Boat Lights: How to Choose Marine Lighting
Boat lights are not one product. A red sidelight, a deck step light, a cabin downlight, and a fixture under the hull each do a different job. Pick the job first. Then match the fixture to the boat you already own. A light that looks right in a catalog can still be the wrong size, voltage, or color for that job.
Call (954) 375-0100 to talk through your boat-light project
By Maria Villanueva, Sales
Apollo Lighting began in 1994 and serves boaters from its Fort Lauderdale store. Lighting is the specialty. This guide covers the choice, not the install. It will not tell you that one retrofit kit fits every boat. If the exact replacement is gone, a similar fixture is the honest next step, and only after the old one is measured.
Start with the job each boat light has to do
Most projects fail when every fixture is treated as "more light." Required lights tell other boats where you are. The rest help you see the deck, the cabin, or the water. Those jobs should not share one switch or one color.
Sort the project into five groups before you open a product page:
- Navigation lights show your heading and your size at night and in fog.
- Courtesy and deck lights light steps, gunwales, and work areas without blinding the helm.
- Underwater lights light the water beside the hull. They are not a substitute for running lights.
- Downlights light cabins, heads, and overhead spots where people read or cook.
- Linear LEDs run in a strip under a gunwale, along a toe kick, or inside a locker.
Write the job next to each dead or dim fixture. "Port sidelight," "cockpit step," and "galley overhead" are useful notes. "Needs LEDs" is not. The marine lighting collection is organized the same way, so the note tells you which shelf to open.
Also note how the boat is used. A charter boat that runs after sunset needs reliable navigation lights and calm deck light for guests. A marina workboat may care more about a spreader or deck flood. A weekender may only need to replace one cracked lens. The use decides the budget better than a wattage number does.
Boat lights that other boats must be able to read
The Inland Navigation Rules govern required navigation lights; decorative and underwater lights must not be mistaken for or obscure them. Under the Inland Navigation Rules, the lights in Rules 20 through 31 must be shown from sunset to sunrise. In that window, other lights are allowed only if they cannot be mistaken for the required lights. They also must not hide those lights or block a proper lookout. If you carry the prescribed lights, show them in restricted visibility by day as well. The text is in 33 CFR 83.20.
For a power-driven boat underway, Rule 23 calls for a forward masthead light, sidelights, and a sternlight. A second, higher masthead light is required at 50 meters and optional below that. A powerboat under 12 meters may instead show an all-round white light plus sidelights.
Minimum ranges change with length. Under 12 meters, Rule 22 sets a masthead light at 2 miles, a sidelight at 1 mile, and a sternlight at 2 miles. Those ranges are in 33 CFR 83.22 and 33 CFR 83.23.
Color and arc matter as much as brightness. Port is red. Starboard is green. The stern light is white and faces aft. A masthead light is white and faces forward over a set arc. A pretty white deck flood pointed ahead can look like a masthead light to someone crossing your bow. Keep decorative lights off whenever they could be mistaken for required lights, reduce their visibility, or interfere with a proper lookout while you are underway at night.
When you replace a navigation light, match the approval and the mounting, not just the lens color. The Coast Guard accepts ABYC C-5 as equivalent to the older UL 1104 for navigation-light certification. C-5 covers LED and incandescent lights, including visibility, color, and labeling. Read ABYC's June 2025 announcement.
On the boat, confirm the fixture is meant for that position. Confirm the lens is still the right color. Confirm the base fits the hole or pole you already have.
Do not assume a new LED drops into an old socket and keeps the approval. Some boats need the whole housing. Bring the old part, or a clear photo of the base and the lens markings, when you shop the navigation lights. Wiring diagrams are a separate job. This guide stops at choosing the fixture.
Courtesy, deck, and spreader lights for moving around
Courtesy lights are the small, low fixtures at steps, gunwales, and walkways. Their job is to show an edge, not to light a workbench. Warm white or a soft amber is easier on night vision than a harsh cool white. Keep them out of the helm's direct view. A light that shines into the driver's eyes is worse than no light at all.
Deck and spreader lights sit higher and throw a wider pool onto the cockpit or the side deck. Use them while docking, landing a fish, or working a line. Turn them off once you are underway if they wash out the navigation lights. A spreader aimed down at the deck is a different product from a docking light aimed forward. Do not swap those jobs because the housings look similar.
On a replacement, measure three things before you buy:
- The cutout or the screw pattern on the old light.
- The voltage at that circuit, most often 12 volts on a small boat and sometimes 24 volts on a larger one.
- How much of the fixture sits above the surface, so a foot or a line will not kick it.
A surface-mount courtesy light will not fill a recessed hole, and the reverse is also true. If the old housing is cracked but the cutout is sound, you may only need a new lamp of the same shape. If the cutout is swollen or the gasket is gone, replace the housing so water stays out.
Browse courtesy lights and deck and spreader lights with those measurements in hand. Staff can compare a similar option when the original part is discontinued. They cannot promise a fit from a model name alone.
Underwater lights, and what they are not
Underwater lights make the water beside the hull visible. They help at a dock, on a mooring, or while swimming. They do not meet the navigation-light rules, and they should not be on when they could be confused with a required light. Treat them as a separate circuit with its own switch.
The hard part is the hull, not the color chart. Thru-hull lights need a location that misses tanks, stringers, and other fittings. Some surface-mount models may avoid a through-hull light opening, but cable routing and entry still require confirmation by a qualified installer. Depth, hull material, and paint all change what will physically fit. That is why there is no standard underwater retrofit kit.
