27. Sea-ice draft is the thickness of the part of the ice that is submerged under the sea. Comparison of sea-ice draft data acquired on submarine cruises between 1993 and 1997 with similar data acquired between 1958 and 1976 indicates that the mean ice draft at the end of the melt season has decreased by about 1.3 m in most of the deep water portion of the Arctic Ocean, from 3.1 m in 1958-1976 to 1.8 m in the 1990s. In summary: ice draft in the 1990s is over a meter thinner than two to four decades earlier. The main draft has decreased from over 3 meters to under 2 meters, and the volume is down by some 40%.