Meanings of new pontoon in English

A new pontoon has recently appeared off the wall, moored in the River Liffey.

A new pontoon has recently appeared off the wall(...)

Deep in its gorge below our feet flowed the Tugela, with the new pontoon bridge visible to the left, just below a fine waterfall.

Nothing else was done during the day, but at nightfall Lyttelton's Brigade was relieved by Hildyard's, which marched across the new pontoon (No.