Leave color and fishing technique for a dedicated underwater-light decision. For this project, decide only whether you want light in the water at all, and whether the hull can take a new fitting. Then look at underwater lights with the hull facts, not with a wattage guess. If you are unsure about a hole below the waterline, ask a marine contractor before you order.
Downlights and linear LEDs inside the boat
Downlights are the overhead fixtures in a cabin, head, or hardtop. They should be bright enough to cook or read, and dim enough for a quiet night aboard. Many boats want two levels: a brighter white for work, and a lower warm setting after dark. A downlight that cannot be dimmed will feel harsh at anchor.
Match the ceiling cutout and the depth above it. A fixture that is too deep hits the headliner backing or a wire run. A fixture that is too shallow will not sit flush. Note whether the old light used a spring clip, screws, or a surface ring. The downlights collection is the right place once you have that cutout size.
Linear LEDs are strips and bars, not round lamps. They tuck under a gunwale, along a cabin toe kick, or inside a locker. Cut length only if the product is sold as cuttable, and only at the marked points. A strip made for a dry cabin may not be rated for open-deck spray; verify its wet-location rating. Ask for a marine strip with a sealed jacket if the run sees spray.
Consider separate circuits for interior and exterior runs, subject to the boat’s electrical design. A cabin strip left tied to a deck switch will either waste power or leave you in the dark in one of those spaces. See linear lighting and interior lighting as separate shelves for that reason.
How to match a replacement to the boat you have
Replacement work is most of what we see. The old light is cracked, yellowed, or out of production. The boat is not getting a blank-sheet redesign. Fit depends on the equipment already there. Use this check before you add anything to a cart.
| What to confirm | Why it matters | If it does not match |
|---|---|---|
| Job of the light | Navigation, courtesy, underwater, downlight, and linear are not interchangeable. | Stop and pick the collection for that job. |
| Voltage | A 24-volt fixture on a 12-volt circuit may not operate as intended; verify the product’s input range. | Match the circuit, or ask before adding a driver. |
| Cutout, base, or length | The new lamp has to use the hole, pole, or run you already have. | Look for a similar housing, not a forced fit. |
| Color and aim | Required lights have fixed colors and arcs. Deck lights should not aim into the helm. | Choose a different optic or mounting height. |
| Wet location | Spray, a cabin, and underwater are three different seals. | Do not use a dry interior lamp outside. |
Photograph the old lens markings, the back of the housing, and a tape measure in the cutout. Those three photos answer more than a brand guess. Apollo's own marine lights sit beside other marine brands in the Apollo Lighting collection. If the exact part is gone, ask for a similar option. Do not accept a guess about compatibility.
Power is the other limit. LEDs draw less than old bulbs, which helps a small house bank. A boat full of new fixtures can still run a battery down overnight. Put navigation lights on their own protected circuit. Put decorative and underwater lights on switches you can kill without losing the required lights.
If the panel is already full, the plan may need a breaker or a switch first. That is an electrical question. It is not a reason to stack more lights on one fuse.
A simple order for the project
Work in this order so you do not buy the accent lights first and the required lights last.
- List every fixture and the job it does.
- Replace or repair navigation lights so the required navigation lights are working before operation.
- Fix courtesy lights on steps and gunwales so people can move safely.
- Add deck or spreader light only where you actually work in the dark.
- Choose cabin downlights and linear runs for living spaces.
- Consider underwater lights only after the hull location is confirmed.
- Recheck that decorative lights can be switched off while underway.
Call (954) 375-0100 to talk through your boat-light project
Contractors and charter operators can bring the boat list to the Fort Lauderdale store at 2860 West State Road 84, Suite 114. The counter is open Monday through Friday, 8am to 4pm. The address, hours, and phone are on the contact page. Call 954-375-0100 if you want to talk through a project before you order.
Online orders are packed and handed to the carrier within two business days in most cases. Some items take longer, and we will say so. Delivery time then depends on the service you pick at checkout. Domestic orders ship inside the United States. International shipping is available only on items marked eligible, which checkout confirms. Orders over $100 qualify for free shipping when the order is eligible. The full rules are in the shipping policy.
Frequently asked questions
What boat lights are required at night?
From sunset to sunrise, and in restricted visibility, a power-driven boat underway needs the navigation lights in Rule 23. That is generally a masthead light, sidelights, and a sternlight. Boats under 12 meters may use an all-round white light and sidelights instead. Courtesy and underwater lights do not replace those.
Can I replace an old bulb with any LED boat light?
No. Match voltage, the cutout or base, and the job of the fixture. A navigation light also has to keep the right color, arc, and visibility. If the original part is discontinued, ask for a similar fixture after you measure the old one. There is no single retrofit kit that fits every boat.
Should underwater lights stay on while I am underway?
Turn them off if they could be mistaken for a required light or if they hurt the lookout. Underwater lights are often used at rest or around a dock; if used underway, follow the product guidance and applicable navigation-light rules. Keep them on a separate switch from the navigation circuit.
Where should I put courtesy lights?
Put them low, at steps, gunwales, and walkways, aimed down so they do not shine into the helm. Use a warmer color when you can. Brighter deck and spreader lights belong on their own switch for docking and deck work.
Does Apollo carry its own boat lights?
Yes. Apollo Lighting developed and offers its own line of marine lights alongside other marine brands. The Fort Lauderdale team can help boat owners, marine contractors, and charter accounts sort a project. Bring photos and measurements so the suggestion matches the boat.
Bring the old fixture, or photos of the base and cutout, and the job you need the light to do. We would rather match a similar marine light than sell one that does not fit.