Global shipping faces a slowdown, quite literally.

Big container lines are reducing sailing speeds to save fuel.

They’re also taking longer routes around Africa to avoid fees for using the Suez canal.

It’s partly to save costs as the industry faces its biggest downturn since the global financial crisis a decade ago.

But there’s a deeper reason too.

Cash-crunched retailers don’t want the stock the ships are bringing.

Sportswear brand Puma one to say it’s managing excess stock by stowing it on slow-moving ships.

Gap another to reduce or slow down shipments.

Shipping giant Maersk says it’s found warehouse space for struggling retail customers.

It says some clients have asked to leave freight on ships, circling the world.

In all, the volume of apparel arriving in the U.S. is down by almost a fifth on the year.

Luggage is down by more than a third.

That all leaves a headache for retailers like Walmart and Amazon, which still want rapid deliveries.

They’ve been left to fight for space on the few fast ships left.

Air freight isn’t an option, as a lack of flights means a lack of capacity and higher prices.

Now July is when retailers start to order for the holiday and winter seasons.

With global retail sales forecast to be sharply down, the container ships may not be getting any faster.