A mooring system can be composed of several components, including :

  • mooring lines,
  • mooring buoys,
  • clumpweights,
  • fairlead,
  • anchor,
  • etc…

Its general purpose is to restrict the motions of a floating structure (ship, platform, etc.) in a specified area. Mooring systems can be more complex than a single line connected to an anchor and fulfill multiple objectives.


(In construction)

A mooring line is used to connect different kinds of elements : floating structures, buoys, anchors, etc.

See line theory.

Mooring buoy

Mooring buoys are easy, pre-defined bodies, with already built-in model forces : non linear hydrostatic and linear damping forces. They are based on a spheric shape for their inertia distribution, collision box and visualization asset. Their CoG is defined at the center of the sphere. Their radius and density are to be specified at creation.

Hydrostatic force

They come with a simplified non linear hydrostatic force :

\[\mathbf{f}_{HS} (t) = - \rho_{water} V(t) \mathbf{g}\]


  • \(\rho_{water}\) is the water density,
  • \(\mathbf{g}\) is the gravity acceleration,
  • \(V(t) = \dfrac{\pi}{3} \left[ h(t) \times \left(3 \times R^2 - h(t)^2 \right) + 2 R^3 \right]\) is the immersed volume of the buoy,
  • \(h(t)\) is the immersed draft of the buoy.

This force is applied on the sphere CoG, which means it induce no torque.

Damping force

Mooring buoys posses a linear damping force, which diagonal damping coefficients must be specified at creation. See other damping for more information.


In construction (and development)


In construction (and development)

Soil Interaction

In construction (and development)