What Is a Port navigation light?
A port lamp (or red navigation light) is a required fixture installed on the left-hand side (port side) of a vessel’s bow. It projects a steady red light across a horizontal arc of 112.5 degrees, visible from directly ahead to 22.5 degrees abaft the beam.
This navigation light helps other vessels identify your boat’s direction of travel and avoid potential collisions. When another boat sees your red light, it indicates your vessel is moving from their starboard side to their port side, meaning they should give way under navigation rules.
Function and Placement
The port lamp works in tandem with the starboard (green) navigation light to define a vessel’s orientation. Together, they form a complete visibility system that signals position and movement during night navigation or low-light conditions.
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Color: Red
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Location: Mounted on the port (left) bow
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Visibility Arc: 112.5° from the bow to 22.5° abaft the beam
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Minimum Visibility Range:
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1 nautical mile for vessels under 39 ft (12 m)
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2–3 nautical miles for larger vessels
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For compliance and durability, always use U.S. Coast Guard–approved LED navigation lights like DRSA’s Vertical Port/Starboard Lamp Kit. These fixtures are built to handle harsh marine environments while maintaining legal brightness and beam accuracy.
Why Port Lamps Matter
Port lamps are essential for marine navigation safety. They:
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Indicate vessel direction to nearby traffic
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Ensure compliance with COLREGS and U.S. Coast Guard standards
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Enhance night visibility during cruising, docking, or mooring
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Help prevent collisions by signaling movement patterns clearly
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Support multi-light systems including masthead, stern, and anchor lights
Using marine-rated LED navigation lights from DRSA provides consistent brightness, long lifespan, and reduced power draw critical benefits for boats operating on 12V or 24V systems.
Port Lamp Example in Use
Picture a yacht crossing your path at night. If you see a steady red light, that’s its port lamp, meaning it’s moving left across your field of view. You now know to adjust course accordingly under standard navigation rules.
Example in a Sentence
“The port lamp glowed red across the bow, signaling our position to approaching vessels in the channel.”
Synonyms: red navigation light, port navigation lamp
Related Terms: navigation lights, sidelights, combination light, starboard light
Explore Marine Navigation Lighting
Browse Navigation Lights at DRSA.com to find port and starboard LED fixtures, combination lamps, and U.S. Coast Guard–approved marine lighting systems for reliable visibility on the water.
FAQs About Port Lamps
What side of a boat is the port lamp on?
The port lamp is always located on the left-hand side (port side) of a vessel when facing forward. It displays a steady red light, indicating your vessel’s left side to others on the water.
What color is the port navigation light?
The port navigation light is red. When another vessel sees your red light, it knows your vessel is crossing from its starboard (right) to port (left) side and should yield according to navigation right-of-way rules.
How far should a port lamp be visible?
Visibility depends on the size of your boat:
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Under 39 feet (12 meters): must be visible for at least 1 nautical mile
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39 feet and larger: must be visible for 2–3 nautical miles
DRSA’s LED Navigation Lights are designed to meet or exceed these U.S. Coast Guard visibility requirements.
Can I replace an old incandescent port lamp with an LED version?
Yes. LED port lamps are brighter, more energy-efficient, and longer-lasting than incandescent bulbs. DRSA offers LED port and starboard lamp kits that retrofit directly into existing housings and wiring with minimal modification.
What’s the difference between a port lamp and a starboard lamp?
A port lamp is red and mounted on the left side, while a starboard lamp is green and mounted on the right side. Together, they help nearby vessels determine your direction of travel and orientation at night.
Does law require port lamps?
Yes. Under COLREGS (International Regulations for Preventing Collisions at Sea) and U.S. Coast Guard regulations, all powered and sailing vessels operating at night or in limited visibility must display approved navigation lights, including red port and green starboard lamps.
Do LED port lamps draw less power?
Absolutely. LED navigation lights use a fraction of the power compared to traditional bulbs, making them ideal for 12V and 24V systems on sailboats, yachts, and powerboats. They also produce less heat and offer lifespans of up to 50,000 hours.
Can I install port and starboard lamps myself?
Yes, many modern surface-mount LED navigation lights are designed for easy DIY installation. However, for commercial vessels or compliance-sensitive upgrades, professional installation is recommended to ensure alignment and visibility angles meet Coast Guard standards.