Also calculate the location along the length of the ship where the net force acts. Calculate all the environmental forces on the vessel from the beam side (either port or Starboard).Get the environmental parameters of the Quay – Wave height, wind speed and current speed.Get the vessel’s dimensions and cargo dimensions.The entire concept can be delineated in the following steps: Calculation Steps The next step will be to find out what line size and strength will be required to moor a vessel. This ensures that the entire load is distributed over two ropes on either side. Thus, a safer and more recommended solution is to have two ropes on either side, running to different bollards on the Quay Side.

Also, if the ropes are tied closer to the fwd end of the vessel, the aft end may be subjected to an undesirable yaw moment. However, this simplest solution, while feasible, doesn’t have any backup in case the rope on either side breaks. A simple way is to tie the vessel to the quay side using ropes, and the simplest solution is to use a rope on each side, running each from the Port or Starboard side of the vessel, and tied to a bollard on the Quay. This vessel will be subjected to environmental loads coming from the beam side of the vessel (athwartship) which will tend to drift it off. Thinking in very basic terms, the vessel will have its Stern pressing against the Quay (with fenders between the vessel and Quay to take the load). The vessel will be subject to external forces of wind, current and wave, and so it is important to design a mooring system which can overcome these forces. During these operations, it is important to hold the vessel in place when the loadout operation is being carried out. The Stern-on-Quay configuration can be used when there’s limited space available for the Port-on-Quay configuration, or when specialized operations like loadout are needed. In this article, we will analyse the first configuration – the Stern on Quay in more detail, and present a simplified method for calculating the line loads for a 4-point mooring pattern with the vessel’s Stern on Quay.

Configuration 2: with the vessel’s Port or Starboard side aligned with the Quay.īoth these configurations are shown in the sketches below.įigure 1 – Two different mooring arrangements at Quayįor each configuration, the mooring design has to be adequate to restrain the forces which the vessel experiences.

Configuration 1: with the vessel’s Stern aligned with the Quay.Two berthing configurations which are mostly used are: The berthing configuration depends on the geometry of the berth, and also on the available space depending on the traffic at the berth and size of the vessel. A vessel at berth experiences much lower forces compared to a vessel in the open sea due to the milder environment, but it still requires a mooring configuration suitable to the forces it experiences, and also suitable for the type of berthing configuration adopted.

Orcaflex mooring analysis