Vessel bunching — which occurs when the number of sailings in a given week comes in excess of the number of weekly services — has surged to a level almost nearly comparable to what was observed during the peak of the COVID-19 pandemic.
Sea-Intelligence noted that from a network design perspective, one vessel would be scheduled to depart from an origin region each week for every deep-sea liner service. However, in the real world, a shipping line can have multiple vessels departing in the same week on the same service.
This can be caused by vessel delays, where a delayed vessel slides into the following week, vessel shortages, where shipping lines deploy two smaller vessels to replace a larger vessel, or because of extra-loader vessels to cater to excess demand/cargo backlog.
"We term this phenomenon as 'vessel bunching' ... so if there are 17 sailings in one week, and there are 15 weekly services, 'vessel bunching' equals 2," the Danish maritime data analytics firm said.
In a recent analysis, Sea-Intelligence noted that vessel bunching trends were identified by calculating an average observed over a rolling 10-week period, as illustrated in Figure 1 for Asia-North Europe.
[Source: Sea-Intelligence]
"In the 8 years prior to the pandemic, there was a relatively low level of vessel bunching, whereas the pandemic caused an extreme increase," said Alan Murphy, CEO of Sea-Intelligence.
"Towards the end of 2023, this had again almost normalised. However, the Red Sea crisis in 2024 has caused a new surge in vessel bunching, back to a level almost matching the pandemic peak," he added.
Murphy noted that higher vessel bunching creates a larger pressure on ports and terminals.
He said that while the offered capacity might be the same when seen over two weeks, i.e., no vessel sailing in one week followed by two vessels sailing in the following week, having two vessels depart in one week and zero vessels in the second week, "creates an extraordinarily high workload in one week and none in the second week."
"This clearly increases the risk of port congestion – and as a ripple effect, a similar crunch on the use of truck, rail, and barge capacity," the Sea-Intelligence chief added.
"Vessel bunching can, therefore, be seen as a proxy measure for the pressure on ports and the corresponding likelihood of congestion problems. As such, given the data, there is no indication that the pressure on ports is about to be alleviated," Murphy further said.