Saturday, May 21, 2011

Blivet: 6" of chart plotter in a 4" space

This was a true greenfield project. This is Mike and Sandy's McAdaragh's shiny new Cruisers 415 MY. Mike wants a Garmin 7215 to go into the left panel, and there isn't quite enough space either in depth, or width to make it fit, or is there?  

We had a left side panel location that was both not quite wide enough, and on the right side not quite deep enough, so what's a body to do? The answer is the Garmin 7215 unit has to be lifted two inches, and some accommodation made for the small amount of extra width we need. Departing from the usual sequence of events, we will jump to show you the solution first, and then we will use Mister Peabody's "Wayback" machine to show you how it was done.

With Mister Peabody's Wayback machine we zap back to a week earlier. This is a lot like the sausage metaphor, you don't always want to see it being made. The first problem was that the Garmin 7215 was just a little too wide, and its sides would end up resting on the raised edges of the black dash foam surround leaving a 1/4" gap at the top and bottom. The second problem was, as you can see in the picture below is we have only 4" of depth at the lower right hand corner of the cutout, and we need 6". The companion way door, and screen are behind the panel.

There were two steps involved to make this work. First a back acrylic panel had to be made that would rest on the raised edges of the dash foam panel surround, and this had to look factory made all by itself. A template is constructed, and a couple of day later a new flat panel is trial fitted, and looks great. A good template is worth a thousand words, or ten thousand words of mine anyway.

Next came the tricky part. The unit has to be lifted two additional inches to clear the doors underneath, so a box has to be made to elavate it. The simple answer was to just build a square acrylic box (the Starboard beaver cut approach) and attach it to the new panel, and you're done. I didn't like the idea for two reasons. Since the unit was right next to the companion way, I wanted as few hard sharp edges as possible. The whole dash was also smooth and curvaceous, and I didn't think that a hard edged square black cube rising out of the panel would look like it really belonged. 

The design compromise was to make the sides of the structure curved softening the appearance of the structure. The catch with this is that when acrylic panels are heat bent, you lose about 3/16" of flat surface where it does the bend. This made the actual raised surface slightly larger than the panel it was going to mount to. The solution to the problem was to make the bends go slightly pass ninety degrees, leaving 1/8" side reveals at the edge of the panel it was mounted to.

It was almost perfect, but we are dealing with a boat. After fabrication we had what I call the short table leg problem. The foam dash surround was not perfectly flat where the new structure met it. There was a just a bit of a gap, and you could do a small rocking motion with the structure pivoting on the corners. This required the structure to be slightly compressed into the foam surround to get a good fit. Acrylics when solvent bonded create a joint almost as strong as the original material, but to show an abundance of caution, Bob from Delcraft  cut me some acrylic cleat blocks, and gave me a bottle of solvent. These were glued in around the interior edges just to make me sleep a little better.

In the end, "tres bon", it looked great. You can't see any fasteners, good fit, and looks like it came from the factory that way. This was the other boat I was working on while the "Grey Goose" project was ongoing. The other toys installed on this vessel were a Garmin 5212, 300 VHF AIS, Uniden redundant VHF below with a second station at the console, GXM51 weather receiver Garmin auto pilot, 4kw open array, and VGA video/audio feeds to the TV's.

The VGA TV feeds were the Xmas miracle of the project. Since the boat was under construction, I spec'ed the cables, Mike purchased and shipped them to Cruisers, and they installed them, and other video and audio cables during construction. I think this saved at least two days of cable pulling after the fact. You know you can buy a house with structured wiring, so why can't you buy a boat with it?

Mike and Sandy are currently lazing about in the Bahamas with Don Payzant's Nordhavn "Grey Goose" and others from the Sarasota Yacht Club. The only wart Mike has, is that the Garmin amplified VHF speaker isn't, but there is lots of redundancy, and I will have a new one ready to install when they wander back. Have lots of fun kids, and thanks for your patience Mike and Sandy.  Bill

I borrowed Misters Peabody's Wayback machine (WABAC) for the story. These interesting takes on history were part of Jay Ward's Bullwinkle cartoons, and were classic Feghoot's.

Schooner or later all sailors engage in rudder nonsense.


  1. Very cool. Who says you can't create something from nothing? I imagine stretching time and space is a qualifying skill to be marine installer? lol

  2. Thanks Robert, it is a TARDIS effect. The best Dr is the one you first saw, Mine is the fourth, Tom Baker. It was very fiddly, but turned out well.


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