There are almost no container ships in the world left for liners to charter. Secondhand purchase prices are through the roof. It takes two years or more to get a newly built ship. How can liners find more capacity?

There is a way — without adding ships — for liners to move more cargo and take even greater advantage of today’s stratospheric rates: speed up.

That’s exactly what they’re doing, according to new data from VesselsValue and MarineTraffic. Container ships are moving faster despite the fact that fuel consumption, and thus marine bunker fuel costs, rise exponentially with speed. Carbon emissions also surge, a politically sensitive side effect.

Carriers are stepping on the gas despite spending the last decade focused on the opposite strategy, “slow steaming,” and despite container ships built in recent years being specifically designed for slower speeds.

Just one of many examples of container ships recently sailing westbound at 20 knots or more: Automatic Identification System (AIS) vessel-position system data from MarineTraffic shows that the 4,253-twenty-foot equivalent unit (TEU) Seaspan Melbourne hit nearly 24 knots this month in the eastern Pacific on the backhaul from Los Angeles to China.

“Under normal circumstances, carriers would never do this, because bunker consumption is such a major cost factor,” said Simon Sundboell, CEO of shipping data provider eeSea. “But if you’re talking about rates of $12,000 [per forty-foot equivalent unit], you will do it.

“This is such a weird world we’re in,” he told American Shipper. “Because of freight rates, so many things are now possible.”

The caveat is that higher speeds may allow carriers to claw back some of the capacity they lost to port congestion, but there are limitations to how far this can go, so it won’t be a game-changer for cargo shippers.