Not exactly sure when it was adopted for private vessels and pleasure boats, but The SOLAS convention of 1914 addressed standardization of distress
rockets and other pyrotechnic distress
signals to avoid confusion such as arose with the Titanic disaster and the mistaken impression by Captain
Lord of the Californian that the rockets spotted by his deck
watch were nothing more than company signals. Prior to the invention of wireless telegraphy rockets and the newly invented Very Pistol were common in the last quarter of the 19th century.