BeaufortScale2

SCALE	DESCRIPTION	KM/HR	KNOTS	VISIBLE SIGNS	SAILING CRITERIA
0	Calm	<1	<1	Flat, calm sea. On land, smoke rises vertically, leaves are still	Dinghies should be heeled to reduce wetted area and allow the sails to form aerofoil shape. Cruisers need to use engines to make steerage way.
1	Light air	1-5	1-3	Slight rippling of the sea. Smoke drifts, wind vanes unaffected.	Dinghies can make gentle forward motion with flattened sails, and balanced to be slightly bow-down and heeled to leeward. Cruisers need engine power.
2	Light breeze	6-11	4-6	Small wavelets develop. Leaves rustle, flags and weather vanes stir. The wind can be felt on the face.	Dinghies can sail upright at a reasonable speed and with full sails. With 6 knots of wind, a good cruiser racer may take 3 to 4 knots; other cruisers need engine power.
3	Gentle breeze	12-19	7-10	Wave crests begin to break. Leaves move continuously, light flags are extended.	Ideal conditions for dinghies because there is sufficient wind and the waves are still quite small. Cruisers can make steady progress under sail.
4	Moderate breeze	20-28	11-16	Wave lengths increase, with frequent white horses. Most flags extended, light branches move and dust may be raised.	Good for experienced dinghy sailors but learners should go ashore. Most cruisers can reach hull speed; some need reefed mainsails and part-furled headsails.
5	Fresh breeze	29-38	17-21	Many breaking wave crests. Small, leafy trees begin to sway, tops of all trees move.	Excellent for experienced dinghy crews; the less experienced may be capsized. Ideal for cruisers, but light boats need to use smaller sails to reduce heeling.
6	Strong breeze	39-49	22-27	Large waves develop, with foamy crests and spray. Large tree branches move, wind whistles in telephone and electricity lines.	Most dinghy crews are at their limit; many will be overpowered. Many cruisers will head for shelter, with mainsails double-reefed and crews wearing harness.
7	Near gale	50-61	28-33	Waves heap and foam is blown downwind. Whole trees sway, and walking against the wind becomes tiresome.	Dinghies should stay on shore. Most cruiser crews will find it hard to cope and should seek shelter or, if gales are forecast, heave to and ride out the storm.
8	Gale	62-74	34-40	Waves become large with deep troughs and much blown foam. Twigs break off trees, and walking is difficult.	Dinghies should be securely tied down. Cruisers should have deeply reefed main and small headsails; all except essential crew should be securely below deck.
9	Strong gale	75-88	41-47	High foam-streaked waves with breaking crests. On land, roofs, chimneys and fences may be damaged.	Cruisers in danger of nock down. Even the most experienced of crews will have problems, and most will need to lower the sails and lash the tiller.
10	Storm	89-102	48-55	Waves very high with breaking crests and large, frothy patches of foam. Trees are uprooted; much structural damage.	Wave heights of 20 to 35 feet can capsize large cruiser racers lying a-hull. Breaking crests can pitch pole a large yacht running with or across them.
11	Violent storm	103-117	56-63	Waves become extremely high, and sea surface obscured by driving foam. Severe structural damage on land.	Extreme danger, especially when close to a shelving coast. Capsize and 90 deg. knockdowns possible. Keep well away from coastline if at all possible.
12	Hurricane	>117	>63	Huge waves. The sea becomes completely white and visibility is seriously affected by driving foam.	The worst possible danger. Survival is the most you can hope for, and your only priority.