Underwater Lights

In our inaugural Ask The Experts column, we turn to the professional marine electronics installers at Electronics Unlimited based in Ft. Lauderdale, for advice on underwater lights – the latest ‘must have’ accessory for boaters across the state. Stay tuned as in subsequent issues; we’ll be contacting maritime attorneys, FWC officers, tackle manufacturers and a variety of other experts for answers pertaining to questions in their respective fields. What would you like to know?


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At sea or at the dock, underwater lights have become increasingly popular. Photo: Sea Vision by Underwater Lights USA

You’re probably well aware that underwater lights have become extremely popular these days. If not, all one needs to do is take a casual stroll down any dock at your homeport under the cover of darkness and chances are you’ll see at least a few boats outfitted with underwater lights. Actually, boat owners around the world are requesting underwater lights for vessels of all shapes and sizes. Because of this recent trend there are now a plethora of lights available from a wide range of suppliers. Our goal with this installment of Ask The Experts is to shed some light (no pun intended) on the differences between the overwhelmingly large number of underwater lights and which is the best choice for your particular application.

Installation is not difficult but does require some important considerations and should always be left to a professional…

Basically, there are two types of underwater lights available – LED (Light Emitting Diode) and bulb. Since the turn of the century, the popularity of underwater LED lighting systems has exploded within the marine industry. Most LED lights are available for thru-hull mounting and surface mounting applications. Recently, manufacturers have also designed lights that can be mounted on your trim tabs as well as in your standard ½-inch garboard drain. One of the major benefits of LED lights is that they require less amperage to operate, which translates into a longer lifespan as well as the requirement of smaller gauge wiring. Another factor to take into consideration is that LEDs are available in a rainbow of colors and if you so desire, you can also incorporate a strobe effect. The biggest disadvantage LED lights have is that once installed, if the light malfunctions, you must remove and replace the entire assembly. This cannot be done while the boat is in the water, so if you don’t keep your vessel on a trailer or on a lift, this can be a costly experience.

Bulb lights come in three variations. The first is a standard bulb that is very inexpensive and only provides minimal light. For mid-sized boats the most popular choice is Xenon. This is the same type of lighting technology used in the headlamps of high-end vehicles, and these lights generally cost 50-percent more for the same wattage as standard bulb styles. The reason these lights come with a higher price tag is because they shine extremely bright. The last type of bulb is a metal halide. This is a very popular option when it comes to high-end applications, as metal halide bulbs are some of the brightest lights available.

One major advantage of a bulb style light is that they are installed via thru-hull fixtures and are able to be serviced while the boat is in the water, thus eliminating the cost of a haul out. You can also change the color of the light by placing a piece of colored glass on the inside of the lens.

Regardless of which light you choose, placement is very important. Be honest with yourself about what expectations you have before making a final decision. If you’re strictly interested in a visual effect, then you will most likely have your lights installed on the transom. Most anglers have their lights installed pointing down and use a wide range of colors with white and blue the most popular. Regarding spacing, leading manufacturers recommend a minimum of three-feet of separation between lights.

Installation is not difficult but does require some important considerations and should always be left to a professional, especially when you consider holes must typically be drilled in your boat. The most important thing is that the lights are installed with a marine underwater sealant like 3M 5200. As you may already know, water intrusion can have a devastating effect on your hull and should be avoided at all costs. Before making any final decisions on underwater lighting, be sure to do some homework and speak with your local marine electronics distributor for additional advice.


  • Due to the heat that may develop, underwater lights should only be illuminated when your vessel is in the water.
  • Consult with your boat manufacturer to see if they have any reservations about the hull warranty in regards to underwater light installation.
  • Underwater lights start their operational lifespan at peak performance so if you replace one light, you should replace them all to maintain an even effect.

Underwater Light Manufacturers