Bollard Pull Calculator | Calculations and Applications in Marine Engineering

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Bollard Pull is a critical concept in marine engineering, primarily used to measure the pulling or towing capacity of tugboats and other maritime vessels. It is defined as the force exerted by a vessel under full power on a shore bollard through a towline and is usually measured in tonnes. The towing capacity is essential for various maritime operations like towing ships, oil rigs, or assisting in maneuvering other vessels. This concept is mainly relevant to marine engineering and naval architecture.

Enter the engine power (in kW) and propeller efficiency (between 0 and 1) to calculate the Bollard Pull (in tonnes).

Bollard Pull Calculator
Bollard Pull Calculator Results (detailed calculations and formula below)
Bollard Pull = tonnes
Bollard Pull (b) = Engine Power (p) × Propeller Efficiency (e) × 0.101972/9.81
b = p × e × 0.101972/9.81
b = × × 0.101972/9.81
b = /9.81
b =
Bollard Pull Calculator Input Values
Engine Power (p) kW
Propeller Efficiency (e) %

Example Formula

One of the standard formulas to calculate Bollard Pull takes into account the Engine Power and Propeller Efficiency:

Learn about Bollard Pull, its importance in marine engineering, the formulas involved, and its real-life applications
Bollard Pull (tonnes) = (Engine Power (kW) × Propeller Efficiency × 0.101972) / 9.81


  1. Bollard Pull: The pulling or towing capacity of the vessel in tonnes.
  2. Engine Power: The power output of the vessel's engine in kilowatts.
  3. Propeller Efficiency: The efficiency of the propeller as a decimal between 0 and 1.

Impact on Society

The Bollard Pull calculation is fundamental in maritime operations. It ensures the safety and efficiency of towing operations, crucial for both commercial and rescue operations. Beyond marine engineering, this concept is also relevant in offshore engineering and the oil & gas industry. It helps in moving oil rigs and conducting offshore rescues. By ensuring that vessels are used within their safe towing capacity, Bollard Pull calculations play a significant role in preventing maritime accidents.

Real Life Application in Industry

In the shipping industry, Bollard Pull is extensively used to assess the capability of tugboats. For instance, a large container ship may require assistance to enter a narrow harbor. A tugboat with adequate Bollard Pull will be employed to safely guide the ship into the harbor without incident. Additionally, in offshore oil exploration, Bollard Pull is vital for positioning and moving floating oil platforms, which can weigh several thousand tonnes.

Key Individuals in the Discipline

Though there are no specific individuals associated with the concept of Bollard Pull, marine engineering itself has been shaped by several influential figures. For instance, Robert Napier is considered the "Father of Clyde Shipbuilding" and played a critical role in the development of steam navigation in the early 19th century. His work laid the foundation for modern marine engineering practices.

Interesting Facts

  • Bollard Pull testing is performed with the vessel's towing equipment secured to a shore bollard, and the engines are gradually applied full power to measure the maximum pulling force.
  • Some of the strongest tugboats in the world have a Bollard Pull exceeding 200 tonnes, capable of towing large ships and oil rigs.
  • Bollard Pull is also an essential factor in salvage operations, especially when salvaging large sunken vesselsor wreckage.


Bollard Pull is an integral concept in marine engineering, playing a vital role in towing and maneuvering of ships and other maritime structures. By calculating the Bollard Pull, marine engineers can ensure safe and efficient maritime operations. It is a practical application of engine power and propeller efficiency and is essential for tugboats, salvage operations, and offshore industries. As marine traffic and offshore exploration continue to grow, understanding and effectively utilizing Bollard Pull will continue to be a critical aspect of marine engineering.