I do know of totally blind folks who have successfully deer hunted.  Obviously, a sighted person is along to guide the hunter and help target the weapon on the animal.  That being said I would think it more of a communication issue than anything.  I'm thinking that the visually impaired person would be very good at teaching us how to communicate effectively with him or her on what needs to be done wether that be hunting or paddling a canoe.
In the past I've hosted a wheelchair bound youth deer hunting on our property.  I built an enclosed, accessible shelter for this purpose. Her rifle was mounted on the wheelchair and she had to move the chair via toggle sticks to sight on the animal.  She then would depress two devices, one on each arm of the chair, to fire her
weapon. She did and continues to do this very well.  I wish I had one tenth the determination that she has.
For me personally it was more a matter of myself getting past some barriers in my thinking than of the challenged person getting past their physical barriers.

Hope this helps.......mike