1-3 = 19 km/h or less 10 knots or less
4 = 20 - 29 km/h 11-16 knots
5 = 30 - 39 km/h 17-21 knots
6 = 40 - 50 km/h 22-27 knots
7 = 51 - 62 km/h 28-33 knots
8 = 63 - 75 km/h 34-40 knots
9 = 76 - 87 km/h 41-47 knots
10 = 88 - 102 km/h 48-55 knots
11 = 103 -117 km/h 56-63 knots
12 = 118 km/h or more 64 knots or more