Sea Intelligence noted that one of the ripple effects of the pandemic has been a sharp increase in the number of extra vessels per week as it looked into how the physical number of vessels deployed on liner services was contributing in port congestion.

In a statement, the maritime analyst noted that simply put, it takes more time to handle two 5,000 TEU vessels than it does to handle one 10,000 TEU vessel in a congested environment, as a minimum due to the extra time going to and from berth.

It noted that the rise in extra vessels has manifested itself on the Transpacific already in 2020, and then also came to Asia-Europe in 2021 and has escalated very sharply in the 2021 peak season. 

Sea Intelligence said on Asia-North America West Coast, the 2012-2019 average number of extra vessels on the trade was 1.9 vessels per week, increasing to 5 in 2020 when the pandemic struck, with the 4-week average currently standing at 14 additional vessels — with 2020-2021 scenario showing "extreme developments."

It said the additional spike in 2021 driven by a combination of poor schedule reliability causing the sliding of vessel departures, as well as the insertion of a number of additional vessels.

"The development on the Asia-North America East Coast trade lane was similar, although the magnitude of the 2021 spike was a little smaller than seen on Asia to North America West Coast," the analyst said, adding that on Asia-North Europe, under normal circumstances, very few such extra vessels are deployed.

Sea Intelligence said the initial impact of the pandemic was also very small, starting to increase in 2021 and worsened due to the Suez Canal blockage.

The pattern seen on Asia-Mediterranean was not different from that on Asia-North Europe, it added, noting that with a limited impact of the pandemic in 2020, but a sharp increase in 2021 starting before the Suez Canal blockage.

"The consequence of this is that the ports have to handle a much larger number of vessels than they were used to before the pandemic, in turn worsening the bottleneck problems," it added.