So I've been working on this post for a few days now, and think I have it pretty detailed. I typed it up in Word, so I just copy and pasted it here. I may have to fix some typos here and there, but this should be enough to get you in trouble. If you have any questions or need pictures, please reach out to me here, through messenger. I'll take pictures, measurements or provide any insight that I can. If you're not comfortable running some of the tools needed, consult a professional or someone who is. I used a table saw, full size router, heat gun, cordless drill, and various hand tools. Safety gear is essential' ears, eyes, hands, dust mask. ***I'm not responsible for anything you tear up or destroy on your rig.***
I didn’t do much in the way of a “how to” picture wise, but I did want to give those who choose to tackle this task a little bit of confidence. I measured and measured and measured some more. Cutting holes, BIG holes, in a brand new boat is nerve racking! I couldn’t find a whole lot, but what I did find was helpful, even though it created a lot of doubt. The members I reached out to were extremely helpful and accommodating.
The head unit:
I chose a JL Audio MM-100-BE for my head unit. I like to have a rotary knob for volume, plus the option to balance/fade, and adjust treble and bass. This unit does all of that and a lot more. It is also is NMEA2k compatible, so I can display the data from the head unit onto my Garmin. Besides that, this unit has 8 pre-amp outputs and each pair has 4 volts, this is GREAT for pushing a lot of signal power into the amp, allowing you to use minimal gain on the amplifier, which can introduce noise and static. The unit came with a nice template made out of thin cardboard, and fits the unit perfectly. My boat came factory rigged with the Garmin 7610 on the port side of the console, and the VHF low on the starboard side. This made the obvious location for the head unit to be above the VHF and beside the Garmin. I taped off that area with 2 layers of painters tape and found the center of the VHF. I decided to run the top of the head unit in line with the top of the Garmin. A simple straight edge produced this line. I lined up the center of the template with the center line of the VHF and taped it into place. I also took a marker and marked this cut out in the event I tore up my template. Now to cut. I decided to use a Dremel with a tile cutting bit. This section of the console is 3/8” - 1/2" thick and foam cored. Drill a hole here to accommodate the Dremel bit, and get after it. BE PATIENT AND CUT SLOWLY! I’ve used a Dremel a lot, but never with this bit or for this purpose. I found it to be much like writing with a pencil….precise, easy and, well, slow. When I was done, the unit fit perfectly snug, no wobble or issues. I drilled the necessary holes (small pilot and then final size) for the unit and screwed it in BY HAND. Wiring it up is simple. There are factory power, ground and memory wires present. This unit does not have a memory wire, so I put a piece of heat shrink over that wire (it is hot) and cable tied it out of the away.
I knew the amp I had was going to fit the best and how I wanted it to, on the port side where the dealer installed the battery charger. I wish I had a chance to speak to them prior to this, as I would have had it done differently or just done it myself. The walls of the console are only about ½” thick, maybe a tad less. I like more bite than that and I refuse to put screw holes on my console….well for that anyhow. The dealer is hot on using PVC sheet and epoxy for a mounting board. This sheet can be found at my local Home Depot and is inexpensive. The epoxy they recommend is methacrylate. Devcon, Plexus, and many others have this. I found it at my local Ace under Devcon Plastic Weld; read the ingredients and make sure it has methacrylate in it. This stuff sets up in 5-6 minutes and cures within 24 hours.
