Michell and Hogner models of far-field ship waves

•Consider farfield waves and wave drag predicted by Michell and Hogner theories.•Michell and Hogner theories predict nearly identical transverse waves.•However, divergent waves, dominant at high Froude numbers, can differ significantly.•Michell and Hogner predictions differ less for catamarans than for monohull ships. The far-field waves, and the related far-field wave drag, predicted by the Michell or Hogner theories are considered. These two classical theories are found to predict nearly identical transverse waves for all practical cases. However, the Michell and Hogner models predict divergent waves—dominant at high Froude numbers—that can differ significantly. Differences between the far-field waves predicted by the Michell and Hogner models are much smaller for catamarans, for which lateral interferences between the twin hulls overwhelm lateral interferences between the port and starboard sides of the hulls, than for monohull ships. Moreover, differences between the divergent waves predicted by the Michell and Hogner theories are larger for higher Froude numbers, bigger beam/length ratios, smaller draft/length ratios, or larger separation distances between the twin hulls of a catamaran.