Tuesday, February 26, 2008

FIND COURSE TO STEER AND SPEED MADE GOOD


Determine the course to steer at a given speed to make good a desired course with this information: ship’s speed 12 knots, the desired course 095° , the current’s set 170° , and the drift 2.5 knots.

Solution: From point A draw course line AB extending in the direction of 095° (indefinite length).
From point A draw in the current line AC for the set 170° and drift 2.5 knots. Using C as a center, take the dividers, swing an arc of radius (ship’s speed 12 knots) CD, intersecting the line AB at D. Measure the direction of line CD (083.5° ). This is the course to steer. Measure the length of the line AD, 12.4 knots is the speed made good.