PEL SECTOR LIGHTS
Definition
The PEL Sector Light is a land-based navigation light which shows a different colour when viewed from different angles.
What the Mariner Sees
The mariner sees a single light - which is red, white or green in colour at any point in time. From the colour of the light he can determine the lateral position of the vessel. Sometimes the colours can alternate between any two of these colours - see
oscillating boundary.
Videos
To view a video describing PEL light operation, click on the links below:
How Accurate is the PEL Sector Light?
The accuracy of a sector light has two components: the sharpness of the colour change and the actual position of the sector boundary (compared to the intended position).
PEL Sector Lights are very accurate on both components. A complete colour change occurs across a sector boundary within 1 minute of arc (0.02°) in most models. This would be a lateral distance of just 1 metre at a viewing distance of 3.4 km.
The placement of sector boundaries is accurate to within 1-3 minutes of arc.
Where are PEL Sector Lights Used?
PEL Lights are most commonly used to mark the required sailing line of a vessel, such as the entry to a port or harbour. But they are used in many other ways, including marking the location of underwater cables or pipelines, safe anchorages, dangerous or rocky areas, turning basins, fishing zones and exclusion zones.
Advantages of a PEL Sector Light
Unsuitable Site Geography
No places to locate two towers with sufficient lateral separation.
Examples: the leading line comes to the base of a cliff, or passes under a bridge, or across an island or narrow peninsula.
Restrictions on Site Availability
There are locations, but the landowner does not want to allow access for a tower. This is becoming common in large ports, where a tower would disrupt the land use.
High Cost of Two Structures
Where new or replacement structures are required, the project cost can often be halved by erecting a single tower and installing a PEL Sector Light.
Increased Resolution
In some cases a PEL Sector Light can provide greater resolution than a 2-station range because of the digital' nature of the PEL signal. See comments under Technical Terms, and Major Projects (under About Us).
More Information
Check on the pages for PEL-3 and PEL-6 Sector Lights.
For detailed technical information and specifications, download the PEL Sector Light brochure (2 parts, both pdf files):
Part 1 contains general information and PEL-3 data.
Part 2 contains installation information and PEL-6 data.
Maintenance Video
To view a video detailing changing lamps in a PEL light, click on the link below: