains form an effective bar for pirates for entering the ship.

Optionally, the ejected water may comprise non-lethal disabling chemical agents, such as a lachrymatory agent, for instance pepper spray, CS gas (2-chlorobenzalmalononj.tr-.le), CR qas (dibenzoxazepxne ) , CN gas (pnenacyl chloride), bromoacetone, phenacyl bromide, or xylyl bromide vinegar acid, or mixtures thereof .

According ro the present invention, a maritime security system can be used, comprising a water curtain generator, a water heater and a pump for pumping water from the heater to the water curtain generator.

Optionally, the system comprises a reservoir for a non-lethal chemical disabling agent, such as pepper spray, and a netering unit for dosing the agent into water to be supplied to the water curtain generator.

The water heater car. comprise a heat exchanger connectable to a cooling system of heat generating equipment, such as for example the main engine, and to a supply of water, e.g., sea water. The heat exchanger comprises heat exchange elements for transferring heat from heated coolant medium of the cooling system to the water. This way, heat generated by the main engine or other heat generating equipment can effectively be uεed to heat the water to be ejected, e.g., to temperatures of approximately 60 - 75°C. The water curtain generator can. for instance comprise a tubular line comprising a plurality of aligned nozzles and means for fastening the tubular line along at least a part of the periphery of a ship, e.g.; along the railing of the ship to be protected. The line can for example be a pipe line of a non- oxidizing material, such as stainless steel, having pre- attached nozzles to it at a pre-defined spacing. The spacing can be such that the spray pattern of each nozzle overlaps the spray pattern of an adjacent nozzle. Such a pipe can be removable or permanently fixed, as required by the user.

The water to be used for creating the water curtain can be sea water, e.g., water pumped from sea via a fire fighting system.

Optionally, the system according to the invention can be combined with an automatic detection and/or identification system to detect a possible attack by a terrorists ship or pirates ship.

The present invention will be elucidated with reference to the figures wherein:

Figure 1: shows a ship provided with a maritime security system according to the present invention; Figure 2: shows the ship of Figure 1 in cross section; Figure 3: shows a block diagram of a maritime security- system according to the invention.

Figure 1 shows a merchant ship 1 at sea provided with a security system according to the present invention. The ship 1 is shown in schematic cross section in Figure 2. The ship 1 is provided with a tubular line or pipe 2 with a series of aligned nozzles 3 with overlapping spray patterns 4 forming a water curtain 5 which can be used to repel a pirate ship 6 and withhold intruders from ooarding the ship 1.

Figure 3 shows a block diagram of a maritime security system 10 according to the invention. The ship to be protected comprises a main engine 11 and a fire fighting system 12. The main engine comprises a closed cooling circuit 13 ;o dissipate heat generated by the irain engine 11. In the closed cooling circj.it, a cooJant is pumped around to transfer heal from the main engine 11 to a heat exchanger 14. Sea water is pjmped via the fire fighting system 12 through the heat exchanger 14, Heat from the coolant of the main engine cooling system is transferred via the heat exchanger to the sea water. This way, the water can be heated to temperatures of about 70 ⁰ C or higher. The water is subsequently pumped by a pump 15 to a water curtain generator 16. Optionally; a pepper spray reservoir 17 with a metering unit is connected to the water transport line for dosing the pepper spray into the water,

When a pirate ship approaches the ship to be protected, sea water is pumped via the heat ezchanger to the activated water curtain generator 16 to forir a hot water curtain as a shield against the pirate attack,