Defence scientists developed SeaMark, a marine dye marker, as a safe, effective and longer-lasting alternative to flares and smoke signals for search and rescue (SAR) at sea.
When scattered around a person or craft, its dye flakes instantly to release an intensely coloured fluorescent dye onto the surface of the water.
Unlike conventional dyes, the SeaMark flakes dissolve slowly, releasing further dye at a rate determined by the solubility of the gums used to bind it. One hundred grams of SeaMark dye can cover an area approximately 100 metres long and it is visible from a distance of up to 10 kilometres for far longer than conventional markers used in SAR.
Defence scientists amalgamated conventional fluorescent dyes with buoyant polymer microspheres by means of selectively soluble binder gums, and then pressed, dried flaked, and packaged the mixture in a water resistant container.
The dye marker is environmentally safe, not injurious to human health and can be stored for several years. The marine dye lasts for more than one hour in moderate seas, far longer than conventional dyes.
Seamark was licensed to the Melbourne-based company Pains Wessex Australia Pty Ltd in 1992 to develop, manufacture and market the Seamark technology. It is now sold in several countries including France, Hong Kong, Ireland, the Netherlands, New Zealand, Singapore, South Africa and the United Kingdom.