what is the historical origin of the rainbow symbol in the royal ark mariner degree

The rainbow symbol in the Royal Ark Mariner degree originates from the Biblical narrative of Noah, where it represents the covenant made by God following the Deluge, surrounding Noah and his family, as a paper read before Quatuor Coronati Lodge notes. The degree itself centers on the Biblical account of the building and voyage of Noah's Ark, the Flood, and the dove 1, as Mark Masons' Hall's website records.

By 1798, members of the degree assembled in bodies known as Royal Ark Vessels and wore a broad sash ribbon representing a rainbow alongside an apron embellished with an ark and dove 1.