The median time spent by container vessels in port began to grow sharply in the second half of 2020, continuing into the first half of 2021, according to Sea-Intelligence, a provider of research and analysis within the global supply chain industry.

The Danish company used data published by the United Nations Conference on Trade and Development (UNCTAD) on port stays to see if it could shed light on the current bottleneck issues faced by the container shipping industry.

A quick calculation showed that the median time spent in port in the first six months of 2021 was higher by 11% compared to the pre-pandemic average time spent in port in 2018-2019, according to Sea-Intelligence's analysts.

Comparing this to the global demand data published by Container Trade Statistics (CTS) – which was up 5.5% over the same period – shows that the efficiency of the port calls themselves declined in 2021.

Compared to the other vessel types, the median time spent in port for container vessels recorded a far greater increase.

"Hence, to some degree, the container shipping sector is more impacted by the supply chain bottlenecks than other parts of shipping – which in all likelihood can be traced to the container shipping sector having a strong reliance on a land-side intermodal set up, which also suffers from severe bottlenecks presently," commented Alan Murphy, CEO of Sea-Intelligence.