 |
|
 |
Winds and Tides : Winds Winds Generally, fair weather brings a westerly and poor weather brings an easterly. The wind rarely blows out of the north and typically out of the south when it is in a transitional state from poor to fair weather.
This is the most hoped for wind and tends to be the most common wind in the summer months. During periods of fine weather the Fraser River valley encourages the production of thermal winds. This thermal breeze fills in the late morning at around 11 am. It will consistently increase until it hits its maximum for the day at around 2:30 pm. As it fills, it tends to bend onto the south shore. Later in the day, after thermal heating, it will blow more directly down the bay (Figure 2). This will reflect in the windward (heading west) leg of a race course by a persistent geographical back (shift to the left). The amount of this back from the leeward to the windward mark can be in the order of 10-15 degrees. As the wind builds there may be temporary oscillating shifts but once filled in, the direction seems relatively stable. Because of this; there are few to no 'passing lanes' so remember that starts and boat speed are at a major premium in a westerly. Typical wind speeds between 6-12 knots rarely rising over 20 knots. 
EasterlyEasterlies are the result of a depression or bad weather and are often accompanied by rain. The water is smooth and the wind will vary from quite light up to 20 knots. It is much more shifty as you will find both geographic and oscillating shifts often appearing in a layered effect. There are two dominant indicators to keep eye out for (Figure 3). If it is dark and raining to the left (north) side of the course, the wind will typically back (shift left). If there is a lightening low in the sky on the right (south) side of the course, then it is signalling the passage of a front. Watch out for a major veer (shift right) of up to 90 degrees. These shifts are from the median wind blowing out of the Bay. Typically a geographic shift to the left on the left hand side of the course occurs, particularly in bad weather, which favours the left hand side of the beat. Be careful; however, the sky lightening low in the south may signify a large veer in the right hand side of the course as the front passes. Both of those wind shifts, while they are substantially geographic, may also show up as oscillating shifts. If heading north, don't forget to tack on the oscillating shifts! The key is to be able to respond to the overlay of the two shifts which may occur at the same time. Sailing in an easterly can be both challenging and rewarding racing. If you read the shifts right there are many opportunities to pass other boats. SoutherlyThis breeze will rarely last longer than 3-4 hours and typically arises when the weather is changing from poor to fair. There will be a significant temporal veer (shift right over time). While the wind is veering, there will be lots of unpredictable oscillations through a range of 90 degrees (45 degrees either side of median). In a southerly "You're on your own!"...Good Luck!
|
|
Westerly|
© 2002 - 2008 Royal Vancouver Yacht Club |