| Sailing Theory The sum of all wind pressure on the sail | | | | Weather- The Sea Breeze |
| is called wind force. The center of that force, which is | | | | As a sailor you should know about local winds. The |
| above the water, is called the center of effort (CE). | | | | cause of these winds is difference in temperature; cold |
| The center of the force below the surface of the | | | | air is heavier than warm air. The most popular of these |
| water is called the center of lateral resistance (CLR). | | | | local winds is the seabreeze. Warm air over the land |
| This is the point where all the boat's resistance to | | | | rises...And is replaced by cooler air sinking over the |
| sideways pressure is concentrated. | | | | ocean. At night the opposite happens. The land quickly |
| A boat performs best when the two forces are in | | | | loses its heat at night and oftenfalls to a |
| balance. This is when they are positioned one over the | | | | lowertemperature than the water. This results in a light |
| other in a vertical line through theboat's sail and hull. | | | | offshore evening wind. On a lake or river, the warm air |
| Your job as a sailor is to keep these two forces in | | | | can rise at the edges to be replaced by the cool air |
| proper balance so that your boat will sail correctly. You | | | | over the water. This can result in a nice breeze for |
| keep the boat balanced by shifting your weight and | | | | sailing. |
| adjusting your sail. | | | | Forcast for a Typical Sea Breeze Day: Morning Very |
| Your boat has weather helm when you have to | | | | Light Winds -No Weather Systems Near -Clear Sky |
| constantly pull the tiller towards you to keep the boat | | | | -High Temperatures But Cooler Near the Shore |
| straight on course. Lee helm is when you do the | | | | Afternoon: Wind coming from water starting Midday |
| opposite; pushing the tiller towards thesail. Most boats | | | | -Cumulus Clouds over land -Clear over water- Winds |
| are designed to have a little weather helm. However, | | | | Speeds 8 - 12 knots Evening: Winds Decreasing as |
| too much of it can make sailing difficult in anything | | | | sun slips over horizon. |
| other than light breezes. If your boat has a lot of | | | | Sailing Terms |
| weather helm, it means the CE and the CLR are not in | | | | Amidships- the middle of the boat. |
| alignment. There is more sail pressure aft of the CLR | | | | Backwind- the wind flowing off the sail. |
| than forward of it. | | | | Close Hauled- one of the points of sail; sailing as close |
| To correct the balance, 1. Shift your weight aft (back | | | | to the wind as possible. |
| towards the stern). 2. Pull up the centerboard. 3. If your | | | | Dead Astern- straight behind |
| boat has a jib, ease (let out) the mainsail. 4. Try any | | | | Flaking- Folding the sail. |
| combination ofthese. | | | | |