How to Install Underwater LED Boat Lights Part 1: Where to Mount LED Underwater Lights on Boats

This is Part 1 of our series on How to Install Underwater Boat Lights, to continue to Part 2, click here.

In Part 1 we cover how to pick the best mounting location for LED Underwater Lights on your boat during installation. During the video, we look at various Liquid Lumens products and where they would work best on this Supra SL550. After reviewing a few different products and mounting locations, we go into detail with selecting the best mounting location for a set of Liquid Lumens Mavericks Underwater Lights. If you want to skip ahead to one of the key steps in the process, here are the timestamps for the step-by-step:

1:31 – Step 1: Look for a location about 1/3 of the way in from each side of the boat if possible.

1:47 – Step 2: Select a flat surface.

1:51 – Step 3: Be sure lights will not interfere with the boat’s equipment.

2:10 – Step 4: Remove any necessary items or panels to gain access to the bilge.

2:27 – Step 5: Inspect the interior area of the boat before you drill.

2:55 – Step 6: Use a reference point to verify where the drill will break into the bilge.

3:50 – Step 7: Cut out drill template and tape to mounting location.

Now you are ready to begin drilling! Continue to How to Install Underwater LED Boat Lights Part 2: How to Drill Through Gel Coat When Wiring LED Lights on a Boat for more help with your installation, or visit our Installation Instructions page for detailed a step-by-step guide. Comments and questions are always welcome. Let us know how we did and what other content you’d like us to see from us in the future. Thanks for watching!

Transcription of Video

Hi, I’m Rob with Liquid Lumens and today we’re going to teach you how to pick the best mounting location for a set of underwater lights on your boat.  We’re going to evaluate a few of our different products.  The Surfrider model light here is representative of the same size and dimensions as our Skinny Dip light, just different components and a different lens.  And the Pipeline here is applicable to either the Pipeline Single color lights that we sell, as well as the RGBW configuration.  The footprint of these two products is actually the same.  They are both right around 4 1/2” in diameter.   As you can see the height and thickness of the housing is varied between the two products.  The thicker housing in the Pipeline, the RGBW allows us to project a little tighter beam angle lens and get you a brighter candela rating off of the light.

As you can see, we’ve removed the factory lights.  We’re going to have to drill some new holes for the bolt hole pattern on our product.  If you’re replacing some factory lights, you’re going to want to reuse as many holes as you can or cover up the old existing holes.  By checking our Surfrider model light or the Pipeline light, we’re able to see that we can cover the whole bolt pattern of the factory light on this boat.  There’s a paper drill template that would come with your set of lights.  We wouldn’t be able to reuse either screw hole in this case, but we can at least cover up the factory pattern so you would never know the factory lights were there.

Let’s walk through a couple of other options if we had a clean boat with no factory lights on it.  In some boats, in the past, we’ve seen customers try to mount their lights out here on the hips of the boat.  

STEP 1:  Look for Location One-third of the Way in from Each Side of the Boat

We prefer to mount about a third of the way in from each side if there is real estate available.  That leaves us this area here.  We have a little bit of a seam in the gelcoat here, so we would likely mount here or here.  

STEP 2:  Select a Flat Surface

We don’t want to go too low because as the surf tabs are actuating and coming up, we don’t want them to risk bumping into the light or blocking light and creating a shadow in the water.  

STEP 3:  Be Sure Lights Will Not Interfere with the Boat’s Equipment

If we can go a little bit higher, about here, we’d be able to clear this surf tab or here.  Other lights, like our Mavericks light, we’ve seen them mounted both here and also vertically here.  

Inside the back of the Supra SL, there’s a surf locker and you can see inside the locker there is a plastic panel to help drain water out of the interior of the boat.  

STEP 4:  Remove Any Access Panels to Gain Access to the Bilge

We’re going to remove that panel so we can see the inside of the transom area of the gelcoat where we need to drill holes.  

STEP 5:  Inspect the Interior of the Boat Before You Drill

Here’s a little bracket that had some wire and tubing zip tied onto the back of it.  We’ve already snipped the zip tie and we’re going to move it out of the way and zip tie it over here to these other hoses in the engine compartment while we’re drilling holes just to make sure we’re clear of anything and we won’t damage any of these items inside the boat.

If we look along the back wall, you can see that one tube and that one wire harness are the only two items back here that we’re concerned about.  It’s a pretty clean open space in the Supra.  One thing we always like to do in picking a mounting location is find an object in the back of the boat that you can reference  on the exterior.  In most cases, that’s going to be the exhaust port.  We can see the exhaust port down there with the clamps on it.  By measuring where we intend to mount the light on the exterior of the boat in reference to that flange on the exhaust port or one of the bolts we can then come and measure in the interior of the boat and verify that we see where that hole is going to come through so we don’t drill into something we don’t want to.  

STEP 6:  Use a Reference Point to Verify Where the Drill will Break into the Bilge

This is more or less the mounting location we have selected for the light.  By referencing the flange on the exhaust port we can see, we’ll call it an inch and a quarter between the bottom of the light and the screw.  We know that none of our drill holes are going to be lower than an inch and a half off of this bolt on the flange here, so if we measure an inch and a half up from that in the interior, verify there’s nothing there that we’re worried about, we should be good to start drilling holes.

STEP 7:  Cut Out Drill Template and Tape to Mounting Location

We’ve prepped the exterior of the boat, we’ve prepped the interior of the boat, we know we’re good to drill.  We’ve now cut out our drill template that was provided with the installation kit and we are going to pick our best mounting location here.  We clearly want to reuse this hole because it’s a big hole and it’s going to be right in the vicinity if we’re able to.  The wire hole locations on this drill template are here and here.  We’ve measured them and they are just about one and three-quarter inches apart.  We got lucky because on this Supra, as you can see, if we go to one and three-quarter inches we’ll actually be able to drill out this hole a little bigger for one of the wires on the Mavericks and the other wire is going to fit into the existing hole that was already on the boat.

A couple of things to keep in mind when you attach the drill template to the boat.  First of all, never use a level when checking the position of the drill template on your boat because the boat may not be level on the trailer and the trailer may not be on level ground.  This is more of a visual alignment or you can measure off of other reference points on the boat to make sure the lights are equally spaced and equally level to the position you want them in.  Now we have the template positioned where we intended to drill, but we’ve run into one issue, so we want to explain some things that you need to look out for.  It looked good where we could reuse the interior mounting hole from the factory light, and we have this large opening behind where this hole is going to go, so we were going to go with those two holes, however, we can see that there’s a little bit of a radius and a curvature on the back of the boat right here that we’re going to be butting up against.  What we want to avoid is, if the light is butting up against that radius, it’s going to lift it off the boat just a hair and prevent us from getting a good, water-tight seal on that upper edge of the light.  So, we’re going to offset it down just a hair.  We’ll end up moving this hole down just a little bit, but we’re going to be drilling a bigger hole here than what exists so we’ll end up consuming that hole anyway in the process and it should be just fine.

Continue to Part 2 – How to Drill Through Gel Coat