### COURSE and CURRENT - V.29

calculate the course when a current exists

(COURSES: Degrees, SPEED: knots)

**COURSE and CURRENT, Explanation **

This program calculates the triangle of a ships **course-through-water** (CTW) under some ** current ** (DUC)
giving finally a ** course-over-ground** (COG).
Enter first the ships **true** course and speed through the water, and then eventually the current and its speed and/or the desired course-over-ground.
If course-over-ground is not defined, this will be calculated by the program.
On the other hand, if course-over-ground is specified, the program will re-calulate course-through-water with the given value of speed.
In that latter case, the input for course-through-water is ignored. -

(As the vector-relation *CTW + DUC = COG* holds, you may use this program to eventually calculate the current *DUC* from the course-data:
*-CTW + COG = DUC*. The minus-sign is handled by adding 180° to *CTW* before entering, but keeping the corresponding speed.)
The ship is assumed to move forward only.

**Copyright**

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the license or any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License
(www.gnu.org/licenses/) for more details.

*If errors are encountered, kindly send a note to info@ocean-navigation.de*.
Author: Heiner Müller-Krumbhaar
*- Last update 18.may.2023.*