The cup has since been competed for annually save for the years affected by the two World Wars and the COVID-19 pandemic. The eligibility rules have varied over the years, but the premise that the cup has always been open to all established crews has remained at its core.
The competition for the cup takes place every year, except during times of war (World Wars) and pandemics (COVID-19).  While the eligibility rules have shifted throughout history, the core idea that any established team can participate in the cup has always been upheld.