Installing A Sounder

[Fishing Rhino]

I'm particularly satisfied with the mounting of the GPS puck at the bow of my boat.

My prime consideration was to have it where it would have a clear view of the sky. That meant it could not be mounted near the console or the motor. The configuration of the console eliminated the possibility of mounting it at the console on an antenna extension as I did on my Z-7. One of my fishing buddies was always teasing me about having the puck mounted on the two foot mast. In my defense, there is a reason that Humminbird provides a threaded flange which can be bolted to the puck to do just that.

I settled on installing it at the bow, on the panel for flush mounted sonars. The problem is that the surface is angled so the sonar will face the bow angler. My solution was to make a disc out of black gel coat impregnated with small pieces of mat torn from scraps. Fortunately, the cups I use for spraying gel coat were the perfect size. Poured just over an inch of black gel coat in the cup and catalyzed it. Then the small pieces of shredded mat were pushed into the gel coat with a paint stirring stick, and pushed around until the mat was thoroughly distributed in the gel coat.

Once cured, the cup was peeled away, and what remained was removed using a belt sander clamped to a table top.

The boat was levelled using a long level on the front platform. Boats rarely sit level on the water. They may list or sit down by the bow or stern. Since a boat is dynamic, and not static, it is not necessary to be absolutely precise when tapering the disc to make its top level. I used a short mason's level, and as long as the bubble was between the lines it was good enough.

After the disc was tapered to be level, it was hand sanded, including hand sanding a radius on the top edge. A hole was drilled in the center, and the two mounting holes were drilled. The threaded flange that came with the unit was used to drill the two mounting holes. Here you need to pay attention. The mounting holes on the puck are at each end of the HUMMINBIRD name. For a neat install, keep that in mind before you indiscriminately drill the holes. The thin edge of the disc will be toward the bow, the thick edge toward the stern. The holes should be at the sides of the disc.

Once finished, the puck got sprayed with flat black prior to final installation. For installation, a small bead of black silicone was applied near the edge of the bottom surface. The puck was then set in place using bolts to get it in proper alignment. Just enough pressure was used to cause the silicone to bulge out at the edge of the disc. It was then allowed to set up before finally bolting the entire assembly together. Because the silicone is glossy, I got an artists brush, sprayed some flat black onto a piece of cardboard , then painted over the glossy black.

Three angles of the "trial fit".

The finished install.

To layout the components that mount on the fiberglass surfaces, I covered those areas with masking tape. It allows parts to be moved around without damaging the gel coat, and can be marked when the final location is determined.

Some hints about drilling through the gel coat. Use a small drill to make the initial hole. Then, use a countersink bit. Countersink the hole until the diameter of the countersink is just a tad larger than the hole you intend to drill. It will eliminate the problem of gel coat chipping and fracturing that will otherwise inevitably be caused by twist drills.

For the larger holes, use the paddle type bits that have a spur on each edge. That spur will cut through the gel coat without fracturing it. The masking tape will also help in that regard, though by itself it will not prevent the chipping of the gel coat.

Here's my finished project.

[Wayne P.]

You wasted a lot of time and effort with the antenna mounting. Some install the GPS antenna inside the hull at the bow or at the transom depending on where the transducer is located.

Why did you put it on the bow?

Is your SI transducer on the transom?

If the transducer and GPS antenna are at opposite ends of the boat, you have a built-in error of the boat lenght for waypoints determined by sonar returns.

[Fishing Rhino]

I put it on the bow because the instructions stated that it should have an unobstructed view of the sky.

"To optimize performance of the GPS receiver, mount it in an area that has full exposure to the sky. The effective area of reception is 5 degrees above the horizon."

You are correct about the built in error. If I drop shot over a school of fish, the guy in the rear has the advantage.

[Wayne P.]

That full view of the sky refers mostly to boats that have a metal canopy or some other overhead structure that blocks radio frequencies. Some think that antenna is a satellite dish, it isn't.

The accuracy of the antenna is one of the best features of the units. I and many others get 2' EPE.

The display mount looks quite sturdy. I use the ball type RAM mounts.

Once you get familiar with that technology and decide you want the same at the bow, you will already have the antenna in the right place for that. It is a great fishing tool as well as a search tool.

[Fishing Rhino]

Mostly, I use the GPS for two things, returning to waypoints that have been productive and for finding places of interest on unfamiliar waters, be they coves, points, shoals or whatever. I do plan on getting a bow unit, but not right away. Need to recover from the cash layout for the new boat, the 898, and countless other odds and ends.

I guess satellite transmissions vary according to their types. I'll lose my XM station if trees or buildings are in the line of sight from my antenna. Rain and snow shut down the satellite tv signal. I know I got some satellite signals and a fix when my other boat was in the garage, but it would show transmissions from more satellites when the boat was moved outdoors.

It's just me being anal about optimizing anything, in this case the Humminbird puck.

[Fishing Rhino]

I used the ball mount on the other unit. It had the 2.25" diameter balls. They are available here and there, but nationally, they are on back order until April 15th. It was a nice unit, but the Ram Swing Arm I got cost forty dollars less, and it is rated to support 60 pounds. The downside to the mounting bracket is that it is a universal mount. It can be clamped to a vertical tube and has a variety of holes and slots. I used oval head machine screws 5/16" at the bottom, and 1/4" carriage bolts for the top two fasteners.

The upside is that until I get the bow unit, I can loosen the pivot at the console and swing the Humminbird 180 degrees to face the bow, should I want to.

It is available with a mounting bracket that can be attached to horizontal surfaces.

[Wayne P.]

I saw the mount you have at a Gander Mt. a few days ago that had the rail clamp. You did a good job with that install.

[Fishing Rhino]

I wish I had looked at it a while longer. I could have cut an inch off the bottom and ended up with the carriage bolts on the bottom and the oval head machine screws on the top. It would have been flush with the step in the side of the console. It does keep the cables out of harm's way, and they are supported by that step.

I did turn it on after connecting it to the power with a fusible link and a 3 amp fuse. It did acquire its position within 28 feet in spite of having a ceiling, roof and some overhanging trees in its line of sight. Next time, if there is a next time I'll probably mount it as you suggested, below the deck.