Hi,
Has anyone installed a Plexiglas window in the bottom of their canoe. As you can imagine, I am a little hesitant to cut a hole in my boat… 
I would like to see below the surface so that I can search for driftwood. I am worried about the longevity of such a modification. I dont really have a problem with resealing it every 4-5 years. I also paddle in the winter, which worries me as the cold will contract and possibly cause leaks… I have an Old Town Discovery 119 with Poly 3.
instead of putting a hole in your canoe
Try looking into an underwater camera. They aren’t that expensive compared to destroying the valve of your canoe by trying to add a window to it. The cameras are easy to move so you can use it in any boat.
http://www.basspro.com/webapp/wcs/stores/servlet/Navigation?storeId=10151&catalogId=10051&langId=-1&searchTerm=underwater+cameras
maybe you should get
one of these instead:
http://www.oceankayak.com/kayaks/tandem_kayaks/peekaboo/
the window is even replaceable in case it ever breaks.
Easiest method:
Take a five gallon poly bucket.
Cut a circular hole in the bottom, and then glue a piece of plexiglass over it.
You hold it over the side just a tad underwater.
It works like a charm
It is great for wading around using it too
jack L
yeah that is and old trick
My Dad used one back in the late 40s only it was a glass bottom bucket.
Yes, make a viewer
Do as others have suggested and make a viewer for looking over the side. It would be a difficult project to install a window on the bottom of a canoe, and on a poly boat you might have to make it clamp all around the perimeter (nuts and bolts, gaskets, framework). It would ruin the lines of the boat, as far as how it moves through the water, partly due to the necessary flattening of the bottom of the hull. Finally, hardly anyone is able to avoid scratching the bottom of their boat. Plexiglass scratches terribly easily and probably would quickly become difficult to see through.