Available calculators:

Celestial Navigation:
- Altitude Correction for Air Temperature
- Altitude Correction for Atmospheric Pressure
- Altitude Factors & Change of Altitude
- Compass Error from Amplitudes Observed on the Celestial Horizon
- Compass Error from Amplitudes Observed on the Visible Horizon
- Latitude and Longitude Factors
- Meridian Angle and Altitude of a Body on the Prime Vertical Circle
- Pub 229
- Table of Offsets

Conversions:
- Chart Scales and Conversion for Nautical and Statute Miles
- Conversion for Meters, Feet and Fathoms

Distance:
- Dip of Sea Short of the Horizon
- Distance by Vertical Angle Measured Between Sea Horizon and Top of Object Beyond Sea Horizon
- Distance by Vertical Angle Measured Between Waterline at Object and Sea Horizon Beyond Object
- Distance by Vertical Angle Measured Between Waterline at Object and Top of Object
- Distance of an Object by Two Bearings
- Distance of the Horizon
- Geographic Range
- Length of a Degree of Latitude and Longitude
- Meridional Parts
- Speed for Measured Mile and Speed, Time, and Distance
- Traverse Table

Log and Trig:
- Logarithmic and Trigonometric Functions

Sailings:
- Great Circle Sailing
- Mercator Sailing

Time Zone Table:
- Time Zones, Zone Descriptions, and Suffixes

Weather Data:
- Barometer Measurement Conversions
- Correction of Barometer Reading for Gravity
- Correction of Barometer Reading for Height Above Sea Level
- Correction of Barometer Reading for Temperature
- Direction and Speed of True Wind
- Relative Humidity and Dew Point
- Temperature Conversions

// Option A //

To download Nautical Calculator mod from HappyMod.com.
You need enable the option "Unknown Sources".
1. Click on the above link to download Nautical Calculator mod APK.
2. Save the file in your device Downloads folder.
3. Now tap on Install and wait for the installation to finish.
4. Once it is done, open the game and start playing it right away.

// Option B //

To download Nautical Calculator from HappyMod APP, you can follow this:
1. Open your browser and download the HappyMod APK file from HappyMod.com - the only official website of HappyMod.
2. Open Android Settings and go into Privacy or Security.
3. Tap the option to Allow Unknown Sources and enable it.
4. Go to your Android downloads and tap the APK file.
5. Follow the directions on the screen to install it.
6. Search Nautical Calculator in HappyMod App.