Detailed Great Circle Calculations & Marine Route Planning
Great Circle & Mercator Sailing · Middle Latitude · Tidal Streams · Stability & Heeling · Gyro Errors · Cross Bearings · Practical Seamanship · Route Planning (Rhumb line)
Great Circle Sailing
Compute complete great circle routes, vertex, courses, distances, rhumb line segments and composite sailing.
Start →Tools
Convert temperatures (°C, °F, K, Rankine), distances and other helpful utility functions for daily navigation tasks.
Start →Route Planning
Calculate nautical miles from departure to arrival using accurate rhumb line sailing computations.
Start →Middle Latitude Sailing Calculation
Middle Latitude Sailing is a practical method for routes in mid-latitudes, using the mean of the departure and arrival latitudes to calculate both true course and distance. This method provides an efficient compromise between plane sailing and great circle navigation.
Start →Mercator Sailing Calculation
Mercator Sailing provides a complete and transparent rhumb-line calculation using differences in latitude and longitude together with meridional parts. All intermediate values such as ΔLat, ΔLong, meridional parts, departure, course angle and final distance are displayed.
Start →Gyro Speed Error
This tool calculates the gyrocompass speed error based on ship’s speed, heading and latitude and shows all computation steps.
Start →Rolling Period Test
The Rolling Period Test helps determine the natural rolling period and gives an approximate indication of initial stability (GM).
Start →Record of Employment
Create, edit and download a complete Record of Employment (RoE) online.
Start →GM Approximation Tool
Estimate your boat’s metacentric height (GM) based on heel angle and righting moment.
Start →Rhumb Line Route Planning
Check how many nautical miles it is from your departure port to your destination port using accurate rhumb line sailing calculations. The tool provides courses and distances suitable for practical voyage planning.
Start →Wind Heeling Calculator
Estimate wind heeling moment and expected heel angle using a smoothed GZ curve.
Start →Height Moment Calculation
The Height Moment Calculation determines the effect of vertical weight shifts on the ship’s center of gravity and stability.
Start →Tidal Stream Calculation
Practice tidal stream calculations through three Tasks. Each tab covers a Task, including current calculations and drawing current triangles (set and drift).
Start →Bearings & Position Fixing
Practice taking bearings directly on the chart and calculating position fixes. At this stage, the focus is on cross bearings; additional bearing methods will be introduced later.
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