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Do-It-Yourself Underwater Lighting

Underwater lighting is not just for superyachts anymore.

It used to be that underwater lighting was something that you only saw on large yachts but that is rapidly changing.  More and more these days, you are seeing smaller recreational boats with colorful lighting below the surface.  There is one thing to consider though, the cost.  Whether you buy a new boat with underwater lighting installed or add it on after the fact, it can be a rather expensive option for just a little bling.  There is another option, however.

When I decided that I wanted to add some light below the surface on my boat, there were two things that I was not comfortable with when considering the traditional method.  The first was the cost.  At over 2 thousand dollars for hardware, wiring, labor and lifting the boat out of the water, the cost was hard to justify.  The other thing that I was not comfortable with was the fact that I had to drill holes into the hull.  Sure, a boat hull already has holes for various purposes but I was not trying to add more!

I spent some time looking for other options and stumbled across a solution that I was willing to try, an underwater boat plug light.  It replaces your drain plug by screwing into the hull where the drain plug normally goes and then is wired into the electrical system of your boat.  Light is provided by one or more LED’s and they come in many different colors.  Some units can also change colors as well.  
A boat plug light is an easy way to add some bling to your boat.

When I did my research, I found several options on Amazon, Ebay and even some marine supply websites.  The power ratings typically ranged from 5 watts to 35 watts and they came in varied sizes and LED configurations.  If you decide to get one, just read the specs carefully, I swear I saw some units for sale that looked like they were made in someone’s garage.  I ended up purchasing one that emitted a blue light and consumed 27 watts (which is pretty bright for an LED).  One of the big factors in me choosing the unit that I did was that it had an IP68 rating which means that it is dust proof and water proof over a prolonged periods of time.  This may seem obvious but to me, I would prefer a unit that has been certified to be waterproof over the long term rather than one that the manufacturer just says won’t leak.  If you decide to purchase underwater lighting, I would highly recommend choosing an option with this rating.  The light came with about 15 feet if wiring and a built in fuse.  At a cost of just over $50, I figured that I was willing to take the risk to try it out and see how well it worked.
A boat plug light screws right into the drain plug hole

Installation of the light was easy.  Obviously, the boat has to be out of the water so you need a trailer or a lift.  In my case, The Bear’s Den II had already been lifted out of the water for some other work and it was sitting on stands in the boat yard so there was no extra cost involved.  I took the drain plug out, screwed the light in and then jumped into the bilge to finish the wiring.  Rather than running the wiring all the way up to the helm, I decided to purchase a wireless controller from Amazon for another 18 bucks.  Using the key fob that comes with it, I can turn the underwater lighting on or off from anywhere within 75 feet of my boat.  
I purchased a wireless controller to make the wiring easier.

When all was done, I had a pretty cool underwater lighting system for my boat for less than a hundred bucks.  Yes, I have seen many boats with 3 and four light underwater lightings systems that outshine mine but I also know what they paid for them.  Mine easily illuminates the water up to 20 feet behind my boat and I can leave it on all night without killing my batteries.  When underway, the reflection off of the turbulent water behind the boat also illuminates the water forward of the stern for a really nice effect as well.  

My light looks great when the boat is at rest and underway.

In conclusion, this project was a simple, low cost way to add a little pizazz to my boat.  I could have spent a lot more money for a more complex system that would perform better but I really don’t think that was necessary for me.  I’ll use the money I saved to buy fuel.

Happy Boating!

Captain Frank
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  1. Very well written article.

  2. how cool is that, it looks like fire

    1. I know. I did mine in blue but I have a friend that has a red and white Donzi and he used red lights. Looks awesome!

  3. How twisted does the wire lead become from removing to drain bilge?

    1. I actually pre-twisted it in the opposite direction a bit to allow for unscrewing the unit when needed but either way, I think it would not be an issue as long as you don't restrict it too much when tying it down etc.

  4. Just friendly remimder. Runni g with underwater lights on is dangerous and Illegal.

    Very cool at anchor or docked though..

    1. There has been a lot of confusion on this topic and the laws do vary a bit from location to location. In general, law enforcement will typically have issues with ANY type of lighting on your boat that potentially interferes with another boater being able to interpret your navigation lights or any lights that make it appear that you could be a law enforcement vessel. Therefore it is wise to keep this in mind when choosing what type of additional lighting to use as well as how bright it is.


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