Weatherproofing project with display for a boat

First off (before I forget!) Here is a link to my pictures, project files, etc...

I bought a 1970's boat for $300. I put a lot of work into it and it is finally getting to the point where it is nice. That is a whole different story you can read about here:

I am to the point where I want to start making the thing fancy. Earlier I had decided that it would cost about the same or less to use an Arduino with a cheap GPS receiver to report speed than to buy a new speed indicator (The old one was all busted up), and now I am expanding on that idea. I want my little speed reporting computer to also take care of everything else onboard the boat. I am buying a 128 x 64 LCD display and want to mount it into the dash behind the steering wheel.

In the Google Drive share I put at the top I have my project files, my eagle files, and picture etc... I plan on keeping it updated as I work on my little project, but before I get more side-tracked, the question I came here for: What is the best way to weatherproof this display? A boat is constantly exposed to moisture, and it is stored outdoors, so it has to endure the cold and the hot as well. I mainly stick to freshwater, but saltwater is not out of the question. I came up with an idea of how I might do it, but I had not found any examples of how other people have done something similar before. Here is what I was thinking: and here is the dash:

I was basically going to try cutting a window through the dash (it is basically a sheet of fiberglass on top of a sheet of wood) and leaving a bit of a lip to silicone a bit of plexiglass in place, and then screw the display in from the other side (the screen is from here: To keep water from leaching in I would put a thin layer of silicone on the exposed wood and finish it off with a plastic box of some sort attached to the back with connectors filled with dielectric grease. It might be better to have everything in one container that slides into a hole, but I am not sure where to get/how to make something like that. Anybody here have any experience with this kind of thing?

Google "ip67 enclosure with transparent lid" and select Images. You might see something that you could work into your design. At least you'd be assured of a truly waterproof enclosure.

Thank you, I will give those a look.