It's considered bad juju to rename a ship.
When a ship is given a name it is registered in the Ledger of the Deep. If one changes the ship's name, Poseidon will see this as an attempt to slip one by, and misfortune soon follows. Never rename a ship.
I'm not a superstitious man by nature, but I do stick to this. For example in Elite Dangerous if I want change a ship's name I will sell this one and buy an identical one, taking a bit of a hit in the wallet. But far be it for me to tempt fate!
