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Updated January 23, 2007
Beaufort Wind Scale*
|
| F | Knots1 |
Km/hr2 |
Term | Advice | Open Sea | Land/Marina |
| 0 | 0-1 |
0-2 |
Calm | Sailboats can't sail. | Mirror. | Smoke rises vertically. |
| 1 | 1-3 |
2-5 |
Light air | Sailboats just have steerage, light spinnaker. | Scale ripples, no crests. | Smoke indicates direction. Vanes don't move. |
| 2 | 4-6 |
6-10 |
Light breeze | Wind fills sails, travel 1-2 knots. | Small wavelets, crests glassy, do not break. | Feel wind on face. Leaves rustle. Vanes show direction. |
| 3 | 7-10 |
11-16 |
Gentle breeze | Sailboats heel. | Large wavelets, crests break, whitecaps begin. | Small flags extended. Leaves move constantly. |
| 4 | 11-16 |
18-26 |
Moderate breeze | Sailboats at hull speed, use full sail. | Small waves 0.5 - 1.25 m, numerous whitecaps, frequent white horses. | Dust, loose paper raised by wind. Small branches start bending. |
| 5 | 17-21 |
27-34 |
Fresh breeze | Shorten sails. | Moderate & longer waves 1.5 - 2.5 m, whitecaps & some spray. | Small trees react to wind, crested wavelets inland waters. |
| 6 | 22-27 |
35-43 |
Strong breeze | Small craft warning 20-33 knots. Small sailboats head to shore. | Larger waves 2.5 - 4 m, numerous whitecaps, much spray. | Wind whistles. Most branches moving in trees, wind whistles in wires, umbrellas hard to use. |
| 7 | 28-33 |
45-53 |
Near gale | Sailboats remain in harbour. Double up on docklines and add extra fenders. | Sea heaps up, waves 4 - 6 m break, foam blows in streaks. | Whole trees move, awkward walking. |
| 8 | 34-40 |
55-64 |
Gale | Gale warning 34 - 47 knots. All boats head in. Tie up in very secure marinas or mooring. Clear decks of canvas, barbeques, flags. Remove small boats from marinas. Secure fingers and piers. | Moderate 4 - 6 m waves of greater length, foam blows in long streaks. | Small branches start to break. Walking is hard. Floating docks might be at risk. |
| 9 | 41-47 |
66-76 |
Strong Gale | Consider pulling boats onto dry land, particularly if fetch could be across open water. | High waves 6 m, rolling sea, dense streaks of foam, spray reduces visibility. | Buildings and piers show small damage. Some boat damage likely. |
| 10 | 48-55 |
77-86 |
Storm | Storm warning 48 - 63 knots. Pull boats onto dry land, particularly if fetch to marina could be across open water.**. | Very high waves 6 - 9 m m, overhanging crests, sea white with foam, visibility reduced. | Pier and boat damage will occur, trees uprooted. |
| 11 | 56-63 |
90-101 |
Violent storm | Definitely pull boats onto dry land, or set hurricane moorings. | Exceptionally high waves 9 - 14 m, sea covered with foam, visibility poor. | Extreme danger, widespread damage. |
| 12 | 64+ |
103+ |
Hurricane | Several 'force' categories of hurricane. | Waves tremendous, over 14 m, air filled with spray, sea white with foam, visibility nil. | Extreme danger, widespread damage. |
11 Nautical Mile is about 6,076 ft; 1 Knot = 1 NM/hr, or 1.852 km/hr.
21 km/hr = 0.540 NM/hr.
**Hurricane Juan winds peaked in Charlottetown at 50-55 knots (Force 10) from the south across the harbour (fetch 1 mile), causing extensive damage to boats and piers in both marinas. One boat recorded a peak gust of 72 knots, I think.
Beerfort Scale***
Force 0: Sails hanging limp. Tiller tends itself.
Force 1: Beginning pressure on sails. If sheet is eased out, the tiller still tends itself.
Force 2: Sails flapping in the breeze, and boat drifting to leeward. Sheets must be tightened and one hand put on the tiller. As the wind fills the sails, the boat heels. Case of beer must be placed on cockpit floor.
Force 3: The beer may be knocked over and must be supported or held in hand.
Force 4: Empty bottles rolling against each other on cockpit floor. Must be thrown over side.
Force 5: All beer streaming behind boat must be hauled in.
Force 6: Nobody can hold onto more than one beer at a time.
Force 7: The case of beer slides back and forth on cockpit floor. One person must be appointed to sit on it.
Force 8: Bottles can still be opened by one person. Beginning of difficulties pouring into the mouth without spilling.
Force 9: Bottle must be held with two hands. Only experts can get the cap off by themselves.
Force 10: Two people required to open bottles. Empties must be thrown to leeward only. Very difficult to find mouth. Some teeth may be knocked loose.
Force 11: The beer tends to foam out of bottle. Very difficult to drink. Lips split and teeth fall out.
Force 12: All open bottles foam. Impossible to drink. Temporary abstinence may be required.
***The Blue Heron Squadron reminds everyone that drinking while boating is dangerous and illegal. But a little laughter never hurt anybody.
