Galvanic Fatigue Calculator

Galvanic Fatigue Calculator turns peer-reviewed sleep science into a practical passage-planning tool for offshore sailors.

Enter your crew size, route, departure time, and pre-departure sleep — the app simulates hour-by-hour fatigue across every watch, expressed as Blood Alcohol Concentration equivalent (BAC%), the standard metric for cognitive impairment in occupational fatigue research.

Under the hood, the app runs the McCauley Unified Model (McCauley et al., 2009, 2013; Ramakrishnan et al., 2016) — the same two-process biomathematical engine used in operational fatigue-risk management for aviation, shipping, and the military. It models homeostatic sleep pressure and the slow allostatic lower asymptote with closed-form analytical solutions, and layers circadian modulation on top.

Features
• Crew sizes 1–4 with auto-generated watch schedules
• Route, speed, and duration planning
• Sea-state selector: calm, moderate, rough, storm
• Real-time fatigue gauge 0–0.20% BAC
• Hour-by-hour chart and per-crew breakdown
• Compare mode (what happens with one more crew?)
• Share results
• Languages: English, Spanish, French, German, Italian

Free. No third-party ads. No trackers.

Recent changes:
First release. Biomathematical crew-fatigue modelling for offshore passages, expressed as BAC equivalent, with per-crew watch schedules.