On a motor cruiser or on a yacht, four discrete plumbing systems are packed into the below decks area.

1. The Fresh water system supplies fresh water for drinking, cooking and washing to a galley sink. A hand pump on the sink or electric water pump draws the water from a tank, usually positioned in the bow to counterbalance the weight of other heavy installations farther aft. This tank is vented, allowing air to enter as the water level changes; otherwise, a vacuum left by departing water would make pumping difficult. The waste water from the sink flows out of the boat by gravity; the outlet is located just above the waterline so that dirty water does not dribble any appreciable distance down the topsides called the Marine Head (toilet) System
2. A second system provides raw water for the toilet. A pump beside the toilet draws water through a seacock at the bottom of the hull and, depending on the age of the boat, flushes it either overboard or, as in a newer craft like this one, it can be flushed into a vented holding tank that is emptied when the boat docks at a marina.
3. In the third system, another seacock admits raw sea water to cool the engine. After the cooling water has passed through the engine block, the system's pump, powered by the engine itself, expels the water via the exhaust pipe along with the engine's exhaust gases.
4. The fourth - and the simplest - Bilge Pump System pumps out any water that has collected in the bilge. A strainer-covered hose end resting in the deepest part of the hull sucks up the water through a pump and discharges it overboard through an outlet near the waterline.

A seacock controls the flow or raw water into toilets or engine-cooling systems by a rotating valve that opens when the handle is vertical and closes when it is horizontal.

All bareboats are fitted with two or three fresh water tanks of varying capacities.

Generally, the water flow from these tanks is controlled through diverter valves allowing you to use the tanks progressively.

To maintain boat trim, use any stern tanks first... using the bow tank last keeps that weight of water forward, until the stern tanks empty.

Pressure system

Bareboats generally operate with a fully pressurised hot and cold water system...for this system to operate you need to turn on the fresh water pump which operates on 12v power. If you hear this pump running and you are not using water (all taps closed)...switch off the pump immediately... before the pump and impeller are damaged, look for the reason. You can review a long list... Refer to Fresh water pump trouble-shooting chart.

1. You are out of water in the tank you are using...turn diverter valve to an unused water tank.
   
2. You have a leak in the supply line from the pump to the taps... after locating leak, repair if possible after isolating that section.
   
3. The pressure switch is faulty... report to your charter operator.

Hot water cylinder

The hot water system almost always works through a heat exchange connected into the main engine. The water automatically heats when the engine has run for approximately 20 minutes. Water will stay hot in the insulated hot water cylinder for a considerable period. Best time to have a shower is during or directly after the motor has run.

When connected to the 240 volt shore power at a Marina, the water is heated (on some bareboats) by turning on the 'Water Heater' switch on the 240 volt switchboard.

Refilling fresh water tanks

In the Whitsundays, Abel Point Marina or Shute Harbour are the only places you can be certain your fresh water tanks can be refilled with water of good quality...so use sparingly.

Your fresh water hose is often attached to a sea water valve and used to hose down the boat or anchor... because this hose is used with sea water, flush fresh water through, before you fill the fresh water tanks.

Filler caps are marked 'water', make certain you only put water into these locations as this can have immediate and expensive consequences if you mistake the 'Diesel' filler cap.

Shower

It is recommended that everyone restrict themselves to a maximum of 2 minutes of water time per person per day.

By wetting yourself down then turning off the water while soaping, you will find you have ample water to rinse.

On most bareboats the shower and hand basin water drains into a sump which operates on a float or pressure switch that automatically pumps out the water.

The Ancestral Latrine
On early sailing ships, the crew used the vessel's sharp prow, which was known as the beak head, as an open-air latrine. The latrine was named for its location - an appellation that still survives, even though the head came in from the cold more than a century ago.

Marine toilets or 'heads' as they are called, come in both manual and electric versions. To keep the gaskets and the valves of the pumps functioning smoothly during your charter, simply pour in about a quarter of a cup of vegetable (cooking) oil into the bowl once daily and flush it through the system.

The chief problem you could encounter (with a marine toilet) is their cantankerous inclination to clog, especially if used as receptacles for such objects as cigarette ends, tampons or soap wrappers etc. Remember, with the exception of toilet paper nothing goes into the toilet that has not passed through your mouth first... a service call to clear a blocked toilet will be charged to you...The most vulnerable spot is usually the internal discharge valve that prevents waste from being drawn back into the pump. This valve is known as the joker - possibly a corruption of the word choker, because anything that is lodged there effectively chokes the pump. However the problem can be fixed with relative ease...just open the joker and remove the obstruction...see the diagram below.

To remove foreign objects carelessly or inadvertently dropped into the bowl, unscrew the discharge tailpiece from the discharge line and lift out the rubber joker valve. If the valve is in sound condition, wipe it clean and reassemble the unit; otherwise, replace it.

In a typical hand-operated marine toilet, the up-and-down action of a pump circulates raw water and flushes waste into a holding tank - or overboard - when the flush-valve lever is opened.

If a manual pump handle is hard to operate - or an electric pump seems balky - be sure the seacock is wide open and there are no kinks in the intake and discharge lines. Movement of a boat underway can shut the seacock or crimp the intake line, thereby cutting off flow.

How the head works

The up-and-down action of a pump circulates raw water and flushes the waste overboard or into a holding tank - if a manual pump handle is hard to operate - or an electric pump seems balky - be sure the seacock is wide open and there are no kinks in the intake and discharge line.

To use the toilet:

1. Push the black lever to the 'wet bowl' position and then pump until water enters the bowl.
   
2. Use the toilet... after use, with the lever still pushed to the 'wet bowl' position...pump for 15-20 strokes to evacuate the bowl and flush out the discharge lines.
   
3. Now push the lever to the 'dry bowl' position...and pump the bowl dry.
   

The seacocks for both the 'sea water' inlet and 'waste outlet' pipes in the sewerage bilge are set in the open position at the commencement of your charter...they should not need adjusting in normal circumstances.

A cutaway view of a manual toilet pump traces movement of water during the intake phase of operation and pinpoints maintenance spots.

On the downstroke, as shown here, the piston draws clean water through the intake valve, while forcing waste water from the cylinder into the discharge line through the joker valve.

On the upstroke the clean water will be forced past the outlet valve and into the bowl. The upstroke also draws a new charge of water and waste from the bowl into the cylinder.

Bilges are those parts of your boats hull below water level, containing the engines, plumbing and drainage pipe work... bilges should be dry.

But boats being boats water will occasionally leak into the bilges... through leaking drive shaft seals, valves leaking in hull fittings, leaking water tanks, deck hatches etc. so it is important that you check your bilges daily.

You need to be certain there is no unusual increase in bilge water levels. The engine room bilge is particularly important and it should be checked before you start engines.

Submersible Bilge Pumps

Each bilge pump operates automatically, with each pump being monitored by pressure or float switches which turn pumps on and off as needed.

Bilge pumps can be located in a number of locations - particularly if your boat is compartmentalised.

Once water reaches a certain level in your bilge, the bilge pumps automatically engage and an audible alarm sounds. Pumps generally come on when there is approximately 75mm of water in the bilge and off when the water has been pumped down to 25mm. If a pump and alarm comes on occasionally this is not cause for concern. However, if they stay on, or come on frequently... check the bilge directly by visual inspection, and see if you can locate the cause.

It is also important to check over the side to see if water is being pumped out when the pump is on.

On most boats you can however, temporarily override the automatic pump by switching to manual operation...this will pump the bilge drier. Return the switch to automatic after the manual operation is completed. Under no circumstances would you switch off the automatic pumps... report any problems or concerns immediately to your charter operator.

Troubleshooting your electric bilge pump

An electric bilge pump is designed to keep operating even if completely submerged. Whenever such a pump slows down or stops altogether, the trouble maybe that something has clogged the impeller - the rotating element fixed at the base of the pump housing - see Figure A

Dismantling the pump for cleaning is a simple task, since the impeller's only connection to the motor is through the drive shaft - which is designed to be disconnected easily. A firm tap on the discharge hose will help disengage this connection, allowing the impeller and motor housings to be slipped apart - see Figure B

Once the pump has been removed, dislodge any debris or sludge from the impeller blades with your finger.

Manual bilge pumps

In the event of an emergency, and you lose 12v power to the bilge pumps and water is entering the bilges, you will need to use the standby manual pump installed on all bareboats. During your boat brief make certain you fully understand its operation and just what you need to do if it fails to pump properly.

If the pump fails to prime or chokes during operation:

1. Check the inlet hose connection is airtight and does not collapse during the section stroke.
   
2. Inspect inlet and outlet valves for blockages. Clear with finger or screwdriver.
   
3. Inspect diaphragms for damage and check that they are seated properly in the cover groove.
   
4. Solid objects in the body of the pump may not prevent its operation but should be removed to prevent damage.

Since a manual diaphragm bilge pump is very difficult to operate when submerged, it should be installed well above the lowest point of the bilge, depending on hull conformation.

And because the pump is subjected to considerable wrenching by the operation of its hand lever, it should be securely mounted.

Additionally, the intake hose should extend to the deepest part of the bilge, and the hose's end be fitted with a metal strainer to prevent the pump clogging.