The purpose of this Lessons Learned and Best Practice circular is to assist operators and crew in appreciating the benefits of regular Mooring Winch Brake Rendering Testing, and also share some of the common misunderstandings we have observed.
Although Mooring Winch Render Testing has been established practice in the tanker industry for many years, we are seeing more and more dry bulk terminals (particularly for Iron Ore and Coal exports) requesting that vessels calling at their terminals undertake periodic testing as per tanker practice.
Read moreRender testing is a periodic load test and calibration of a mooring winch brake at a load based on the Equipment Number (EN) assigned to the ship.
When moored, winch brakes and lines are expected to keep the vessel safely alongside. When environmental parameters change due to factors such as wind, current, swell, passing vessel surge, excessive list and trim, the winch brakes should be set as the weakest point of the mooring system. Rather than parting mooring lines or damaging mooring winch structures and fittings, the winch brakes should render (or slip) in a predetermined and controlled manner prior to exceeding the EN parameters so that the vessel can subsequently be brought back alongside safely.
Regular winch brake render testing and calibration should significantly contribute to safe mooring.
When a vessel is moored the winch brakes and lines are so designed to keep the vessel safely alongside within certain environmental parameters. Each vessel at the design stage is assigned an “EN” (Equipment Number / Numeral) by Class. The EN sets a Ship Design Minimum Breaking Load (SDMBL) which then determines minimum requirements for Mooring Winch Heaving Speed, Brake Holding Capacity, Mooring Rope Minimum Breaking Load and the Minimum Number of Mooring Ropes.
Read moreA test kit should be provided on board by the ship builder or by the Mooring Winch manufacture along with full instructions.
Testing should be carried out under the supervision or in the presence of a responsible person familiar with the operation of the winches, the test procedure and the ship’s Safety Management System.
Read moreIt is of utmost importance that the correct calculation is used for the type of mooring winch being tested.
Split Drum Mooring Winches must use the calculation based on one layer of line on the tension side of the split drum, such as to replicate a normal moored condition of maximum one layer of rope on the tension drum.
Read moreWhen the test is completed and the brake setting calibrated, the winch will need to be marked with a marking device to ensure that the brake is applied to the same torque at every mooring operation.
The marking device should be so designed such that further tightening in emergency situations is not impeded, and of suitable construction to remain in position and in good condition between routine tests. Examples of unacceptable and acceptable marker designs are shown below:
Read moreThe mooring winch brake rendering test should be carried out at intervals more frequently than only once every five years, preferably on an annual basis, and:
Procedures for testing mooring winch brakes, including a risk assessment should be made available on board and ship’s crews must be provided with appropriate training to conduct the test safely.
Training must at least cover below:
Read moreWhere do I find the SDMBL for my vessel?
This should be stated on the Mooring Arrangement Plan. If it is not (as may sometimes be the case for older vessels), then it is recommended that you consult with the vessel’s Classification Society.
What is the difference between the Maximum Brake Holding Capacity and the Operational Minimum Brake Holding Load?
The Maximum Brake Holding Capacity (normally set at 80% of the SDMBL) is the designed maximum holding of the winch brake whereas the Operational Minimum Brake holding Load (normally set at 60% of the SDMBL) is the normal operating Brake Holding (or rendering) Load.
Read moreOCIMF – Mooring Equipment Guidelines (4th edition)
ISO 3730:2012 – Shipbuilding and marine structures — Mooring winches
OCIMF – Effective Mooring (4th edition)
INTERTANKO – Guidance on Line Management Plans (LMP)
INTERTANKO – Guidance on Mooring System Management Plans (MSMP)
Article written by:
Yucel Yildiz, Vetting Superintendent
Marc Forster, Global Marine Standards Manager