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BOLLARD PULL TEST
With the arrival of 2023, a new term has also been introduced in the Greek maritime reality.
Bollard Pull. What is it?
The Bollard Pull test is the capability of a tugboat to exert zero-speed pulling force. The test is recorded in tons of pulling force and expresses the force with which the tugboat can tow.
Ideally, the pulling test is performed during the construction of the tugboat and certified by naval surveyors. Pulling tests are also carried out after major engine overhauls.
Dynamometers are used for bollard pull test, force and load control, including drag force measurement.
With our knowledge and your power, we can produce a reliable result.
BOLLARD PULL TEST definitions
The Maximum Bollard Pull, also called “Static Bollard Pull,” is the maximum recorded tension achieved shortly after the test’s commencement over a period of approximately one minute. Determining MBP takes place with the maximum engine output, optimum propeller pitch, and during working in still water.
The Steady Bollard Pull, also called “Continuous Bollard Pull,” is the remaining steady traction force after the performance decreases from the maximum bollard pull force. The performance reduces due to cavitation and propeller slip once the water is streaming through the propeller representing the continuously maintained tension in the towing wire. The SBP is measured for a period of about 10 minutes and not less than 5 minutes at the times when the tug’s pull and direction are steady.
The Effective Bollard Pull is the traction force that the tug can develop in an open seaway. The calculation of EBP is not achievable during the bollard pull test; therefore, the EBP is calculated based on a fraction of the steady bollard pull SBP considering the losses due to environmental and external factors. Typically, EBP is estimated to be 75% of SBP.