A traditional piece of diving headgear given a fresh lease on life after becoming popularised as a diving fashion statement by Jacques Cousteau, the red woollen beanie’s association with diving dates back to the early days of standard dress diving when its use had several very practical purposes.
Apart from wool’s naturally occurring properties as an insulating medium, “A red knitted cap is traditionally associated with the diver’s garments. Some form of cap is desirable, especially when the diver has to do long stops on the shot rope with his head resting against the cold damp copper of the helmet. ….“. From, ‘Deep Diving and Submarine Operations’, by Robert H. Davis. 1935 edition.
Although it was also suggested that the knitted woolen cap kept the diver’s hair in place, preventing stray strands from falling over his eyes and obstructing his vision or lodging in the helmet’s outlet valve and, unable to vent excess air from the suit, threatening the diver’s ability to control his depth and ascent rate, the beanie itself posed similar problems for some divers. Nevertheless, it was an accepted piece of headgear.
And the reason for the colour, red? Taking rest breaks from lengthy underwater tasks, divers would often elect to remain fully dressed – with the exception of the helmet – rather than go through the whole un-dressing, and subsequent dressing, procedures. Seated on the open decks of construction barges or pontoons during these tea-and-tobacco breaks, and weighed down by the corselet, breast weights and heavy boots and unable to quickly move out of harm’s way, the beanie acted as a red-for-danger signal flag to warn crane and derrick operators of the diver’s presence.