Why sailors can regard renaming a ship as dangerous

Why is it considered rude or unlucky to rename a ship?

The original name is bound up with the ship's blessing and perceived personality, so changing it is treated as disturbing that identity and its luck.

The objection comes from maritime custom rather than a technical rule. A ship receives a name and a blessing, and sailors often speak of the vessel as having a distinct personality. Changing the name can look like tampering with that original identity and good fortune. The belief persists as a religious or superstitious strand of naval culture even among people who would not state it as formal doctrine.