6.2 SEA WATER SYSTEM

The sea water systems on board are:

• Cooling system for air conditioning heat exchanger;
• Cooling system for engines;
• Generator cooling system;
• Fire-fighting system;
• Water maker system;
• Cooling system of propeller shafts seals;
• Seakeeper cooling system.

1. Propeller shaft sea water intake
2. Engines seawater intake
3. Thruster pump seawater intake
4. Generators seawater intake
5. Air conditioning seawater intake
6. Gyroscopic stabilizer seawater intake
7. Multipurpose seawater intake

The engine cooling system consists of two circuits, one for the starboard engine and the other for the port one.
Sea water is sucked directly by the engine inner pumps by means of a sea cock equipped with cut-off valve and strainer.
The sucked water, flows partially through the strainers and is then delivered to the heat exchangers of the engines, and discharged overboard by means of gas exhaust. A further part of water is delivered to the heat exchanger of the gear box and then drained overboard through the exhaust pipe.

The power generators cooling system, consists of two circuits, one for each power generator.
Sea water is sucked directly by the inner pumps of the generators by means of two sea cocks equipped with cut-off valve and strainer (3). The water sucked by the generators, flows through the strainers, and is then delivered to the heat exchangers of the same generators and then discharged overboard, together with the exhaust gases by means of wet mufflers and water/gas separators.

The seawater/fire-fighting washing system consists of an electric pump that sucks sea water through the manifold of the centralised seawater intake and sends it to the connections for the fire-fighting hoses and washing the black and grey water tanks and washing the anchor chain.
In the cooling system for air conditioning sea water is sucked by two electric pumps by means of a sea cock equipped with cut-off valve and strainer.
The sucked water is delivered to the heat exchanger of the air conditioning unit, located in the engine room, and then drained overboard.
The sucked water is sent to the heat exchanger of the air conditioning unit located in the bilge under the aft garage and then discharged outboard.
The filtered seawater intake and the two electric pumps for the air conditioning unit are located in the bilge below the aft garage.
The seawater system for the watermaker consists of an electric pump that sucks sea water through the centralized seawater intake manifold. The brine remaining after the desalting process is discharged overboard.
The seawater system for cooling the gyroscopic stabiliser consists of an electric pump that sucks in seawater through a seawater intake equipped with an interception valve and strainer.

The yacht is also equipped with two sea water intakes equipped with strainers for cooling and lubricating the shaft seal.

WARNING

In case of engine room flooding, it is possible to use the engine cooling system to pump water from the bilge in large quantities as follows:

• Start the engines;
• Close the engine seacocks and by open the bilge suction valves.
  

The valves activation must absolutely be wanted and not accidental. Should it be necessary to use this draining system, the bilge level must be checked continuously, because in case of complete drainage, the engines will not be cooled down.

CAUTION

Be very careful when resetting the valves to sea suction if the bilge is dry, so as not to damage the engine parts.

DANGER

Do not use water to fight fires with electric circuits powered, as this could cause electric shocks or short circuits, feeding the fire even further.

This yacht is equipped with a Trailing Pump on the gearbox module; this system allows navigation with a single engine while safeguarding the mechanical components of the engine switched off.
For long distances a “sea water” cooling circuit has been provided with the following modes of use.

For prolonged navigation with one of the two engines switched off, operate as follows:

• With both engines working, the 3-way valves, positioned between the engine and the inverter, must be kept in configuration “A” (no partialization of the water flow towards the other inverter);
• If one of the two engines shuts down or fails (Engine OFF in the figure), the corresponding valve must be set to position “B” (the inverter now receives part of the cooling water coming from the delivery of the gear in operation).