Electronics, GPS and VHF, Part 3: Construction of the Mahogany Panels

The mahogany panels, custom cut for the Garmin GPSmap 541s
Those who upgrade their electronics often find that their new devices do not fit their old holes. The new device is either too large, too small, or simply not the same shape as the old one. In these circumstances, the sailboat owner is faced with two choices - either he can fill the existing hole with fiberglass, and then cut a new hole, or he can cover the existing hole with a panel of wood or plastic, and then cut a new hole through this panel. The primary benefit of the first option is that the new hole will be just the right size. This, of course, will allow for a nice, well-sealed fit. The downside of this option is that the filling of an old instrument hole can be a time-consuming chore, and it can be one that has less-than-pleasing results, unless of course the surface is well-faired, well-sanded, and well-painted. In the refitting of Oystercatcher, my Ericson 25, I had no plans to repaint my deck. Therefore, I decided that the filling of the old instrument holes was not a task that would be wise for me to undertake. Accordingly, I opted to create a panel to cover these old holes. From my standpoint, the panel would serve two roles - one practical and the other aesthetic. First, it would serve as a sturdy surface for the mounting of the device. Secondly, it would serve as an attractive trim piece. In other words, it provide an aesthetically pleasing frame that would not only accent the shape of the device, but also complement the mahogany found elsewhere on the boat. In this posting - the third of seven - I describe how I created these mahogany panels that would cover these holes.
As is often the case, I started this little project with a cardboard mock-up, or I should say mock-ups. I didn't take any pictures of these mock-ups at this stage in the game, but I can say that it took a good bit of cutting and re-cutting to figure out their proper size. The exterior panel had to be big enough to cover the two holes, but it couldn't be too big. Otherwise there would be problems matching it up with the interior panel. What do I mean by this? Well, the exterior side of the cabin trunk is completely flat.
The interior, however, is not. There is a piece of fiberglass which runs the length of the companionway - sort of like a lip. On this fiberglass lip there is a piece of teak. It forms a frame of sort along the side of the companionway. As you can see in the picture below, this frame is not far from the instruments and thus the instrument holes.
Satisfied with the mock-ups, I cut the two panels to the appropriate sizes. Note that the one on the right is slightly longer. This is the interior panel. I wanted it to be slightly longer so there would be plenty of wood for the washers and nuts, which would be on the interior.

Next, I drew reference lines on the exterior panel. These would help me in the drilling of the holes for the screws, and in the cutting of the hole for the GPS.
For the drilling of the holes, I used a screw-set, i.e., a bit that allowed me to drill each hole and countersink each hole, all in one step.
I drilled and countersunk the first hole, at the top of the panel. Before countersinking all of the other holes, however, I put the GPS template down, just to see how much room I had to work with. As you can tell from the picture below, I had very little. Ideally, this panel would have been about an inch wider on each side, but as I said, I was restricted on the interior of the boat by the frame around the companionway.
Why so many screw holes you might ask? Well, I had to make sure that this panel would form a nice, water-tight seal around its edge (with, of course, the proper sealant applied).
You might also ask why I would situate the GPS on the upper end of the panel rather than in the middle of it. All I can say is that, to me, this looked better. From a practical standpoint, it also meant that the backside of the GPS on the inside of the boat would be slightly higher and thus more out-of-the-way.
The template provided with the Garmin flush-mount kit (which I purchased independently of the Garmin GPS) was helpful. Unlike many other templates I've used for other things I've purchased for this boat, this one had a sticky back. It also had clear instructions on where to drill holes and cut holes.

Given that this piece of mahogany was only about 3/8 inch thick, I had to be especially careful, when cutting the hole, not to apply too much pressure with the jigsaw. This mahogany was tough, and I doubt I would have broken it, but why tempt disaster? For more on the type of mahogany I used for this project, see my article, "Companionway Hatch Construction." See also the Label on the homepage for "Southern Lumber."
The Garmin, flush-mount housing fit just right in the hole. Note the rubber bezel around the housing.
The GPS dry-fitted with the cover in place.
Keep in mind that throughout this process, I had not yet screwed the panel into place on the face of the cabin trunk. When the time arrived for me, at last, to screw it into place, I began with the hole at the top of the panel. This allowed me to pivot the panel to achieve a level position.

