Marine Navigation Lights: Bulb Replacement Guide
, by Tejas Jani, 3 min reading time
A practical guide to marine navigation light bulbs — common types, base fittings, and how to pick the correct replacement for your vessel.
Marine Navigation Lights: A Practical Bulb Replacement Guide
Navigation lights are a legal requirement for vessels operating from dusk to dawn or in poor visibility, so a failed bulb isn't just an inconvenience — it can mean a vessel isn't compliant to operate. Here's what to know when replacing a navigation light bulb.
Why navigation lights need the right bulb, not just "a working one"
Navigation lights are designed to be visible at a specific distance and colour (red for port, green for starboard, white for stern/masthead, depending on position). This depends on the bulb producing the correct light output — measured in candela (cd) — that the fixture was designed around. A bulb of the wrong wattage or candela rating may technically light up, but could fail to meet the visibility distance your fixture and vessel type requires.
Common navigation lamp specifications
Marine navigation bulbs are typically rated by:
- Voltage — commonly 12V, 24V, or 220V depending on the vessel's electrical system
- Wattage — ranges from around 10W (smaller signal/indicator lights) up to 85W+ (higher-output navigation lights on larger vessels)
- Candela (cd) rating — this determines visibility distance; common ratings include 18cd, 26cd, and 50cd
- Base type — common bases include BAY15D, BA15D, BA22D, E27, and P28s
Common base types explained
- BAY15D / BA15D — bayonet-style twist-lock bases, widely used across smaller navigation and signal lights
- E27 — standard screw-thread base, used in some navigation and Aldis-type signalling lamps
- P28s — a specific base type used in some buoy and navigation lamp fittings
Buoy lamps vs vessel navigation lamps
It's worth distinguishing between buoy lamps (low-power, designed for long, unattended operation in fixed navigation aids) and vessel navigation lamps (fitted to boats and ships, generally higher output and replaced as part of routine vessel maintenance). These aren't interchangeable — a buoy lamp's design prioritises longevity over brightness, while a vessel lamp prioritises visibility distance.
How to find the right replacement
- Check the old bulb for printed voltage, wattage, and candela rating
- Note the base type — this determines physical fit regardless of other specs matching
- If replacing a buoy lamp specifically, confirm you're ordering a buoy-rated lamp rather than a standard vessel navigation bulb
Browse navigation lamps
We stock a range of genuine marine navigation and buoy lamps from established brands including Radium, Schiefer Lighting, Danlamps, and Dr. Fischer.
Not sure which bulb your vessel or fixture needs? Send us the base type or a photo of your old bulb and we'll help confirm the right match.