At the start of the twentieth century the Submarine Signal Company of Boston developed a system of electric bells that could be installed below water in lightships or, potentially, buoys. These could transmit underwater signals. Using a receiver an operator could determine the range and direction of the signal.
Full 1890 paper in Nature.
Once we’ve realised that Port is on the left only when facing the pointy end (not Italians – see later) we take these terms for granted. However, those of a curious bent might wonder how they came about . About ninety percent of us are right handed. Since roman times , at least, we have …
Navigation buoys have existed for centuries but, by the nineteenth century, differing systems caused confusion and prompted attempts to develop a common scheme. Growing trade, steamships, ship and buoy lighting technology increased the complexity of the problem which was not resolved, due to politics and war, until the late twentieth century.