The interior as it appeared after I had drilled all of the holes.
Now it was time to make use of the cardboard mock-up once again.
Having partially installed the exterior panel, I could now get a good sense of how exactly the interior panel could fit against it. The screws from the exterior provided precise points by which I could orient the interior panel, or I should say "mock-up." Notice that in the picture below I have trimmed the mock-up on the top right corner so that it will fit within the frame of the companionway.
Using the mock-up as a guide, I trimmed the interior panel to size. Then, I clamped the exterior panel to the interior one, and scribed the cut-out for the GPS housing.

Afterwards, I dry-fitted the interior panel. It just barely fit. Nevertheless, it did a great job concealing the original holes. It should be clear now why the interior panel was necessary. Without it, the installation of the GPS would have look shoddy, and the hole, through which it would have been mounted, would not have been as sturdy and well-supported.
The construction and installation of the exterior and interior panels had brought this project much closer to completion. It was still necessary, however, to cut out the two layers of fiberglass between the two panels, so that the GPS housing and the GPS itself could be situated within the panels. This next part of the project is the subject of my next posting.
This ends this posting on how I constructed the mahogany panels for the Garmin GPS that I installed in Oystercatcher, my Ericson 25.

Electronics, GPS and VHF, Part 2: Analysis

The Garmin GPSmap 541S
When a person decides to add a GPS to an old boat - a decades old vessel that he is refitting - he must also decide where to locate this electronic device. Unlike those with newer vessels, who might be fortunate enough to be able simply to replace an older GPS with a newer one in the same cut-out or hole, those with older vessels often must create a new cut-out or new hole for the new electronic device. Likewise, they must consider how they will wire this new electronic device in the most efficient and tidy fashion. If they are also adding a new VHF to their boat, especially one that will be integrated with the GPS in order to establish DSC (Digital Selective Calling) capability, then forethought with regard to the placement and the wiring of the GPS is even more important. In the refitting of Oystercatcher, my Ericson 25, I had to take these and other factors into consideration when installing a GPS and a new VHF with DSC capability. In this posting, the second of seven in my series on this subject, I describe how I reached the conclusions I reached with regard to the placement of these new electronic devices.
I purchased my Ericson 25 in the fall of 2009 from an elderly person who had kept the boat for years at his own private dock in the Pamlico Sound area of North Carolina. This man, only the second owner of the boat, had been vigilant with regard to the bottom-painting of the boat. As far as the many other areas of the boat and the systems of the boat were concerned, however, he had been neglectful.
Two areas or systems that were especially lacking with regard to maintenance were the electronics and the electrical system. I addressed the electrical system in my earlier article, "Electrical, Original." Let's, therefore, focus on the electronics. On the starboard side of the companionway, one of the two previous owners had installed a depth sounder and a knotmeter. The depth sounder worked . . . well, sort of. It at least would light up, when you flipped the switch. As far as reading the display was concerned, this was next to impossible, unless you cupped your hands around the bezel and put your face about three inches from the screen. Whether or not the information provided was accurate, I have no idea. The knotmeter? It was completely shot.
Opposite the depth sounder and the knotmeter was the compass. This was not, of course, an electronic device. Since, however, its location had to be taken into consideration when the time came to install the GPS and new VHF, let's mention it briefly right here and now. This compass, like the knotmeter, was entirely defunct. The fluid within it had long ago leaked out, and its lens was so bleached out by the sun that it would have been impossible to use the compass, even if it still contained its liquid.
The backside of the compass was on the cabin trunk inset, on the port side of the galley. You can just barely see it at the top of the picture below. Beneath this cabin trunk inset was the bulkhead. On this bulkhead were located the original battery switch and the original DC distribution panel.
I would later remove this battery switch and distribution panel. In their place, I would install new ones, and I would install other new components in a new configuration.
Below we see a picture of what this port side of the galley looked like after I had installed the new components. For more on this subject, see my numerous articles organized under the heading "Electrical" in the Index for this website.
As I was saying, before I went on this brief digression concerning the compass and the port side of the galley, the starboard side of the cabin trunk is where the old depth sounder and knotmeter were located at the time I purchased the boat.
The backside of depth sounder and the knotmeter were on the starboard side of the galley. Also on this side, as you can see in the picture below, was the VHF radio.
I would later install a battery charger on this side of the galley, underneath the cabin trunk inset. Below, we see the protective shield made of Spanish cedar and mahogany, which I constructed to cover the battery charger when not in use.
I placed hinges on this shield so that the charger could have as much ventilation as possible when necessary. For more on this project, see my article, "Electrical, Battery Charger."
If you read the first part of the present article on the GPS and VHF, where I discussed my views on traditional navigation, then you'll know that, to me, a traditional compass is paramount on a cruising sailboat, even in this age of high-tech, electronic devices. Knowing that I would definitely install a new compass on this boat, and knowing that I would install, for the first time on this boat, a GPS (one that would be integrated with a new VHF radio with DSC capability), I had to decide where to locate these devices. Would I keep the compass on the port side? Would I put the GPS where the old depth sounder and knotmeter were located? These were the questions I pondered long and hard as I tried to bring as much forethought as possible to this issue.

