Wind Speeds and Required Sails
Beaufort scale Speed knots mph, km/h sail lore
0 calm <1 <1 no steering way
1 light air 1-3 1-3, 1-5 just steering way
2 light breeze 4-6 4-7, 6-11 full sail, 1-2 knots
3 gentle breeze 7-10 8-12, 12-19 full sail, 3-4 knots
4 moderate breeze 11-16 13-17, 20-28 full sail, 5-6 knots
5 fresh breeze 17-21 18-24, 29-38 + royals
6 strong breeze 22-27 25-30, 39-49 + full topgallants
7 high wind 28-33 31-38, 50-61 + reefed topgallants
8 gale 34-40 39-46, 62-74 + topsails
9 strong gale 41-47 47-54, 75-88 + reefed topsails, courses
10 storm 48-55 55-63, 89-102 + double reefed topsails and reefed courses
11 violent storm 55-63 64-73, 103-117 storm sails only
12 hurricane => 64 => 74, => 118 no sails