A midair effort by environmental activists to block a Shell Offshore icebreaker from leaving its Portland dry-dock ended after more than 38 hours, as Portland firefighters lowered Greenpeace protesters from the St. Johns Bridge and the ship Fennica slowly passed jeering crowds.

Law-enforcement boats and jet skis chased "kayaktivists" across the Willamette River as the Fennica passed unmolested through a channel Portland Fire & Rescue had cleared through the protesters dangling from the bridge.

Protesters have begun a party in Cathedral Park to clean up and celebrate the Greenpeace activists.

"This whole thing has felt like a victory," said Portland Rising Tide activist Meredith Cocks. "We've captured the attention of the country…Delaying them two days isn't a lot, but it could be 15 percent of their drilling season."

The U.S. Coast Guard coordinated firefighters, the Portland Police Bureau and the Oregon Department of Transportation in lowering three protesters from their positions under the bridge's span. The involvement of those agencies suggested both Gov. Kate Brown and Portland Mayor Charlie Hales signed off on the extraction.

The forced removal of protesters followed a failed attempt by the Shell icebreaker Fennica to leave its dry-dock this morning, and a ruling by a federal judge that Greenpeace must pay Shell $2,500 for each hour protesters block the ship's departure.

Here's video of the ship making its anticlimactic way to Alaska: