: Cover a skin-on-frame boat with clear mylar. Don't know if it is possible; my
: Google searches came up empty... call it "The Invisible Boat"
: .

It is possible to do this with mylar, or for a lot less money you could do it with clear vinyl -- which stretches and could be seamed by heat or glue/solvents so it would make a nice taut skin.

The problem with viewing underwater though would be from glare and refraction, and a clear kayak doesn't solve this problem.

A "Fish scope" is little more than a dark box with a glass window on one end and an eyehole on the other. By excluding light from the upper surface of the glass you eliminate the glare and you can see under the water.

For a really good view, you would want to place the window in the bottom of the boat in such a place where you could keep the dry side as dark as possible.

At a minimum you would want to place the window as far forward from the cockpit as you could, and then paint the inside of the deck with a flat black paint. You might need to paint quite a large area to reduce the reflections enough so you can see through the window. To block the most light you would also want to make a very tight fit in your cockpit, or use a light-proof sprayskirt, and have an open, viewing "tube" with the inside darkened to a flat black mounted just in front of the cockpit. The viewing tube would be positioned so that it aimed at the window, and the paddler could lean forward and see through it.

Pulling an opaque poncho over your head would also do the trick, but it would be hot as anything in the summer, and you could not see where you were going.

A double kayak designed for underwater viewing would have a forward cockpit which could be SAFELY covered completely. (Perhaps with an opaque fabric) The passenger in the front position could then sit, or even lie down and view through the window while the paddler in the 2nd position propelled the craft. This would be a very nice camera setup, too, for videos.

Thinking of video: With the prices of video and digital cameras dropping you could make fairly small window in the hull -- say 2 inches in diameter -- and mount a video camera to this so that all reflections are eliminated. A monitor mounted by the coaming, or worn on the kayaker like eyeglasses would give them a superior image. There are now digital cameras under $100 with 1 megapixel resolution or less which have a LCD viewing screen. An experimenter with suitable funds to purchase one of these (perhaps used?) would find that a few minutes dismantling the camera would allow them to separate the viewing screen from the lens and image sensor. Mount half the camera by the viewing port, and attach it with whatever necessary wires to the screen, which would be closer to the kayaker. Rig a shutter release and you could bring back photos of what you observed. Bring extra batteries.

as for the windo itself? get a sheet of acrylic glazing material from the hardware store. This is what is commonly used for storm doors. The HomeDepot near me sells precut pieces in an 8x10 inch size (good for picture frames) for under $5. Larger pieces are priced higher, of course. This material is about 1/10th of an inch thick, so it will fit on a rabbet cut into the plywood or cedar strip hull. A good marine sealer or silicone or acrylic caulk should hold it in place, but you may want to add a metal flange around the edge, and secure that with rubber-gasketed bolts and nuts placed through the hull. The smaller you make the windows the better. Consider two or 4 smaller windows an inch or two apart rather than one larger one.

Just some thoughts.

PGJ