This entrapment then creates aerodynamic lift in addition to the planing (hydrodynamic) lift from the hulls.
Many times this is attributed to ground effect.
Theoretical research and full-scale testing of tunnel hulls has demonstrated the dramatic contributions of 'close-proximity ground effect' on enhanced aerodynamic lift/drag in operation of performance tunnel hull designs.
Formula 1 powerboats have a tunnel hull catamaran design allowing them to go faster.
Tunnel hulls are a common design in offshore powerboat racing.