The use of buoys—in the form of casks or iron-banded wood staves—dates back to the time of the Norman invasion of England in 1066. From that time, development of the English buoy was slow. It was not until the reign of Henry VIII (1491-1547) that the importance of maritime trade to England and, in turn, the need for a means to direct ships through navigable waters was realized. By royal charter in 1514, Henry founded Trinity House, an organization that provided essential assistance in shipping for 450 years. By the mid-1500s, use of buoys had spread and most of the principal ports and harbors used them to mark channel entrances. Beginning in the 1600s, the first different colored and shaped buoys were used by the Germans along the Baltic coast. Each color and shape of these wooden buoys had a different meaning to the local sailors...