I had my right hip replaced in December 2012 and like yourself was concerned about being able to continue sailing. I had a Birmingham hip resurfacing operation and I did a lot of physo during the first three months.
By March I felt confident enough was to antifoul my boat and I sailed her back upto our summer mooring (200 mls)with one crew. Since them my confidence in the hip has grow and I did a lot of single handed sailing over the summer including a very windy single handed return trip back to Cumbria at the end of October.
I am still a little careful and about what I do but apart from a small loss of movement in one direction the operation has been 100% successful .
I wish your wife well and hope the operation is successful
As an Orthopod I am delighted that so many forumnites have had such a good result from total hip replacement. However, can I sound a note of caution. Firstly, not all replacements are the same. The resurfacing/Birmingham hip replacement is very much more stable than the usual hip replacement. It is not suitable for everyone. If you have a Birmingham hip your risk of dislocation is very much reduced.
If you have a non-resurfacing hip replacement then - in spite of the all the stories of people doing all activities without restriction - the main risk is of dislocation. The risk diminishes with time but never goes. The risk of dislocation depends on some technical aspects of the operation -the way the hip was "approached". Also the bigger the head (ball) the less the risk of replacement. Lastly the patient can influence the risk of replacement. The more extreme the position of the hip the greater the risk of replacement. I do not do hip replacements now, but when I did, I advised my patients not to flex the hip beyond 90 degrees.
The less common complication is fracture of the femur at the level of the tip of the prosthesis. This is most likely to occur is you jump off the boat onto the pontoon and land awkwardly. So don't!
Now I only do upper limb operations, and so worry more about fingers in winches and ring avulsion injuries with falls
So, all the best, but be careful. A new hip is not the same as a new gearbox. It will never be as good as new - although it will be better than the one taken out. It cannot simply be replaced if it then fails. A revision hip is never as good as a primary hip replacement