When a floating body (a ship or a barge) floats in a wave train, it is subjected to inertial (acceleration) loads as it (the body) responds to the altering free surface. "Pitch" is the rotation (up and down) of the bow (front) and stern (back) about the center of the body. "Roll" is the rotation (side to side) about the long axis of the body.
Typically, piping systems subject to pitch and roll are analyzed using "static equivalent" methods where the loading is a "g" factor.
_________________________
Regards,
Richard Ay - Consultant