The phrase "churning sea" refers to a rough and turbulent ocean or large body of water that is in a state of constant agitation and movement. Full definition
Exhausted by having to part churning seas of art advisers and would - be collectors without a sign from God, I departed for the civilized environs of the Marian Goodman Gallery, which was screening three films by Tacita Dean — one is a recent portrait of David Hockney — and showing chalk paintings and photographs of California clouds installed, appropriately, near the ceiling. (artforum.com)
Oil rigs are usually evacuated during major storms, and the devices used to stabilize cruise ships in churning seas can usually tame no more than moderate swells. (discovermagazine.com)
Also known as tropical cyclones and typhoons, these fierce storms can churn the seas into a violent topography of 50 - foot (15 - meter) peaks and valleys, redefine coastlines and reduce whole cities to watery ruin. (science.howstuffworks.com)