From Blaseball Wiki
Sinking Ship is a Team Modification, first seen after the Arcana Drawing in Season β13.
A team with Sinking Ship is improved by 1% for every player below 14 on their roster, and impaired by 1% for every player above 14 on their roster.
During the Season 13 Earlsiesta, the Hawai'i Fridays' card, II The High Priestess , was drawn as the first card of the season's reading. The Fridays were immediately granted Sinking Ship as a Permanent modification.