Articles - Mentally Calculating the Wind Correction Angle (Crab Angle) - Page 4

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Mentally Calculating the Wind Correction Angle (cont.)

IV - Comparing the mental estimation method with the exact formula

Although using the exact formula for calculating WCA would defeat the purpose of doing the mental estimation, we can use it here to compare and see how close our estimations were. The following formula produces an exact result:

a) WS = 10 knots; AWA = 40^o.

Substituting the values in the equation:

The WCA calculated by the formula is 3^o. This is the same result we got using mental estimation.

b) WS = 20 knots; AWA = 40^o.

Substituting the values in the equation:

The WCA calculated by the formula is 6^o. This is the same result we got using mental estimation.

c) WS = 5 knots; AWA = 40^o.

Substituting the values in the equation:

The WCA calculated by the formula is 1^o. This result we got using mental estimation was 2^o so we are off by 1^o.

d) WS = 10 knots; AWA = 70^o

Substituting the values in the equation:

The WCA calculated by the formula is 4^o. This is the same result we got using mental estimation.

e) WS = 30 knots; AWA = 90^o.

Substituting the values in the equation:

The WCA calculated by the formula is 13^o. This result we got using mental estimation was 12^o so we are off by 1^o.

f) WS = 20 knots; AWA = 10^o

Substituting the values in the equation:

The WCA calculated by the formula is 0^o. This result we got using mental estimation was 2^o so we are off by 2^o.

g) WS = 27 knots; AWA = 63^o.

Substituting the values in the equation:

The WCA calculated by the formula is 11^o. This result we got using mental estimation was 10^o so we are off by 1^o.

h) WS = 3 knots; AWA = 45^o

Substituting the values in the equation:

The WCA calculated by the formula is 1^o. This result we got using mental estimation was 2^o so we are off by 1^o.

i) 12 knots; AWA = 20^o

Substituting the values in the equation:

The WCA calculated by the formula is 2^o. This is the same result we got using mental estimation.

j) WS = 48 knots; AWA = 70^o

Substituting the values in the equation:

The WCA calculated by the formula is 20^o. This is the same result we got using mental estimation.

k) WS = 63 knots; AWA = 25^o

Substituting the values in the equation:

The WCA calculated by the formula is 12^o. This result we got using mental estimation was 13^o so we are off by 1^o.

Notice how close our estimates were, even using the simpler table on the right for the AWA correction!

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