This calculator is designed to
calculate the Course to Steer when a sailboat is sailing across, against
or with a current. Not all courses are possible and some are
impractical since the sailboat will not make significant headway.
The sailboat's speed as read on the GPS is a combination of
both the current and boat power, as read on the boat's tachometer or
knotmeter (the
instrument on a sailboat which measures distance and is used to compute
speed is called a "log" ) is reflective of the boat's power (it's speed
in relationship to the water). This latter value is used in field #2 of
the calculator.
The effects of current must be accounted
for in order to maintain the desired heading. If a boat is traveling 6
knots in relationship to the water and is sailing against a 3 knot
current, 45 degrees off the bow, the current will push the boat 28.7
degrees off the desired course (course to make good) with a
speed of advance of 4.4 knots.
Go To: Current Deviation Calculator.
To maintain the proper heading one will have to sail into the current
20.7 degrees resulting in a predicted speed of advance of 3.5
knots. (See the below calculator)
