Wind

        Hull, superstructure, rigging, sail stowage, spray hoods and underwater shape all have a bearing on the load placed on the vessel by air load. Wind velocity aerodynamically increases with the square of the wind, if the wind strength doubles the load is multiplied by four and if it quadruples it goes up by twelve. It’s impossible to quantify the effect of wind caused by boats yawing and veering from side to side due to the tide trying to overcome wind or visa versa, what can be said is that these additional forces add greatly to the strain placed on both the mooring and boat parts. Additionally, within crowded mooring areas there is the additional hazard of ‘charging’* if there is too much scope allowed within the riser.

*The effect of a vessel being driven forward by the weight of the wind.

Tide

Generally tidal stream speeds are known, but the force on the mooring system can vary according to the boats underwater area, shape, the amount of marine fouling, and the aspect of the craft to the tidal stream.

Wave

Waves and swell have the most damaging effect on moorings. The various motions brought about by these conditions include violent pitching and rolling with its consequent stress on both the mooring assembly and boat equipment.

Undertow

As demand on available river space increases the practice of laying moorings ever nearer to navigation channels grows. The possibility of scouring should be always be considered. We are aware of a number of instances where freshly laid mooring systems have become untenable due to anchors/sinkers moving probably triggered by the river bed around them being washed away by undertow, this is can be caused by factors such as passing ships, speeding boats and dredging.

Overloading

Can be caused by  large craft using moorings laid for small boats or rafting!

Corrosion

Is an ever-present problem, it varies between locations to such an extent that identical moorings only short distances apart will be affected differently.