Subject
Vessel motions are generated by its response; i.e. transfer functions (RAOs), to passing waves.
Vessel motions are important for identifying loads imposed by a mass on or in a ship’s structure and/or its equipment such as:
a) seafastenings for transporting goods and equipment from port to port, and;
b) specifying and sizing equipment for offshore operations.
Calculator
The vessel accelerations calculator determines linear and rotary motions of a vessel using classical harmonic theory or DnV Rules for the Classification of Ships (January 2012).
Vessacc provides a calculation method for both of the above alternatives, giving you displacements, velocities and accelerations in 6 degrees of freedom at the ship's centre of gravity and at any point you specify on its structure.
For help using this calculator see Technical Help
Vessel Motions Calculator  Options
Classical Harmonic
Calculates the motions of a ship’s centre of gravity and any point (‘P’) on its structure according to classical harmonic theory using trigonometric projection. This calculation theory is best suited to offshore operations.
You enter 
and the vessel motions calculator will provide: 


Surge @ CofG

Sway @ CofG

Heave @ CofG

Surge vel @ CofG

Sway vel @ CofG

Heave vel @ CofG

Surge acc @ CofG

Sway acc @ CofG

Heave acc @ CofG

Roll @ CofG

Pitch @ CofG

Yaw @ CofG

Roll vel @ CofG

Pitch vel @ CofG

Yaw vel @ CofG

Roll acc @ CofG

Pitch acc @ CofG

Yaw vel @ CofG

Surge @ 'P'

Sway @ 'P'

Heave @ 'P'

Surge vel @ 'P'

Sway vel @ 'P'

Heave vel @ 'P'

Surge acc @ 'P'

Sway acc @ 'P'

Heave acc @ 'P'

Wave elevation @ CofG

DnV Rules for Ships
Calculates the motions of any point (‘P’) on a vessel’s structure according to DnV’s rules for ships. This calculation theory is most appropriate for porttoport transit operations.
You enter: 
and the vessel motions calculator will provide: 


Common acceleration parameter

Surge acceleration

Swayyaw acceleration

Heave acceleration

Period of roll

Period of pitch

Angle of roll

Angle of pitch

Tangential roll acceleration

Tangential pitch acceleration

Vertical roll acceleration

Vertical pitch acceleration

Vertical acceleration

Transverse acceleration

Longitudinal acceleration

Vessacc includes a data import facility from CalQlata's RAO calculator
Check minimum system requirements