Sailors Shannon Lenz and Tom Whitehead have recalled their encounter with a huge sea of floating pumice in the Pacific Ocean in early August.

They said the volcanic rocks stretched "to the horizon on all sides".

The "pumice raft", likely to have formed from an underwater eruption, spans over 150 sq km (93 sq miles) and is currently drifting westward through the Pacific Ocean, scientists say.

Read more: Giant volcanic rock 'raft' found in Pacific Ocean