Navigation Lamp Wiring

by James W. Hebert

Control of a vessel's navigation lights is often accomplished by a single switch with multiple positions. On small boats there generally are only three positions: OFF, ANCHOR, and UNDERWAY. Electrical schematic diagrams are presented to show the usual wiring for control of the lamps which will produce the proper display of navigation lighting.

Sidelights and All-round White

Control of the NAVIGATION LIGHTS on most boats using sidelights and an all-round white lighting scheme is typically accomplished with a single switch, usually a marine-grade three-position push-pull switch. The positions are OFF (pushed in all the way), ANCHOR (pulled out to first stop), or UNDERWAY (pulled out all the way). The ALL-ROUND WHITE light is shown in both ON positions; the SIDELIGHTS are shown only in the second ON position. On smaller boats the SIDELIGHTS are often combined into a single lamp and carried on the bow instead of two separate lamps as shown.

Drawing: Schematic Diagram of Navigation Lamp Wiring on Boston Whaler boats

Sidelights, Masthead Light, Sternlight, Anchor Light

Some BOSTON WHALER boat with a center console employ a more complex scheme for their NAVIGATION LIGHTS using a dual-bulb masthead lamp where each lamp illuminated a different sector, separate sidelights, and a sternlight. These are also often controlled with a single switch, again a marine-grade three-position pull-push switch. The positions are OFF (pushed in all the way), ANCHOR (pulled out to first stop), or UNDERWAY (pulled out all the way). The dual-bulb lamp fixture which is normally located at the center console serves a dual purpose as both a MASHEAD LIGHT when underway (only forward-facing sector is illuminated) and as an ANCHOR LIGHT when at anchor (both forward-facing and stern-facing sectors illuminated). The SIDELIGHTS and STERNLIGHT are only illuminated when underway.

Drawing: Schematic Diagram of Navigation Lamp Wiring on Boston Whaler boats

Note that the Boston Whaler installation of navigation lamps makes use of a specialized lamp that serves a dual purpose: it can be a masthead light when only the forward sector is illuminated; and, it can be an anchor light when both forward and aft sectors are illuminated. This special lamp could be replaced by two separate lamps, one a masthead light and the other an anchor light. If that is done, the simplest control wiring would be to use two switches, one to control the running light and a second to control the anchor light, or a single switch with two ON positions like the COLE-HERSEE M-531.

Cole-Hersee M-532 Switch

A specialized COLE-HERSEE switch (Model M-532) is often used to control the display of navigation lights on small recreational boats when the dual-purpose lamp is used for both masthead and anchor lighting.

Photo: COLE-HERSEE M-532 Switch

Details of the COLE-HERSEE M-532 switch are shown in their special switch catalogue. On the catalogue page the switch is described as a three circuit switch. From the nomenclature used on the catalogue page I infer the following:

I can summarize the switch as follows:

There is no guarantee that the color of the insulation on the wiring associated with the navigation lamps on a particular boat will match the colors I show in my diagram above. Rather than just relying on the wire insulation color to establish what lamp circuits are fed by a particular wire, perform this procedure to identify the function of each wire in the navigation lamp circuits:

Cole-Hersee M-531 Switch

There is a somewhat simpler switch made by Cole-Hersee, their M-531, that sometimes is used for some boat electrical circuits. This switch is a three-position switch, as follows: OFF, ON-1, ON-2. The switch has three terminals, marked B (for battery), A (for first circuit), and H (for second circuit). The M-531 switch works as follows, as best as I can tell from the information furnished by Cole-Hersee about it:

If that is how the switch works, there is no way to use this switch to control sidelights and a white all-round light so that only the white all-round light shows in ON-1 position and then both the white all-round and sidelights show in ON-2 position. It just cannot be wired to perform that function. An M-532 is needed.

In complete contradiction to the above, it has been reported by others that you can use an M-531 to control sidelights and a white all-round light as would be desired. I seriously doubt this to be true. In order for that to be true, the switch action would have to be different than Cole-Hersee describes. There is no reasonable basis to assume the switch works differently that the manufacturer describes, so I assume these reports from other are wrong and should be ignored.

DISCLAIMER: This information is believed to be accurate but there is no guarantee. We do our best!

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Copyright © 2006 by James W. Hebert. Unauthorized reproduction prohibited!

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Author: James W. Hebert
This article first appeared June 07, 2006.