This problem was addressed and
solved years ago in the motion picture production business by the guys at
Hoodman Corporation, but you don't need to buy one of their overpriced products to solve your problem.
If you go to their web page and have a look at what they have
for sale under "Field
Monitor," you'll quickly gain an understanding of how the Hoodman products
work. Most people make the mistake of putting something
above the screen, in the mistaken assumption that it is sunlight falling on the screen that is
washing out the image. But if the sun is
not falling directly on the screen, then sunlight is not the problem.
The real problem is that the screen is reflecting what is in front of it back into the viewer's eyes. Most of the time, that is the viewer, himself. It's
funny to watch people stare at a screen outdoors, trying to "shade" it with their hand, and completely unable to see the image. That's
funny to me, because they can't train their eye to look at what they're actually seeing on the screen, and instead stare helplessly at the screen, looking for the output of the device that they just can't see.
Once you learn to see what is there, you will quickly note that it's you and whatever is behind you that you're actually seeing reflected. The solution, therefore, is to place a flat black card
under the screen and tilted up so that the screen reflects the flat black surface. Since the angle of reflection is equal to the angle of incidence, you want to look slightly downward at the screen rather than straight on, so that the black card is reflected back to your eye.
Voila! The output of the screen is now visible!
The two sides and the top of the "hood" that you can make out of show card (thin card stock that is flat black on one side, white on the other) serve only one purpose - to keep the sun, or any other light source, off of the bottom piece of flat black card.
You can see by looking at the Hoodman products that the principle is always the same: tilt the screen of the output device downward, and the flat black card below the screen upward. Then attach two sides and a top piece to keep any ambient light off the lower card.
The
hood can be attached to the device by tape, but if you prefer something that looks a little more professional, you can attach it with velcro. The hook piece goes on the device, and the loop piece goes on the
hood.
There ya go - problem solved! Spend that $1500 on something nice for your vessel, or for yourself.
TaoJones