I'd like to draw your attention to a new book on the history for the use of blue on ships. This book, now in English, by Joachim Mullerschon is available through:   http://www.modellbau-muellerschoen.de/buch-en.htm   Titled The colour blue in historic shipbuilding, originally Die Farbe Blau im historischen Schiffbau - von der Antike bis zur Neuzeit, This book, lavishly illustrated in color, traces the use of different blue pigments from antiquity to the present as used on shi