I hope that these few lines can guide you in your training as a Marine Surveyor.
We recommend that you read the guidelines that are appended to the end of this post. Enjoy it!
General
Bollard pull reference:
We recommend that you read the guidelines that are appended to the end of this post. Enjoy it!
General
The following guidance notes apply to the bollard pull test of any towing vessel which the Surveyor is requested to approve or attend.
The safe working load of the test equipment, fittings and any connection points ashore shall be at least 10% in excess of the designed maximum continuous static bollard pull of the vessel.
Location
The water depth at the test location shall be at least 20 meters within a radius of 100 meters of the vessel.
If a water depth of 20 meters cannot be obtained at the test location, then a minimum water depth which is equal to twice the maximum draught of the vessel may be accepted. The owner of the vessel must be advised that the reduced water depth may adversely affect the test results.
The test location shall be clear of navigational hazards and underwater obstructions within a radius of 300 meters of the vessel.
The current shall be less than 0.5 meters/second from any direction.
The wind speed shall be less than 5 meters/second from any direction.
The condition of the sea at the test location shall be calm, without swell or waves.
Vessel
The draught and trim of the vessel shall be as near as possible to the draught and trim under normal operating conditions.
The propellers and fuel used during the tests shall be the same as the propellers and fuel used under normal operating conditions.
All auxiliary equipment such as pumps, generators and other equipment which are driven from the main engine(s) or propeller shaft(s) during normal operation of the vessel shall be connected during the test.
Test
The distance between the stern of the vessel and the shore shall be at least 300 meters.
If it is not possible to maintain a distance of 300 meters between the stern of the vessel and the shore, then a minimum distance which is equal to twice the waterline length of the vessel may be accepted. The owner of the vessel must be advised that the reduced distance between the vessel’s stern and the shore may adversely affect the test results.
Adequate communications shall be established between the vessel and instrument recording station.
The Continuous Bollard Pull (CBP) test shall be carried out at the manufacturer’s recommended maximum continuous rating of the main engines (100% MCR), for a period of 10 minutes with the vessel on a steady heading.
Whenever possible a maximum (MBP) test shall be carried out at the manufacturer’s maximum rating of the main engines (typically 110% MCR), for a period of 5 minutes.
When requested, continuous bollard pull may also be verified at different RPM and/or propeller pitch settings or with fewer propellers or engines in use.
The load cell used for measuring the bollard pull shall have an accuracy of ±2% for the average temperature observed during the test and shall have been calibrated not more than six (6) months prior to the test date. The calibration certificate shall be available.
An autographic recording instrument giving a continuous read-out of the bollard pull shall be connected to the load cell.
If no continuous record of the test is printed, then the bollard pull shall be the mean of consecutive readings recorded at 20 second intervals over the test period.
Bollard Pull Tests Acceptance
Bollard pull test certificates issued by Surveyor are acceptable, or by another recognized body provided that acceptable procedures for the tests are produced.
Bollard pull reference:
