From BoatSafe.com (and a lot of other sources too)....
Renaming a boat is, of course, not something to be done lightly. Since the beginning of time, sailors have sworn that there are unlucky ships and the unluckiest ships of all are those who have defied the gods and changed their names. So, is there a way to change a name and not incur the wrath of those deities that rule the elements? Yes, Virginia, there is.
According to legend, each and every vessel is recorded by name in the Ledger of the Deep and is known personally to Poseidon, or Neptune, the god of the sea. It is logical therefore, if we wish to change the name of our boat, the first thing we must do is to purge its name from the Ledger of the Deep and from Poseidonís memory.
This is an involved process beginning with the removal or obliteration of every trace of the boatís current identity. This is essential and must be done thoroughly.
I once went through the ceremony after the owner had assured me that every reference to his boatís old name had been purged from her. A couple of weeks later, he discovered he had missed a faded name on her floating key chain. I advised him to start over, perhaps with a little extra libation for the ruler of the sea. Unfortunately, he declined.
Since then, his boat has been struck by lightning, had its engine ruined by the ingress of the sea, been damaged by collision and finally sunk! It pays to be thorough.
In purging your boat, it is acceptable to use White-Out or some similar obliterating fluid to expunge the boatís name from log books, engine and maintenance records etc., but it is much easier to simply remove the offending document from the boat and start afresh. Donít forget the life rings and especially the transom and forward name boards.
Do not under any circumstances carry aboard any item bearing your boatís new name until the purging and renaming ceremonies have been completed!
Once you are certain every reference to her old name has been removed from her, all that is left to do is to prepare a metal tag with the old name written on it in water-soluble ink. You will also need a bottle of reasonably good Champagne. Plain old sparkling wine wonít cut it. Since this is an auspicious occasion, it is a good time to invite your friends to witness and to party. Begin by invoking the name of the ruler of the deep as follows:
Oh mighty and great ruler of the seas and oceans, to whom all ships and we who venture upon your vast domain are required to pay homage, implore you in your graciousness to expunge for all time from your records and recollection the name (here insert the old name of your vessel) which has ceased to be an entity in your kingdom. As proof thereof, we submit this ingot bearing her name to be corrupted through your powers and forever be purged from the sea.
(At this point, the prepared metal tag is dropped from the bow of the boat into the sea.)
In grateful acknowledgment of your munificence and dispensation, we offer these libations to your majesty and your court.
(Pour at least half of the bottle of Champagne into the sea from East to West. The remainder may be passed among your guests.)
It is usual for the renaming ceremony to be conducted immediately following the purging ceremony, although it may be done at any time after the purging ceremony. For this portion of the proceedings, you will need more Champagne, Much more because you have a few more gods to appease.Begin the renaming by again calling Poseidon as follows:
Oh mighty and great ruler of the seas and oceans, to whom all ships and we who venture upon your vast domain are required to pay homage, implore you in your graciousness to take unto your records and recollection this worthy vessel hereafter and for all time known as (Here insert the new name you have chosen), guarding her with your mighty arm and trident and ensuring her of safe and rapid passage throughout her journeys within your realm. In appreciation of your munificence, dispensation and in honor of your greatness, we offer these libations to your majesty and your court.
(At this point, one bottle of Champagne, less one glass for the master and one glass for the mate are poured into the sea from West to East.)
The next step in the renaming ceremony is to appease the gods of the winds. This will assure you of fair winds and smooth seas. Because the four winds are brothers, it is permissible to invoke them all at the same time, however, during the ceremony; you must address each by name. Begin in this manner:
Oh mighty rulers of the winds, through whose power our frail vessels traverse the wild and faceless deep, we implore you to grant this worthy vessel (Insert your boatís new name) the benefits and pleasures of your bounty, ensuring us of your gentle ministration according to our needs.
(Facing north, pour a generous libation of Champagne into a Champagne flute and fling to the North as you intone Great Boreas, exalted ruler of the North Wind, grant us permission to use your mighty powers in the pursuit of our lawful endeavors, ever sparing us the overwhelming scourge of your frigid breath.
(Facing west, pour the same amount of Champagne and fling to the West while intoning Great Zephyrus, exalted ruler of the West Wind, grant us permission to use your mighty powers in the pursuit of our lawful endeavors, ever sparing us the overwhelming scourge of your wild breath.
(Facing east, repeat and fling to the East.) Great Eurus, exalted ruler of the East Wind, grant us permission to use your mighty powers in the pursuit of our lawful endeavors, ever sparing us the overwhelming scourge of your mighty breath.
(Facing south, repeat, flinging to the South.) Great Notus, exalted ruler of the South Wind, grant us permission to use your mighty powers in the pursuit of our lawful endeavors, ever sparing us the overwhelming scourge of your scalding breath.
Of course, any champagne remaining will be the beginnings of a suitable celebration in honor of the occasion.
Once the ceremony has been completed, you may bring aboard any and all items bearing the new name of your vessel. If you must schedule the painting of the new name on the transom before the ceremony, be sure the name is not revealed before the ceremony is finished. It may be covered with bunting or some other suitable material.