Weather (original) (raw)
Heavy weather is any weather condition that results in high winds, extreme sea states, and heavy rain, snow and/or hail. Obviously, weather of this type results in extremely uncomfortable conditions on board ship. Excessive rolls, yaws, pitches, coupled with taking on water make work and living dangerous. There are a multitude of hazards that occur in heavy weather. Objects can slide or fall on personnel, causing injury. Personnel can fall into machinery or equipment. Personnel working exposed to the weather can be washed overboard or against fixed objects. Heavy weather is as dangerous now as it was during the days of sail, and all personnel must be aware of potential hazards and safety requirements.
BEAUFORT SCALE
(NOW USED INSTEAD OF SEA STATE TABLES)
| NUMBER | DESCRIPTION | DEFINITION | WINDS (KTS) | AVG WAVE HEIGHT (FT) | SEA STATE EQUIVILANT (NOTE 1) |
|---|---|---|---|---|---|
| 1 | LIGHT AIRS | RIPPLES W/APPEARANCE OF SCALES. | 1-3 | 0.05 | 0 |
| 2 | LIGHT BREEZE | SMALL WAVELETS, GLASSY APPEARANCE. | 4-6 | 0.18 | 0-1 |
| 3 | GENTLE BREEZE | LARGE WAVELETS, CRESTS BEGIN TO BREAK. | 7-10 | 0.6-0.88 | 1-2 |
| 4 | MODERATE BREEZE | SMALL WAVES BECOMING LARGE WAVES, WHITE CAPS APPEAR. | 11-16 | 1.40-2.90 | 2-3 |
| 5 | FRESH BREEZE | MANY WHITE CAPS, CHANCE OF SEA SPRAY. | 17-21 | 3.80-5.00 | 3-4 |
| 6 | STRONG BREEZE | LARGE WAVES BEGIN TO FORM FOAM CRESTS EXTENSIVE PROBABLY SPRAY. | 22-27 | 6.40-9.60 | 4-5 |
| 7 | MODERATE GALE | SEA HEAPS UP, WHITE FOAM BLOWS IN STEAKS SPINDRIFT IS SEEN. | 28-33 | 11-16 | 5-6 |
| 8 | FRESH GALE | MODERATELY HIGH WAVES OF GREATER LENGTH. FOAM IS BLOWN SPARY AFFECTS VISIBILITY. | 34-40 | 19-28 | 6-7 |
| 9 | STRONG GALE | HIGH WAVES, DENSE FOAM STREAKS, SEA BEGINS TO ROLL. | 41-47 | 31-40 | 7-8 |
PIERSON-MOSKOWITZ SEA SPECTRUM
(BEING PHASED OUT IN FAVOR OF THE BEAUFORT SCALE)
| SEA STATE | SIGNIFICANT WAVE HEIGHT (FT) | SIGNIFICANT RANGE OF PERIODS (SEC) | PERIOD OF MAX ENERGY (SEC) | FREQUENCY MAX ENERGY (SEC) | AVERAGE PERIOD (SEC) | AVERAGE WAVE LENGTH (FT) | WIND SPEED (KTS) |
|---|---|---|---|---|---|---|---|
| 0 0 | 0.10 0.15 | 0.34-1.09 0.42-1.33 | 0.87 1.07 | 7.22 5.87 | 0.62 0.76 | 1.31 1.97 | 2.51 2.83 |
| 1 1 1 | 0.501.00 1.20 | 0.77-2.431.09-3.43 1.19-3.76 | 1.952.75 3.02 | 3.222.28 2.08 | 1.391.96 2.15 | 0.5713.14 15.76 | 5.177.31 8.01 |
| 222 2 | 1.502.002.50 3.00 | 1.34-4.211.54-4.861.72-5.43 1.89-5.95 | 3.383.904.36 4.78 | 1.861.611.44 1.31 | 2.402.773.10 3.40 | 19.7026.2732.84 39.41 | 5.0510.3411.36 12.66 |
| 3 3 3 3 | 3.504.004.50 5.00 | 2.04-6.432.18-6.872.31-7.29 2.44-7.68 | 5.165.525.86 6.17 | 1.221.141.07 1.02 | 3.673.924.16 4.38 | 45.9852.5459.11 65.68 | 13.6814.6215.51 16.35 |
| 44 4 | 6.007.00 7.50 | 2.67-8.412.89-9.09 2.99-9.41 | 6.767.30 7.56 | 0.930.86 0.83 | 4.805.19 5.37 | 78.8291.95 98.52 | 17.9119.34 20.02 |
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