There are four types of interior light: Dome lights, fluorescent lights, chart lights and bulk lights - each has a particular application on board.
Dome Lights - about 4 - 6" (100 - 150mm) in diameter with a round plastic or glass diffuser, most dome lights have a single bulb, draw around 1 amp and are good for a strong localised light source. Some also have a red bulb to give off a light that won't hamper your night vision.
Fluroescent Lights - should be used for general are lighting as they are more efficient than bulb type lights giving off around three times as much light for the same power consumption. Fluro tubes should be replaced about once a year as efficiency will decrease over time.
Chart Lights - deliver a focused light for working in the navigation area. They are usually mounted on a flexible arm so light can be concentrated on a particular section of the chart.
Bunk Lights - give off enough light to read by without lighting up the whole boat. Placed at the head of each berth they can be recessed or bulkhead mounted.
- Always be sure to mount white lights where they won't shine directly into the cockpit and blind the helmsman.
- Keep a good supply of spare bulbs and tubes on board and a torch in case of power failures.