Health, severity and failure probability
How a sensor reading becomes an alert with odds and a time window.
Vessel health
Each vessel has one health state, shown as the ring around its marker on the fleet map.
| Health | Meaning |
|---|---|
| ok (teal) | No open critical or high alert |
| warning (amber) | At least one open high alert, no critical |
| critical (coral) | At least one open critical alert |
Medium and low alerts show in the queue but do not change the ring.
Readings, prediction and normal band
For each sensor channel the model stores, every hour, the actual reading, the predicted value and a normal band around it. A reading outside the band is an anomaly. On MV Aldersea in the demo, the main engine bearing reads 101.2 °C against a prediction of 89.9 °C: 11.3 °C above.
Channels in this build: main engine bearing and exhaust temperature, turbocharger RPM, auxiliary engine lube oil pressure, boiler efficiency, shaft vibration, fuel purifier differential pressure, speed and fuel use.
Failure probability
The model measures how far a channel has drifted, in standard deviations (z), and how fast the drift grows per day (slope). The probability of failure within the window is:
p = 1 / (1 + e^−x), x = 0.9 × (z − 3.2) + 0.3 × slopeA drift of 3.9 σ that is rising quickly lands near 72 %.
Window
The window is how many days the failure is expected within. It gets shorter as the probability rises:
window_days = round(4 + 18 × (1 − p))So it ranges from 4 days (p = 1) to 22 days (p = 0).
Severity
Each alert has a severity: critical, high, medium or low. Critical alerts sit at the top of the queue and offer Notify crew.
Status
An alert moves through open → acknowledged → crew_notified → resolved, or is dismissed. Acknowledging needs edit. Notifying the crew, and dismissing a critical alert, need publish.
The model in this build is a fixed heuristic, not a trained model. Probabilities and windows in the demo are illustrative. A trained model per component comes before any pilot.
Users cannot change the severity, probability or window of an alert. Only the model service writes them.