| Term: | Ice keel |
| Definition: | From the point of view of the submariner, a downward-projecting ridge on the underside of the ice canopy-the counterpart of a ridge. Ice keels may extend as much as 165 ft (50 m) below sea level. |
| Term: | Ice keel |
| Definition: | From the point of view of the submariner, a downward-projecting ridge on the underside of the ice canopy; the counterpart of a ridge. Ice keels may extend as much as 50 m below sea level. |
| Term: | Ice keel |
| Definition: | The submerged counterpart of an ice ridge. |
| Term: | Ice keel |
| Definition: | From the point of view of the submariner, a downward-projecting ridge on the underside of the ice canopy; the counterpart of a ridge; ice keels may extend as much as 50 meters (55 yards) below sea level. |
| Term: | Ice keel |
| Definition: | Sea ice terminology which describes a downward-projecting ridge on the underside of the ice canopy; the submerged counterpart of a ridge. Ice keels may extend to as much as 50 metres below the surface. |