I knew I was going to move the battery charger to the starboard side, and that the existing piece of PVC board on the port side was a done deal. So my option was to make another piece and mount it above the existing piece that the dealer installed. There was room there and I need to use all of it….maybe another amp in the future or an ACR or charger. Who knows? Anyhow, rather than just cutting a piece for the amp and epoxying it into place, I decided to catch the bolt for the grab rail, too. Maybe it looks funny but I know it’s not going to fall off the side of the console. I measured out the dimensions I had to work with and laid it out on a piece of ½” PVC sheet ($27 for a 2’ x 4’ piece) with a combination square, tape measure and pencil. This stuff is EASY to work with and not too messy, light too! Once I had my rough piece cut, I test fit it in the boat. Good to go. Make sure the amp is going to clear the cup holder and other stuff in there, which mine did. To mount the amp, I knew I wasn’t going to simply screw it in. I like pointed (spiked) “T” nuts. These mount on the opposite side of the panel you’re mounting too, and gives superior holding strength compared to plain jane screws. Lay them out accordingly and remember, the back side of the panel. I like them to be flush, so I make a small pilot hole from the front side (actual amp location) and then flip it over and use a spade blade as a counter sink. You need material here to grab the point of the spade blade, so don’t drill the big hole yet. Once you have them flush (test the depth with the bottom side) drill the appropriate size hole. I go a size small, so it has to be tapped in with a hammer. I also use a dab of epoxy on to keep them in place. Let me tell you something, that epoxy will tear PVC out before it breaks loose. Ask me how I know….As for the grab bar bolt; it had a 1” fender washer and I wanted it flush too. Before I drilled the ¼” hole, I made my pilot hole, then used a 1” spade blade to counter sink it the fender washer. Nothing to it. I did have to make a run to Ace for a ¼-20 bolt that was ½” longer…I think it was .12 cents. Make sure it’s stainless. A few rows of epoxy, run the bolt in, level it up and you’re done….I held it in place for about 6 minutes with light pressure. I let it set up overnight and then mounted the amp the following evening. **Test fit the amp to the board if you do it this way. You’ll need to ensure the t-nuts line up properly with the mounting holes in the amp. There isn’t really any wiggle room for misalignment. Do this before you epoxy it into place.**
I always use the manufacturer supplied speaker template (JL uses a nice thin piece of cardboard - better than flimsy paper) and ALWAYS test fit it to the speakers in the box before you do anything. The whole measure twice (ten times) cut once thing. I make my templates pretty, well, over the top probably. I ALWAYS make them square and on a dimension that is easy to find the half way point, or any other reference point you may need. So for the 8.8, I made a 10” square (no 9-7/16” type stuff) out of 1/24” MDF. This allows me to mark center vertically and horizontally; think crosshairs. Once I have the MDF cut to square on the table saw, I mark the center of the square…draw an “X” from corner to corner and you’ll find the center. I usually don’t mark across the whole piece, but I needed to on this for reference points for the screw holes. I know, I have issues. You should have one set of screw holes that are on the same horizontal plane as the center of your MDF template, which is perfect! This allows you to square up the speaker in the template/jig, which puts the JL logo nice and level. Now I lay the speaker hole template on the MDF square and eyeball it into place. I center it up with a simple combination square, ensuring I have the same reveal on all 4 sides, and make small reference lines. Then I spray glue the supplied speaker template and place it onto the MDF accordingly. Now for the SLOW and easy cut. I use a jig saw to cut the circle, and sand accordingly. My template looks out of round in this pic, and it might be a tad. It fit the speaker well, and anything you do to remove this material to make it perfectly round just unnecessarily opens up the speaker hole. Refrain from making it perfect or be prepared to make another jig. I do have a circle jig for my router, but knew I could get it close enough with the jig saw. I did.
Now onto the boat end of things….The front of the rod lockers:
At first measurement, I didn’t think the 8.8’s would fit up front due to the depth of the magnet. My tape measure told me they were going to hit the rod lock liner, so I took the steps to accommodate this interference (skip this because they do fit without spacers or cutting the rod locker liner- Josh B on this forum had to cut his locker liners on his 2016). Laying out the location is simple. Tape the area off with masking tape or painters tape. I use 2 or 3 layers of tape for scratch protection and marking up with measurements. I wanted the speakers to be centered in the front rod lockers. I pulled center from the edge of the gunnel rather than from under the gunnel. This centers the speaker up in a more eye appealing way. Once I found the center planes, I extended my “crosshairs” (you see where this is going, right?) vertically and horizontally, with a small level and then placed my MDF template on the tape and lined up the crosshairs with each other. A few things should happen here….the horizontal screw holes should hit the horizontal line, the square sides of the template should be level; top and side. I hold this in place and use my cordless drill to mark a couple of speaker holes (usually 90* from each other, but not side by side). I set the template down and drill those two holes and then size up to whatever drill is needed for the supplied speaker screws. Mount the template into place and drill the remaining holes in the same manner; pilot and then final size. I DO NOT use a screw gun or drill to tighten these screws. I use a regular screw driver and run them up snug, by hand. I cut my holes with a router, so I counter sink the screws because I follow the template. If using something else to cut the holes, you may not need to counter sink the screws. Now it’s the point of no return….drill one hole inside the template and into your prized possession, upsizing as you go. In my case it was from a 5/64” pilot to ½” final, this would accommodate my router bit. Drill this hole close to the edge of the inside of the template, as it’s just less to cut with the router. Insert the router bit, turn on the router and get with it. I wear double hearing protection, quality safety glasses, and a mask (I wet the mask. If you have a painters mask with cartridge filters, even better). Not that you want to make out with your router, but I get down close and personal to make sure I doesn’t walk out of the template. This PPE makes it a lot more comfortable with a machine turning 30k rpm. Make your cut in the direction the router wants to go, and then power it off. Keep your hands on the router until it stops, before setting it down. This avoids any unwanted nicks or cuts in the boat or YOU. I also place a vacuum cleaner nearby and have suction near the hole I’m cutting. This does not come close to catching all the mess, but it helps a little bit. You’re done. Check fitment and go about installing your speaker.
