Signals for a Power-driven Ship Under Way (At Night)

Two Masthead Lights

(If the vessel is less than 50 metres in length, then only one light would suffice). These lights are carried one behind the other on the two masts. The forward light is lower than the after light. Their visibility is at least 6 miles and they show a white light over an arc of 20 points of the compass (225°), namely from right ahead of two points abaft the beam on either side.

Two Side Lights

A green light on the starboard side and a red light on the port side; these are generally carried abreast the bridge and are provided with special screens so that each light is visible only on its own side from right ahead to two points abaft the beam. Screens are painted matt black. Visibility of these lights is at least 3 miles.

One Stern Light

It is fixed right astern and shows a white light over an arc of twelve points of the compass (135°) namely from right.

Ship at Anchorage

A ship of 50 metres or more in length will have one white light in the fore part of the vessel and a second white light at a lower level near the stern. Both lights are to be visible all around the horizon for a distance of at least 3 miles. If the ship is less than 50 metres long, only one all round white light is required. It may be of reduced visibility as well, but of not less than 2 miles.

Ship Not Under Command

If not making way through water, the ship shall show only two red lights one over the other at least 1.5 to 2 metres apart, visible all around the horizon for a distance of at least 3 miles.

These lights are either hoisted on a flag halyard on the bridge or shown on the Christmas tree if the ship has one. If the ship is making way through the water, she shall also show the two sidelights and the stern light.

Ship Aground

Every ship when aground shall show the appropriate anchor lights and the two red lights for vessels not under command.

Emergency Lighting

Depending on the ship's classification, e.g. ferry, RORO, gas carrier, etc., and tonnage, the SOLAS Convention prescribes minimum requirements for emergency lighting throughout the vessel (Refer to the SOLAS Regulations in Chapter 4).

Emergency light fittings are marked, often with red paint, etc, to indicate their function. The emergency lighting is continually powered from the ship's emergency switchboard at 220V a.c; Chapter 4 elaborates this aspect. A few emergency lights may be supplied from the ship's 24V d.c. battery, e.g., at the communication post in the wheelhouse, and in the machinery space, including the -steering flat (Refer Figures 3.9 and 22.13). Modern emergency lights are generally installed within the normal lighting fixtures and some shipping companies now fit special battery-supported light-fittings along main escape routes in the engine room and accommodation, and at the lifeboat station on the deck. These lights can also be found to be an integral part of the general light-fitting e.g. a fluorescent tube can be designed to house an emergency light that is supplied from an independent emergency source of supply as mentioned in the regulations. Generally, such emergency lights in the accommodation are arranged to produce light immediately upon mains failure; emergency lights at the boat station are switched on when required. Inside the fitting, a maintenance-free battery, usually the nickel-cadmium type is continuously trickle charged from the normal mains supply via a transformer/rectifier circuit. The battery is then available to supply the lamp via a d.c. to a.c. inverter when the main power is absent. Usually the battery will only function for a few hours. Such battery-supported light fittings can be simply tested by switching off the normal mains power supply or, in some cases, by a test switch on the actual fitting. Periodic inspection and testing of all emergency lights is an essential requirement on all ships. This is done once a week or as would be deemed necessary. To conclude, it is important to note that installations on board vary not only between different classes of vessels, but also may be customised.

The relevant circuits and layout diagrams must be referred to in order to obtain adequate information of your ship's lighting system, as it is vital to everyone around you!