What was the last mostly wooden frontline warship?
Short answerThe Italian and Austrian fleets at Lissa are the suggested starting point. Later wooden small craft qualify only under a broader definition of frontline service.
NotesIdentifying the last vessel depends on what qualifies as a frontline warship. Italian and Austrian ships fighting at Lissa are the suggested candidates for the last mostly wooden vessels in that role. Wooden motor torpedo boats, small coastal minesweepers, and converted fishing vessels continued in military service much later. Whether their duties satisfy the question produces disagreement. Larger minesweepers and escorts such as the Halcyon and Algerine classes are distinguished as steel ships.