How to test mooring winch brake rendering?

As we introduced it in our e-mail newsletter No.4 ’Special Mooring Requirement for some Australian Ports’, recently there are cases that ships other than tankers or gas carriers are required to test its mooring winch brake rendering regularly and are required to submit the test record.

We explain test procedure of brake rendering test and its important points.

１．Before Testing

• A 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.
• Before testing a winch brake, the condition of the brake, its mechanism and the brake drum should be confirmed as satisfactory.  Any damage, failure or excessive wear should be rectified before testing takes place.
• It is strongly recommended that ship-specific instructions developed by the vessel’s Technical Managers are on board.

２．Purpose and Procedure

• The test itself is essentially a jacking test against the winch brake.
• When testing, the aim is to apply a hydraulic force to the winch drum equivalent to the 60% of the SDMBL on the first layer of the rope (for split drum winches) and to ensure that winch brake slips (or renders) at that point. Then, the tightened brake screw must be marked at the point it slips.
• It is not a load test to determine how strong the winch brake is, but a test to see that brake holds until 60% of the SDMBL. Applying more force causes slippage of the brake to ensure that winch brake remains the weakest point of the mooring system.

３．Common Mistake

• One common mistake when calculating the required hydraulic jack pressure, is that Line MBL is used as the reference rather than SDMBL.
• Another common mistake is that when the calculated hydraulic jack pressure is reached and brake is still holding, that the test is deemed successful. It must be clearly seen that after exceeding the calculated limit, the brake slips.

Rightship explain the detail of brake rendering test. please refer below link.
Lessons Learned: What is render testing? | Rightship