indimi - my wife and I purchased a Catalina 30 last spring, and we renamed it in August. Had a ceremony with sailing club friends and family. It was a lot of fun. Did probably sacrifice 2 - 3 bottles of wine to the seas, and a couple bottles of champagne during the renaming part, but ya gotta do what you gotta do! I've attached a few articles about the process (the "Sailboat Renaming Ceremony" is the one we basically followed). You have to first "dename" the boat. Some notes:
1) For an ingot, I just used a piece of scrap aluminum and etched the previous boat name in it with an engraver.
2) One step is to place a silver dollar (as old as possible) under the keel. We didn't want to unstep the mast so I epoxied the silver dollar in the cabin, to the mast support post just below the deck. It looks nice there. Also - I used a 1990 silver dollar because that's the year the boat was made and the year we were married. Bought it at a coin store for about $25.
3) Since it was nearing the end of the season, kids were going off to college, etc., we forgot to sail the boat backwards a few boat lengths. It's on our list of first things to do this season.
4) I've also attached the note cards I made for my wife and I to use during the ceremony.
5) Make it an event and have a lot of fun with it. People at our sailing club commented that no one's done it before and more should - I think mainly for the fun of it, the gathering of members (social) and of course - the free libations we provided!!
Good luck to you and your wife!!