Minimum Mooring Requirements

Please Note:

These are the CMMA minimum requirements for any mooring assembly.  Going beyond these requirements might not only be advisable, but required, based on the depth of the mooring and the type of vessel using the mooring.

It is the mooring holder's responsibility to seek professional advice on the construction of their mooring assembly, or have their mooring assembly made by a professional mooring supplier or contractor.

This is to ensure that their mooring meets their individual requirements.

Sinker/Clump

Shall be a minimum of 500Kg. ±50kg

Shall be made of steel or cast iron.

Have an aperture through the clump that allows the ground chain to pass through and be fixed in a shackleless manner.

Ground Chain

A minimum diameter of 38mm.

A minimum length of 8 metres.

Have an aperture that enables the passing through of the riser chain in a choke connection method.

Riser Chain

A minimum diameter of 18mm when renewed, or less 20% wear during subsequent inspections.

Shall be new and unworn.

Shall have a welded loop or similar to enable the passing of the riser through itself, to attach via a “choke” method onto the ground chain.

Surface Riser Buoy

The mooring shall be equipped with a buoy that enables any connections to the vessel to be made above the water line.

The buoy shall be a make and model mandated by the CMMA, which currently is:

A ‘Norfloat MBS1’, or a buoy of a similar ‘chain through’ type and construction.

The buoy must be clearly marked with the mooring number.

General Configuration

No shackles are permissible to be used below the water line and any connections in the mooring assembly should be of a welded nature.

The use of swivels in the riser is not permissible.

April 2025