A SUBSTANTIVE MODEL OF THE TURNING CIRCLE OF A LARGE SAILING VESSEL, WHICH INCLUDES “WEARING” AND “TACKING” TURNS
https://doi.org/10.33815/2313-4763.2025.2.31.209-225
Abstract
The object of the study is the process of turning a large sailing vessel with square-rigged sail arrangement. The pivot point plays a significant role in the process of turning a vessel. Turning a large sailing vessel differs from turning a vessel with a mechanical engine. For a vessel with a mechanical engine, turning is performed by simply shifting the rudder, and for a sailing vessel, especially large and square-rigged, performing a turn often requires a maneuver involving the adjustment of the sails, and sometimes two separate maneuvers.
According to the new concept, the turn is performed using a three-point scheme, namely: the center of gravity of the vessel is calculated. From the center of gravity, the position of the center of rotation is calculated, which is displaced from the center of gravity towards the oncoming water flow. From the center of rotation, the lever arms of the lateral forces that affect the vessel are calculated. If the force is one, the position of the pivot point of rotation is on the opposite side from the point of application of the lateral force relative to the center of rotation. In the case of two or more forces, the total moments of the lateral forces acting clockwise and counterclockwise relative to the center of rotation are calculated. Whichever total moment is greater determines the direction of the vessel’s turn. In order for the vessel to turn in the desired direction, it is necessary that the moment of the lateral force of the rudder exceeds the moment of the lateral force of the sails.
When turning a sailing vessel, two lateral forces act: the rudder and the sails. In the case of two or more forces, the total moments of the lateral forces acting clockwise and counterclockwise relative to the center of rotation are calculated. The vessel turns in the direction of the greater total moment. Therefore, for the vessel to turn in the desired direction, the moment of the rudder’s lateral force must exceed the moment of the sails’ lateral force.
As a result of both theoretical research and practical experiments, a new scheme for turning a large square-rigged sailing vessel was invented, taking into account the latest research, which is presented in this article.
These results can be used when maneuvering square-rigged sailing vessels in various sailing conditions.
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