The rear bulkhead:
With the live well and two release wells close by, this is the trickier of the locations to mount such a big speaker. There’s room! And as for rigging, be cautious of the raw water wash down hose (starboard) and if you have it, the fresh water wash down hose (port). They run low and should be out of the way. Other than those hoses and the liners for the release well’s, you’re in good shape. Measure, measure and measure some more. Following the curved shape of the rear bulkhead in the 23, it’s obvious as that the more you move outwards, the sharper the angles the speakers will go in on, pointing the basket and magnet further away from the release well liners. Not one to cut holes and look around and cut more holes. The solution, for me, was to mount the speakers as close to the rod tubes as possible, without overlapping them with the speaker. This required me to modify my template….I inserted a speaker into the template and traced the outer edge of the speaker onto the template, and then cut that section out. I guess I went about ¼ way around the speaker, but only on one side. This was the easiest way to show me how much room I had before I overlapped the rod tubes. When doing the other side, flip the templet over. I had to cut off a “dog ear” to allow clearance for the raw water wash down outlet, which is why my template looks jacked up now. I was throwing it away anyhow…..Also, you only need the vertical center (horizontal line), as horizontal (vertical line) is going to be determined by how close you can get to the rod tubes. Line up the screw holes on the horizontal line, same as before and double check with the level on the top and side. Repeat the process for cutting the holes. I always cable tie the slack end of the speaker wire to a “leg” on the speaker basket. This takes the slack and weight of the cable off the terminal….helpful for keeping the connection over boat wake and chop. I also coat the connections with Vaseline, to keep corrosion at bay.
I do a few more things, but if you’re still reading this, you needed this post! I clean up the inside of the holes with sandpaper. This is going to help save your arms when you’re fishing speaker wire through the hole. Before I reach in there feeling for the speaker wire, I run some tape around the edge of the speaker hole. This helps to minimize the itch you’re going to get from the glass… but it’s not 100 percent. The newer boats are pre-wired from the factory in the obvious locations most would mount a speaker. The drill bit is going to chip the gelcoat a little bit. I initially run the drill slowly to minimize the chipping. I also use a piece of marine heat shrink (with the glue inside) on the speaker terminal to the wire. This just helps keep things together. Also worth mentioning, the JL speakers use a smaller than “standard” small spade terminal on their negative wire side. The positive terminal is the standard larger size that most bus bars use. This may save you a trip to the hardware store.
I hope this helps at least one person out. My local installer quoted me 12 hours at $100/hr. to mount and wire the amp, install 4 speakers (with factory ran wire) and installing a JL Audio head unit. I made the amp mount, cut the dash for the JL MM-100-BE, and did all four speakers in less than 8 hours. I’m not a pro, but have wired up plenty of car stereo’s.
**NOTE** Horizontal and Vertical can be a little confusing, I suppose. The actual lines will be that, horizontal and vertical, but they will locate opposite of what they are….The horizontal line is used for the up and down location; vertical. The vertical line will be used for the side to side location; horizontal.