Always carry an anchor on board. You might think you'll never use it, and then you run out of gas with wind pushing you toward a rock jetty — that anchor will be your rescue tool.
On this day you just want a change of scenery, and decide to anchor in a quiet cove. But there's a breeze, strong enough to eventually push you into half-submerged timber. Your anchor should have at least six to eight feet of chain attached to it, with your anchor line attached to that. The chain will fall to the bottom near the anchor, giving it holding power.
Scope is the length of anchor line you should have out in ratio to the depth of water and height of the deck. Ideally the ratio should be 8:1 (in 10 feet of water you should have 80 feet of anchor line out). The closer the ratio (5:1, 3:1, etc.) the more prone the anchor is to pull out.
Don't hold the chain when throwing out the anchor. The chain or line can catch on a finger — yeeow!