Full Idea
The Ship of Theseus seems to be a case of 'asymmetric' fission (where one resultant entity has a stronger claim). Many see the continuously rebuilt ship as the stronger candidate, but each candidate, without the other, would be the original ship.
Gist of Idea
The ship undergoes 'asymmetric' fission, where one candidate is seen as stronger
Source
Theodore Sider (Four Dimensionalism [2001], 5.1)
Book Reference
Sider,Theodore: 'Four Dimensionalism' [OUP 2003], p.145