Bollard Pull is the amount of force exerted by a tug upon a towing line with which the tug is connected to a bollard on the shore, and while the tug is not in motion. Bollard Pull value is measured in tons. This value is obtained from a device called dynamometer and it is a direct indicator of the capability and power that a tug has in tugging various vessels and objects. Prior to the construction of the ship, computer simulations and formulas are frequently used in order to obtain an approximate Bollard Pull value that the vessel will possess. The process of a proper Bollard Pull test is controlled by the world's classification societies, and all of them have their own recommended guidelines for carrying out the test. The Bollard Pull is always the strongest at the very beginning of the test, when the propeller moves in calm water, after that it falls down and stabilizes on a certain smaller value. That value is called Sustained Bollard Pull. This value is then recorded in the Bollard Pull Certificate and is verified by the present classification society. While moving through water and tugging other objects at a certain speed, the tug's tugging efficiency is affected by many different internal and external factors. Therefore it is always important to carefully study the characteristics of the area in which the ship will be sailing, the description of the task to be performed, and the characteristics of the towed object and the tug itself. Today, the Bollard Pull test is used to test the power of all types of tugboats, from harbour tugs, escort tugs, platform supply tugs, up to AHTS (Anchor Handling) tugs. The AHTS tugs have become very important because of the rapid development of offshore drilling platforms. The duty of an AHTS tug is to handle the heavy anchors which are holding the offshore platform in her position. This task is often carried out in severe sea conditions, with high waves and strong winds present. The AHTS vessel possesses, because of such working conditions and the difficulty of the tasks demanded from her, exceptionally strong main engines relative to her size. It is because of this that AHTS tugs possess the strongest towing capability of all types of tugs, which makes them particularly interesting when talking about the Bollard Pull test.