Use this sailing calculation for planning or education when the vessel, units, reference directions, environmental conditions, and assumptions are explicitly known.

Set (°)

Required number in °. Direction toward which the current flows.

Drift (kt)

Required number in kt. Speed of the current.

Course (°)

Required number in °. Intended course through the water.

The cited overview of Tide supplies background for the terminology and domain context used by this tool.^[1]

Resolve a tidal diamond set and drift into components along and across the boat's course. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Along-course component (kt)

Returned number in kt. Current component along the course.

Cross-course component (kt)

Returned number in kt. Current component across the course.

• 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.
• Set must be at least 0.
• Set must be no greater than 360.
• Drift must be at least 0.
• Course must be at least 0.
• Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.

Cross-check current charts, tide and weather services, instrument data, vessel manuals, and applicable navigation rules, and retain a conservative alternative plan.

• Set and Drift Correction Calculator

  Calculate current set and drift by subtracting the vessel's through-water velocity vector from its observed over-ground velocity vector.

• Course Over Ground Calculator

  Calculate the resulting course over ground from vessel motion combined with current set and drift.

• Current Gain Loss Calculator

  Calculate the distance gained or lost to the current along the course, with a favorable set positive and an adverse set negative.