G'day, I had a shoulder reco due to multiple dislocations when I was 20. (I'm now 31). The surgery was well worth while as it hasnt popped out since, but it does get tired quicker than it used to, or maybe it's because I'm older now?
Recovery for me was about 3 months before I could flatwater sail, and ocean sailing was about 6.
I started aqua therapy straight away with light movements for about 2 weeks and then doggie paddling followed by breast stroke. (mmmm stroking breasts!)
I reckon I had 95% strength by 1 year but It's never going to be 100% again. Once your joints are buggered there buggered for life.