This paper focuses on the accuracy of the “load per meter run “criterion which is used as a simple assessment for the acceptance of a specific docking operation regarding the structural safety of an unrated caisson floating dry dock. A candidate floating dock system in Port Said Shipyard is modelled in order to illustrate the procedure followed to attain a proper decision. The development of the 3D finite element model acquires the availability of the full technical data of the floating dock. All major docking operation phases are taken into account.  The adequacy parameter is a good measure to detect the suspicious locations within the dock's structure and identify the expected failure modes. The created 3D model is a useful tool that may be used in a trial and error process to attain a proper ballasting system to reduce stresses instead of rejecting the operation.  The present case study had showed that the “load per meter run “criterion may be highly simplified and can be quite inaccurate specially in the critical docking operations.