Definition
Developed for aircraft, it replaces the sea horizon with a bubble level so altitudes can be measured when no horizon is visible, such as in haze or at night. Accelerations from vessel motion displace the bubble, so accuracy at sea is markedly poorer than a marine sextant against a good horizon, typically several minutes of arc. Averaging over a timed interval reduces but does not eliminate the acceleration error.
Want to apply this on the water?
Ask Saily out loud for an example, a scenario or a simpler explanation.
Talk to Saily