I have found netting that works well for all of that. It is usually green, made of nylon twine and is about 1.25 inch mesh (1/2 inch squares) and the best place I have bought it was in a gardening supply store. They sell it for stopping birds from eating fruit.
You can cut it to any length you need and I expect you can figure out how to rig it up.
Especially since anything you buy already made up likely won't fit your boat anyhow.
Here is a link explaining what I mean.
http://www.leevalley.com/garden/page.aspx?c=2&cat=2,51555&p=10444
You might be able to find something like it in your area from a garden supply, but since it is fish net you might have better luck with some place that sells to the commercial fishermen.
_________________________
May set off to explore without any sense of direction or how to return.