To assist navigation and act as a warning in waters that are normally populated with icebergs, sailors use six ice classifications for identification. Iceberg height is also important to its classification, but shown here are only the specific classifications' lengths (the portion of the iceberg that we can clearly see): Very Large are over 670 feet in length, Large from 401 to 670 feet, Medium 201 to 400 feet, Small 47 to 200 feet, Bergy Bits 15 to 46 feet and Growlers under 15 feet.