A pivotal element in the effective application of STEM is Navigation Data Monitoring (NDM). When coupled with Line Operation Safety Assessment (LOSA), NDM contributes to proactive risk mitigation by identifying high-risk operations or practices. The STEM model serves various purposes: Safety Analysis Tool: Focuses on a single event, such as accident/incident analysis. Systemic Patterns Understanding: Examines systemic patterns within a large set of events, as in operational audits. Licensing Tool: Clarifies human performance needs, strengths, and vulnerabilities, aiding in defining competencies from a broader safety management perspective. Training Tool: Enhances the effectiveness of training interventions, contributing to organizational safeguards. Components of the STEM Model: The STEM model comprises three fundamental components for safe ship operation threats, errors, and undesired vessel states. It posits that ship operation crews, both on the bridge and in the engine room, must manage threats and errors inherent in everyday ship operations. These threats and errors carry the potential to lead to undesired vessel states, which, if not managed effectively, may result in unsafe outcomes, accidents, or incidents. Explanation of Threats, Errors, and Undesired Vessel States: STEM serves as the primary measure for Line Operations Safety Audit (LOSA) observation. The model emphasizes that threats, errors, and undesired states are critical events that frontline workers must manage to uphold safety and efficiency margins. Threats: Observable events or errors occurring outside the influence of frontline workers, demanding immediate attention for safe management. Examples include managing weather conditions, technical failures, reduced underwater clearances, or errors from other departments. Errors: Observable deviations by frontline workers from organizational or individual expectations or intentions. Examples include incorrect automation entries, failure to activate a protective system, checklist omissions, or neglecting critical briefings. Undesired States: Observable states induced by frontline workers exhibiting an apparent reduction in safety margins. Examples include exceeding berthing speed, deviations from the passage plan, or operating in extreme weather conditions, elevating the potential for incidents or accidents.