Grimm's Saga 281: The Phantom Ship
People who live on the Baltic Sea believe they can often foresee a shipwreck or stranding because the ship appears as a phantom several days or weeks before it sinks, at the very spot of its future demise. In the dark of night all parts of the ship, hull, rigging, mast and sail appear enveloped in fire. This they call wafeln. Men who will drown wafle as do houses that will burn and cities that will fall . On Sundays you can often hear the bells of sunken cities ringing, as they lie beneath the waves.
Wafeln probably comes from the Anglo-Saxon word wafian or the Old Norse vafra. It means to move unsteadily or flicker. Wafeln describes a swaying motion similar to undulating waves; the object seen is often enveloped in an eery light. According to folk tradition, Wafeln portends coming calamity to those who can perceive it. Waffle, waver and waft probably derive from this word.