rawing for Design 32/1B specifically drawn for the battleship USS Iowa (BB-61) has not yet been found. However, Iowa may have used this drawing for Design 32/1B for the North Carolina class battleships dated March 1943, since Iowa was photographed in 32/1B in early 1944. The specified vertical colors were navy blue (5-N) and haze gray (5-H). Iowa's application of 1B is a very good match to this drawing.
This is the only Design 1B drawing yet found.
Original drawing source: Supplement to Ships-2 March 1943 Plate XXIV.