 inside , 2⅜ ins (c 60 mm) in extreme depth and 6ins (c 150 mm).in extreme length, extending inwards and downwards ...but not within 1 ½ ins of the outer face of the joint flange.The total capacity of the hole, measured by filling it with water, was 15 ½ cubic inches (about 250 ml) and, as the metal immediately round the hole was not sound, this amount does not measure the actual extent of the flaw.