If you were worried about rot the thing to do was avoid anything made from cotton. It's natural fiber and Mother Nature has provided microbes that will eat it if they can.
Sooner or later cracks will occure in the finish and that is where bugs will gain entrance. The bugs need air and moisture to survive so keeping the fabric dry will kill off those that try to eat your boat.
In general, cotton canvas will not last as long as man-made fibers so don't expect any miracles. To illustrate what you are up against consider the old timers who built wood and canvas canoes. They spent long hours rubbing white lead compond into the canvas before it was painted. The white lead compound concealed the weave and made for a smoothe finish but it's greatest benenfit was it was a powerful poison to anything that ingested it.

: Myself and a couple of friends have just finished two sof covered in #10
: cotton duck and have read that they could be painted w/ acrilic latex or
: oil base paint,do you need to prime? would oil be better because of the
: linseed in oil to feed the canvas to help protect from rot? does one seem
: better than the other? any feedback would be helpful thank you all. PS. I
: did check the archive for info.