I briefly considered putting the compass on the bridge deck, i.e., the fiberglass bulkhead of sorts at the foot of the companionway. I had seen other boat owners install their compasses in this area.
One important thing, however, that I had to take into consideration was the air conditioner box that I had built for the companionway. I didn't plan to use this all the time. Nevertheless, there was no way I could use it at all with the compass situated in the bridge deck. Therefore, my choice was either the port or starboard side of cabin trunk.
In the end, I decided upon the port side . . . but not without careful consideration. Why the port side? Well, it was not because of the existing circular hole. I actually had to cut a new hole for this new compass. There was one big reason for locating the compass on this side - I did not want the GPS and the VHF to be directly above the stove.
As you can see from the picture below, the vapors from the pots on the stove surely would not have been good for the GPS and VHF. Some might wonder why these vapors would be of concern to me at all, since I had been foolish enough in the first place to locate so many other electrical devices in this part of the galley. My answer to that supposition is that my placement of these other electrical devices in this area was not made without careful deliberation. For more I my decision making process, see my numerous articles under the heading "Electrical." I will say here in my defense, though, that I would eventually install a removable, snap-in-place, fireproof cloth in the area around the stove as a protective barrier against oils and vapors while cooking. Yes, I could protect the panels and switches that were adjacent to the stove with a cloth such as this one, but I could not protect electronic equipment that was directly above it. For more on my installation of the compass, see my article by that title.
Having decided to install the GPS on the starboard side of the cabin trunk, I now needed to decide whether to flush-mount it on the face of the cabin trunk itself, or to mount it on what is commonly called a "swing-arm," a device, located on the interior, which allows the helmsman to swing the GPS outward when necessary, so that it will be visible to him in the cockpit.
Curious about the swing-arm approach to mounting a GPS, I did a little research on the Internet, and I found a number of examples of different sailboat owners using these on their vessels. Especially helpful were the several pictures that I have included below. I should note first that I did this research some time ago, before I ever started writing articles on this website. Accordingly, I collected these images quickly for my own research purposes. If the sailboat owner who took these images would like for me to cite him, or if he would like me to remove them from this article, I will be happy to do so. I include them here simply for illustrative purposes.
As you can see from the picture above and below, this sailboat owner constructed his own swing-arm. He used a wing-nut at the joint to secure the arm in the desired position.
The benefit of his homemade swing-arm, just like those rather expensive store-bought ones that are made of aluminum, is that it can be swung inward when not in use. This is good for several reasons. First, it allows the GPS to be protected from the elements. Likewise, it allows it to be protected from theft. Additionally, it allows the mariner to consult the GPS will sitting in the main salon, when at anchor.
The store-bought, aluminum ones, also have their benefits, the most important of which is that some of them allow for the mounting not only of the GPS, but also the VHF. An acquaintance of mine in Charleston, South Carolina owns a Catalina 27. He installed the swing arm, that you see pictured below, on his boat. I can say that it sure is handy having both of these electronic devices right next to each other and easily visible in the cockpit. I can also say, however, that this swing-arm can sometimes be a pain. For one thing, it partially obstructs the companionway. This means that every time someone goes below, he either has to work his way around it, or he has to swing it out of the way. The other thing is that the arm does not stay fixed in one position when the boat is in choppy water. Instead, it slowly inches its way back down into the boat.
Taking the above issues into consideration, I decided that the best thing to do for my boat, with my layout, was to forget about the swing-arm and instead mount the GPS on the face of the cabin trunk. For one thing, a swing-arm would have blocked access to a companionway already partially blocked by an air conditioner box. Secondly, there was the issue of weather, specifically bad weather. How do you close off the cabin with washboards (to prevent the ingress of water) and still use the GPS? This would be one of the times when you would want this electronic device to be handy, especially if the visibility was poor.
Having concluded that I would mount the GPS on the face of the cabin trunk, I next needed to figure out how I would cut the hole for it. Would I fill the old instrument holes with fiberglass, or would I disguise them with a panel of wood? These are just two of the questions I considered as I moved forward with this project.
This ends this second posting in my multi-part article on the installation of a new GPS and VHF in Oystercatcher, my Ericson 25.