The four main-battery turrets were arranged across three levels rather than two. A and X formed the middle pair, while B and Y sat at different heights. The common level of A and X most likely made them the reference pair for gunlaying. The arrangement was workable and not unusual, though a two-level battery would have been simpler.
Notable Point · 19:46-20:41
Three gun levels and the sighting reference
Duquesne's A and X turrets shared the middle level, while B and Y stood at different heights, putting the four main turrets on three levels.