Which wood to use?

[Perplexed]

Oh well. If you really must follow advice - you'd better follow mine!

Hee Hee Hee! So modest....but good!

 

[Daydream believer]

Why put it in the bulkheads. Sometimes these instruments only last 5 minutes & one ends up with a great hole in the bulkhead. Furthermore if you have a crew you can bet that they will always be leaning against it so you cannot see it.
I do not like swing arm stuff & on my boat it would be out of range of the helmsman & also difficult to see if the eyes are not perfect. Especially if tired.
I have AIS on my plotter & crossing the Dover Strait as often as I do I need to be able to use that facility regularly. That means instant access to the plotter.
So my plotter is where I can use it, along with the autopilot control. Behind the helm where it is out of the way but still easy to use. I can swivel it 30 degrees either way to make it easier to see when sitting out.
I have made a polycarbonate hood for bad weather or if in port & cannot be bothered to remove it for the night.

If you still want to have the unit elsewhere you will see that my autopilot control is mounted in the lid of a waterproof box. The connections are all inside & the lid is held in place with 4 screws. You could get a box with a lid of suitable size. Have a single hole in it for the wire out the back. Screw the box to the bulkhead & mount the chartplotter in the lid
Then instead of unscrewing the chart plotter for any maintenance you unscrew the lid & the plotter comes away with all the connections folded up inside the box.. My picture show several wires because my box also houses the chart plotter chock box connections & power supply etc. When opened up there is plenty of slack for maintenance

 

[penberth3]

Personally I would use layers of exterior ply to get the correct thickness, then cut the aperture. Then sand smooth and cover with epoxy resin and cloth, then fill and fair and paint with two-pack. Lightly sand to remove any brush marks then compound and polish. Time consuming but you will have a professional finish that will last for years.

Building a solid block 170 mm thick would be heavy and a massive waste of material. A simple plywood box would do the same job.

 

[Daydream believer]

Building a solid block 170 mm thick would be heavy and a massive waste of material. A simple plywood box would do the same job.

Exposed edges are liable for delamination if not sealed sufficiently well

 

[AntarcticPilot]

Building a solid block 170 mm thick would be heavy and a massive waste of material. A simple plywood box would do the same job.

A hardwood frame with an inset plywood panel on the front would work well, and the edges of the plywood would be protected by the rebate.

 

[dansaskip]

I am another that used (on a previous boat) to have an instrument on a swinging arm. One of it's advantages is that when swung inside it was out of the way and you could "programme" it from inside the cabin, it was also protected from th elements when not in use. Boat was - Sadler 25

 

[PCUK]

Building a solid block 170 mm thick would be heavy and a massive waste of material. A simple plywood box would do the same job.

It would only be a frame once the aperture was cut! As for waste, ply is relatively cheap. I was looking for the easiest way to do it with few woodworking skills!