"Semi-displacement / Semi-planing Hulls
Semi-displacement or semi-planing hulls have features of both planing and
displacement hulls. They have a maximum hull design speed. Exceeding this
speed can result in erratic handling and unstable operation. There is not
one hull design characteristic that differentiates semi-displacement from
semi-planing hull. The greater the hydrodynamic lift and higher the hull
design speed the more likely it will be referred to as a semi-planing hull.
"

Erratic handling and unstable operation!!!

Erratic handling and unstable operation!!!