LEEWAY
Leeway is not an error of the compass, but it has to be compensated for in steaming any distance. Hence it is mentioned here. A ship steaming with a strong wind or current abeam, will slide off to the leeward more or less. Hence, her course will have to be corrected for Leeway as well as for Variation and Deviation.
Put in your Note-Book:
Leeway on the starboard tack is the same as westerly Variation. Leeway on the port tack is the same as easterly Variation. This is apparent from the following diagram:
As the wind, blowing from the North, hits the left hand ship, for instance, on her starboard side, it shoves the ship to the left of her true course by the number of points or degrees of leeway.
Leave a space and put the following heading in your Note-Book:
I. Complete rule for converting a compass course into a true course:
1. Change the compass course into a new compass reading.
2. Apply Easterly Variation and Deviation +.
3. Apply Westerly Variation and Deviation -.
4. Apply port tack Leeway +.
5. Apply starboard tack Leeway -.
II. Complete rule for converting a true course into a compass course:
1. Reverse the above signs in applying each correction.
I will now correct a few courses, and these are to be put into your Note-Book:
| C Cos | Wind | Leeway | Dev. | Var. | New | Old |
|---|---|---|---|---|---|---|
| N x E | NW | ½ pt. | 5° E | 10° W | 12° | N 12° E |
| S 67° E | S | 1 pt. | 3° W | 5° E | 104° | S 76° E |
| E x N | SE | ½ pt. | 5° W | 10° E | 78° | N 78° E |
| W x N | NW | 1½ pts. | 1° E | 15° E | 280° | N 80° W |