How much line if you anchor in 20 feet of water?

How do you properly anchor a sailboat offshore?

You need to carefully choose a spot that is protected from wind and waves. Look for a smooth and even bottom, ideally no deeper than 15 feet. To properly anchor, you must first slowly lower the anchor, bow into the wind, engine idling. When the anchor hits the bottom, but before the attached chain begins to coil up, signal the helmsman to put the engine into reverse. Lay out the chain attached to the anchor onto the bottom, and then feed out about 7:1 line, which means a 15 foot depth, plus about a 4 foot height above the water requires about 133 feet of anchor rode (as the line attached to an anchor is known). When the rode is tight, stop the engine. Then make sure you don't drift! if you dont' have a motor.....then you'll need to do the same thing into the wind, and use the backed jib or main to lay out the rode. Much more difficult.