Lot of issues. Different countries , airports and ports have different vacination/quarantine requirements. That keep changing from day to day. Imagine most of y

Lot of issues. Different countries , airports and ports have different vacination/quarantine requirements. That keep changing from day to day. Imagine most of your ships, planes, pilots or seafarers getting sick or stuck in quarantine somewhere or the other for almost a year now. Things get better as govts wake up to such non uniform policies. In the mean time expect all kinds random break downs.