It All Depends !!
Depending upon your skills and confidence levels, virtually any craft can be used in "open" waters. Think about it, many adventurers have crossed the ocean in various things from kayaks, rowboats, small sailing dingies, etc.Now granted, going out to sea in a small boat is certainly not the ideal or even intelligent thing to try, but it has been done. Sometimes with success, sometimes with tragedy.However, if you use sound judgement as to when and how far out you choose to take your C-22, I dare say you could do it safely, assuming weather and sea conditions are not to drastic.But, bear in mind, ocean sailing is not what the C-22 was designed for, so you're really testing the limits by doing so. If you're really into open-water sailing, then maybe you need a different/bigger boat.