The distinguishing colours indicate that Officer's particular area of expertise. That's why Deck Officers don't have any.Purple cloth signifying engineers is often erroneously thought to be an award for the bravery of engineers on the Titanic. However even if so, why would it have been purple? Apart from being the colour that senators edged their togas with in ancient Rome, why purple? Whats so special about purple?, and if it is so special then the deck officers would have had it first.
Ouch! Who threw that???