Springing as a nautical term refers to global (vertical) resonant hull girder vibrations induced by continuous wave loading.
[1] Whipping is a transient phenomenon of the same hull girder vibrations due to excessive impulsive loading in the bow or stern of the vessel.
Springing induced vibrations can already be present in low or moderate sea states when resonant conditions occur between wave lengths present in the wave spectrum and the hull girder natural modes, while whipping typically requires rough sea states before the very local occurring slamming impact has sufficient energy to excite the global structural vibration modes.
The Great Lake bulk carriers are typically rather blunt and slender ships (length to width ratio of 10) sailing at shallow draft resulting in long natural periods of about 2 seconds.
In the extreme cases springing may cause severe fatigue cracking of critical structural details, especially in moderate to rough head seas with low peak periods.