The Law of Ships Article 20

In the event that a registered ship is lost or wasted, loses its R.O.C. nationality, has been missing for more than six months or sunk and unable to be salvaged or repaired, the owner of the ship shall apply for cancellation of the ship's ownership registration to the shipping administration authority of the ship's port of registry according to the Ship Registration Law within 4 months after discovery or occurrence of such facts. The original Certificate of Vessel's Nationality (Register) of such ship shall then be withdrawn, unless it has been lost.For any ship modified into yacht or small ship, the owner of the ship shall apply for registration and issuance of a license pursuant to relevant regulations within 3 months from the date of completion of modification. The original Certificate of Vessel's Nationality (Register) shall be withdrawn, unless it has been lost.