Shipboard Noise, Sleep Disturbance and Perceived Operational Safety in Maritime Cadets: A Two-Factor Model and Mediation Analysis with Implications for the Review of IMO Noise Limits

Seafarers inhabit acoustically hostile environments continuously across deployment rotations of four to six months, yet how shipboard noise relates to operational-safety risk is poorly characterised. We surveyed 242 maritime cadets with sea-service experience at Korea Maritime and Ocean University and applied factor analysis, structural regression and mediation modelling to the resulting cross-sectional, self-reported data. A two-factor model—Noise-Induced Sleep Disturbance and Fatigue (F1; α = 0.929) and Noise-Related Communication and Safety Impairment (F2; α = 0.871)—was retained over competing specifications on parsimony and interpretability grounds, with high reliability and supported discriminant validity (φ = 0.667), although absolute fit was modest (CFI = 0.865, RMSEA = 0.106) and the model awaits independent replication. F1 was strongly associated with F2 (β = 0.592, p < 0.001, R2 = 0.349), independent of academic department. An exploratory mediation analysis indicated that sleep disturbance and fatigue statistically accounted for 58% of the association between perceived noise burden and perceived safety impairment (indirect = 0.321, 95% CI [0.16, 0.49]), and 34% of cadets self-reported a noise-related near-miss. Across all shipboard spaces, cadets favouring stricter, WHO-aligned noise limits outnumbered those satisfied with current IMO ceilings by about 2.5 to 1. These cross-sectional findings are consistent with—but cannot causally demonstrate—a sleep–fatigue pathway linking shipboard noise to operational safety, and they offer stakeholder-derived input for future discussions of IMO Resolution MSC.337(91).