are defined by the six degrees of freedom
that a ship or boat can experience.
Heave : is the linear vertical (up/down) motion
Sway : is the linear lateral (side-to-side) motion
Surge : is the linear longitudinal (front/back) motion
Roll : is when the vessel rotates about the longitudinal (front/back) axis.
Pitch : is when the vessel rotates about the transverse (side-to-side) axis.
Yaw : is when the vessel rotates about the vertical (up-down) axis.
There are methods for both passive and active motion stabilization used in some designs. They can include static hull features such as skegs
and bilge keels
, or active mechanical devices like counterweights, anti-roll ballast tanks, and stabilizing fins
1) Society of Naval Architects and Marine Engineers (SNAME
), "Principles of Naval Architecture", 1989, Vol. III, Pg.41, Section 3 - Ship Responses to Regular Waves.