Vessel Motions Calculator v1

Price: £43.82 (£43.82 Inc. VAT)

Calculator for the motions of a vessel in waves


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.


go to the technical help page
go to the QandA page

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:
  • Longitudinal position
  • Latitudinal position
  • Vertical position
  • Angular wave velocity (encounter)
  • Surge response amplitude
  • Surge phase angle
  • Roll response amplitude
  • Roll phase angle
  • Sway response amplitude
  • Sway phase angle
  • Pitch response amplitude
  • Pitch phase angle
  • Heave response amplitude
  • Heave phase angle
  • Yaw response amplitude
  • Yaw phase angle
  • encounter period
  • angle through wave
  • wave profile height
  • 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 port-to-port transit operations.

You enter: and the vessel motions calculator will provide:
  • Longitudinal dimension
  • Latitudinal dimension
  • Vertical dimension
  • Vessel velocity
  • Vessel length
  • Vessel beam
  • Deck height
  • Vessel draft
  • Displacement
  • Metacentric height factor
  • Damping factor
  • Roll acceleration factor
  • Restricted service reduction
  • Common acceleration parameter
  • Surge acceleration
  • Sway-yaw 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

We accept the following payment methods

Credit Cards