Protesters in Portland, Oregon, dropped kayaks in the water and dangled from St John's bridge on 29 July to protest against the scheduled launch of the Fennica, an icebreaker ship to be used by Royal Dutch Shell for Arctic oil exploration.
Thirteen climbers dangled from the bridge on Portland's north west side, many with signs reading "#ShellNo." They were joined by several more demonstrators at sea on kayaks.
Environmentalists say the drilling will put pristine wilderness at risk and accelerate global warming, through continued reliance on burning fossil fuels.
Hundreds of activists in kayaks and small boats conducted a similar protest on a Seattle bay in May, demonstrating against plans by Shell to resume Arctic oil exploration while two of its drilling rigs were in the city's port.
In Portland, about 150 kayakers in boats protested Fennica's presence.