On bareboats and houseboat rentals, the basic electrical system is a direct current, or DC, system (represented by the red and black wires shown in the layout diagram). This is so because the ignition system of a marine engine requires direct current to operate; and on a bareboat at sea the engine's battery, which produces direct current, serves as the ultimate source of electrical power during bareboat charters.

While some of the current originating from the battery goes straight to the starting system, the rest flows into a unit called the DC distribution panel. This panel then parcels out current to such fixtures as the running lights, cabin lights, bilge pump, depth sounder and so on.

Your bareboat may also carry a second, auxiliary system of alternating current, or AC wires (coloured orange), which can be operated when your bareboat is berthed in a marina... by plugging into an electrical outlet ashore. The AC power, the same as that in any home, travels first to the boat's AC panel. This versatile unit is equipped with a voltage meter to warn against high or low voltages that could damage the boat's electrical equipment, and it also contains fuses to break a circuit in the event of a dangerous surge of power...from the panel, AC power goes out to conventional outlet plugs around the bareboat. High-voltage appliances that require AC power, such as cabin fans, refrigeration compressors and television sets, can be plugged into these AC outlets.

The coloured red, black and green wires on the motor cruiser above (similar on a sailing yacht) illustrate its DC system. The red ones are power-delivering, or hot, wires; black are return wires that serve both to complete DC circuits and ground them; green are the earthing wires that link large metal objects together.

Of the three, the earthing wires are least understood by bareboat novices, but they are critical to safety. Without the earthing system, these metal objects could absorb static charges or leakage from the circuitry. Connecting them neutralizes the errant electricity, eliminating or significantly reducing galvanic corrosion and radio interference.

Your 12 volt batteries

During the time of your bareboat charter, batteries will come under their greatest strain in the evening, when lights and other electric's are in use - and when, swinging at an evening mooring on a yacht charter in the Whitsundays, you least want to endure engine noise and fumes to keep them charged.

If the drain on your bareboat batteries increases to the point where demand exceeds supply - lights dim, electronic devices, like a depth sounder, may malfunction, and the engine will just barely crank over - or not at all...If you let this happen, you now have the very real problem of not even being able to start your engine to charge your batteries.

During your bareboat briefing it is important you understand how your boats batteries are wired...so that if they do not automatically isolate the engine starting battery from your domestic batteries...you know how to manually isolate the cranking (starting) battery so the engine starting battery cannot be flattened.

Your batteries will generally need to be charged approximately 2 hours per day...this will be done in conjunction with you running the eutectic refrigeration system during normal cruising time.

It is important during the whole time of your bareboat yacht charter that you are conscious of power usage on your bareboat. Always try to conserve battery power... unnecessary use of saloon and deck lights and instruments i.e., (depth sounder 'on' when at anchor) can drain and damage your bareboats deep cycle batteries.

Conserve battery usage and monitor power consumption by watching your batteries charge meter.

A source of AC underway
Although the high-voltage AC current needed to run appliances like refrigerators normally comes from dockside, a bareboats own batteries can supply a limited amount of AC power at sea with the help of a device known as an inverter.

This mechanism transforms 12-volt DC current into 240 volt AC. AC appliances are plugged into the electrical outlets on the face of the device. Since their power needs are great and could quickly drain a battery.

If you have an inverter on your bareboat operate it only when the boats engine is running - or only for short periods when anchored or moored. Not all bareboats carry inverters, you will need to check the specifications of the boat you intend chartering before your trip, if you intend taking electrical equipment that needs 240 volt power.

Refrigeration

Bareboats are often fitted with a refrigerated compartment operating with a eutectic refrigeration system and optional 240 volt shore power compressor...Also it is becoming more and more common that the refrigeration system runs on your boats 12 volt electric system.

When disconnected from shore power the eutectic refrigeration system on your bareboat will only operate when the engine is running...If you are motoring around during the day keep the eutectic refrigeration switch on, this will save you running the engine separately...to maintain the correct cooling temperature, your engine should be run at the recommended speed for about one hour twice a day.

Ensure that whenever possible, provisions are hard frozen at the time you place them on board prior to your charter. This will ensure adequate cooling and minimal spoilage.

It is recommended all meat and some of your milk and bread be hard frozen. Always plan to eat your perishable foods first. Do not overload the refrigerator with unchilled produce or beverages. For best results:

• Try to keep the lid open as short a time as possible
  
  
• Stack frozen foods against the eutectic copper tank
  
  
• Do not place warm or hot items in the refrigerator