I recently visited HMS Illustrious whilst she was in Liverpool and I vaguely remember that the tie-downs were 'randomly' ordered. That doesn't make sense I know, in that there weren't all exactly 1.5m apart in every direction for example. But I reckoned that they were specifically arranged for aircraft type. If you look at the lower image of the Jungly, you'll see the tie-downs around the tail wheels stop aft of the last set, but are set inboard and outboard of the ones used. The upper ima