Dead Waters: Large amplitude interfacial waves generated by a boat in a   stratified fluid
  We present fluid dynamics videos of the motion of a boat on a two-layer or three-layer fluid. Under certain specific conditions, this setup generates large amplitude interfacial waves, while no surface waves are visible. The boat is slowed down leading to a peristaltic effect and sometimes even stopped: this is the so-called dead water phenomenon. 
Romain Vasseur, Matthieu Mercier, Thierry Dauxois