Tides and currents effect us on every charter in one way or another. We will be most concerned with currents since the only times we are concerned with tides is when we plan on docking at another location. Currents are the horizontal movement of water in and out of the bay. Like a boat, the current has a direction and speed. Sailing on water is a little like walking on a conveyor belt: If you walk in the same direction as the moving belt, you will move faster, and if you walk against the moving belt you will walk slower.
The direction of a current is described as a flood or an ebb. A flood current means that the water is coming from the ocean into the bay. An ebb is the opposite, the water is flowing out of the bay and into the ocean. These are the only two directions of the current. There is a time when the current stops all together. This time is called slack, when the current is neither one way or another.
The other aspect of current is speed. Some days, the speed is extremely high and effects our boats a great deal, and other times it is very nominal and does little to effect us one way or another.
Every boat is capable of a calculated maximum speed. This speed is called the "Hull Speed". It is the maximum possible speed any particular boat is able to travel in still waters. A boat can travel faster than its hull speed only when it is traveling in the same direction as a current. Its maximum speed then becomes the addition of its hull speed and the speed of the current.
When sailing against a current, a boat can never reach hull speed. The maximum speed in this case is the hull speed minus the current's speed. If the current is as fast as the maximum boat speed, a boat can not go anywhere. If it is faster, the boat will actually sail in the direction of the current instead of forward.
