Most anchors hold well in mud and sand bottoms, but may not perform as well in rocky or weedy bottoms. This must be considered when selecting a boat’s anchor.
The figure above shows five types of commonly used anchors. The CQR (or Plough) anchors are good in most types of bottom, while the Danforth is good in sand and mud, but not in rocks or weeds. The Grapnel is fairly good in rocks and boulders. The Navy and Mushroom anchors are lightweight anchors easily used for a short stay. A secondary lighter anchor should also be carried on a boat, in case the main anchor is lost.
Selecting the anchorage
Anchoring is not as easy as it seems and a little practice will be a big help. Choose a well-protected area, preferably with a flat bottom. Approach slowly, upwind or against the current, whichever is the stronger. Check that the bitter end is indeed tied to the boat. When in position, stop the boat and lower the anchor slowly over the bow until it reaches the bottom. If anchoring overnight, allow room for the boat to swing as the wind and current may change. You need a larger anchor for overnight use and stormy weather. Lower, never throw the anchor over the side.
Setting the anchor
To set the anchor, run the boat slowly astern and let the anchor line run out until its length is about five to seven times the depth of the water plus the height of the bow above the water. The anchor line is then tied to a strong point on the boat’s bow. As the anchor sets the bow will turn into the wind and the anchor line will stop jerking. From time to time check to see that your anchor is holding, not dragging. Use two landmarks to pinpoint your position. If anchoring at night you must display an anchor light, a white light visible all around.
A small boat should never be anchored over the stern, or side, because it may be swamped by waves, or drawn under by a strong current.
To learn more about anchoring and boating techniques register for a CPS Boating Essentials Course near you.
Here are some video demonstrations of 11 different types of anchors and how to set them.