Containerships are staying active into the final days of 2020 amid high cargo demand, port congestion and tight supply, according to a sector analysis.

The global inactive fleet stood at 147 ships carrying 600,173 teu, representing 2.5% of all boxships as of 21 December, Alphaliner's last weekly report for 2020 showed.

"Persistently strong cargo demand, a fairly high number of vessels waiting at anchorage to berth at congested ports and a general shortage of ships and box equipment combine to keep the global inactive containership fleet low — even as we near the end of the year," Alphaliner said.

"The inactive fleet continued its downward trend as it fell by 11 ships and 55,811 teu in comparison to the previous count."

Of those 147 vessels, 64 of them carrying 229,597 teu were idle ships, reflecting a 14-unit, 55,890-teu decline in capacity over the prior two weeks, according to the report.

Out of this idle fleet, Alphaliner found 33 ships under carrier control for a total of 178,174 teu, while the number of non-operating owner (NOO) controlled vessels came in at 31 units for 51,423 teu.

The number of ships in yards, which account for 62% of inactive fleet capacity, rose by three to 83 ships since the previous survey, while yard capacity remains flat at 371,661 teu.

The sector has only one idle NOO ship with a capacity above 5,100 teu, yet 30 NOO vessels in the below 5,100-teu, panamax category are at idle status, including 12 in lay-up or in limbo.

"The inactive fleet’s overall contraction was mainly related to a reduction of carrier-controlled idle tonnage, where — on average — idle vessels currently are also lot bigger in size than NOO-controlled idle ships."