It is always sensible to keep a good reserve of emergency food, water, fuel, and other essentials. If possible also keep a reasonable stock of useful though not vital goods such as liquor, tobacco, confectionery and non perishable consumer goods in general.

However in this particular case I suspect that ships are idling at sea because the goods that they carry are not much in demand. If fewer consumer goods are being sold, then retailers will delay replenishment and wholesale suppliers will be left with excess stock. Importers may then lack either the money, or the physical storage space to accept more imports.

With the present low shipping rates it may make economic sense for ships to wait at sea until either another buyer for the cargo can be found, or until the original buyer belatedly has the money or the warehouse space to take the goods.

Any disruption to world trade is concerning, but in this case I suspect over supply or a slow down in demand, rather than shortages.
Still a good idea to stock up though, just in case.