Corrected Waypoint ETA
Compute ETA along a waypoint track while allowing for current: the boat first cancels the cross-current component, and its remaining along-track speed is combined with the current's along-track component.
Description
Compute ETA along a waypoint track while allowing for current: the boat first cancels the cross-current component, and its remaining along-track speed is combined with the current's along-track component.
Corrected Waypoint ETA is a focused tool for the following task. Compute ETA along a waypoint track while allowing for current: the boat first cancels the cross-current component, and its remaining along-track speed is combined with the current's along-track component. It reports Speed over ground, ETA from the values you provide rather than inventing measurements, coefficients, or professional judgment that are not part of the input.
When to use Corrected Waypoint ETA
Use this sailing calculation for planning or education when the vessel, units, reference directions, environmental conditions, and assumptions are explicitly known.
- Boat speed (kt)
- Required number in kt. Boat speed through the water.
- Course (°)
- Required number in °. Desired course over ground to the waypoint.
- Current (kt)
- Required number in kt. Current strength.
- Current set (°)
- Required number in °. Direction the current flows toward.
- Distance (NM)
- Required number in NM. Distance to the waypoint over ground.
The cited overview of Navigation supplies background for the terminology and domain context used by this tool.1
How Corrected Waypoint ETA works
Compute ETA along a waypoint track while allowing for current: the boat first cancels the cross-current component, and its remaining along-track speed is combined with the current's along-track component. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.
- Speed over ground (kt)
- Returned number in kt. Resulting speed over ground with current applied.
- ETA (h)
- Returned number in h. Hours until the waypoint at that speed over ground.
Limitations and assumptions
- Vessel design and loading, sea state, wind, current, tide datum, weather, chart accuracy, equipment, crew, and safety margins can make real conditions differ from a simplified result.
- Current must be at least 0.
- Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.
Alternative or Complementary approaches
Cross-check current charts, tide and weather services, instrument data, vessel manuals, and applicable navigation rules, and retain a conservative alternative plan.
References
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Navigation — Wikipedia contributors
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