Anchoring Tips for Boaters
A Fluke or Danforth Anchor
How to Anchor a Boat is a Basic Boating Skill
How to anchor a boat is one of those things in a boater's life that seems simple. It can be, but it can also be a nightmare. Like most boating chores, anchoring requires that you follow some basic rules. If you follow the steps your boat will be held firmly in place. Ignore the steps and you can find yourself adrift—and possibly in danger. This article is about anchors and anchoring a powerboat, which also pertains to a sailboat under power. Sailboats use the same kind of anchors as powerboats.
The type of anchors that you use depends on the characteristics of the bottom. The most common type of anchor for typical sandy bottoms are fluke or Danforth anchors. This is the most common type of anchors used on modest sized pleasure craft. You should have more than one anchor aboard. Three anchors is a good rule of thumb, depending on the size of your boat. But even for a small boat, at least two anchors is recommended in case you lose one.
How to Anchor a Boat — The Basic Steps
1. Some useful terminology:
· Anchor rode. This is the chain or rope that attaches to the anchor. Some boaters use a combination of chain and rope, that's why the one word "rode" is what you should use, even if you have only rope or chain. Besides, it sounds salty. Typically an anchor rode will be made of rope with a few feet of chain attaching it to the anchor. A 3/8 inch diameter rope is most common. How much rode should you have aboard? A good rule of thumb is to estimate the deepest water you expect to anchor in and multiply it by 8. The authoritative boating book Chapman Piloting and Seamanship recommends that for boats from 15 to 35 feet in length, you should have 150 feet of anchor rode aboard, 180 for boats 26-30 feet, 200 for 31 t0 35, 250 for 36-40 and 300 for 41-60.
· Scope is the ratio of the length of the anchor rode to the height of the bow above the bottom. The greater the scope the more horizontal pull it will exert on the anchor, and the better it will hold. The strongest scope is a ratio of 10:1,because it provides a holding power of 100 percent. If your bow is 10 feet off the bottom and you want a 10:1 scope, you will let out 100 feet of rode; 20 feet and you need to let out 200 feet of rode.
2. Mark you anchor rode. You won't know how much rode to pay out unless you can see or feel a marking to let you know how much you have already let out. Chapman recommends five or six marks at intervals of 20 feet from about 60 to 140 feet. Some boaters paint markings at the intervals, while others prefer fabric or leather markers to enable them to feel the anchor line markers in the dark.
3. Check your depth. This may seem obvious, but you should not drop your anchor in water that is deeper than the amount of anchor rode you have on the boat. Be sure to refer to a chart and calculate the depth at high tide. If, for example, the tide in your anchorage has a 10 foot range, this means that your anchor scope will be significantly shorter at high tide if you anchored at low tide.
4. Head into the wind. This will ensure that the boat won't be swinging as you or your crew member drops the anchor.
5. Back slowly until you have let out enough anchor rode to give you the scope that you want. As the drawing illustrates, how much scope you want depends on how long you will be anchored as well as weather and sea conditions. If it's just for a brief time and the weather is calm, you don't need to let out as much rode as you would if you're planning an overnight stay.
6. Check your anchor's grip. Once you have determined that you have the scope you want, make sure that the anchor is firmly imbedded into the bottom. You do this by using a simple nautical range. Pick a fixed object on the boat such as a stanchion and line it up with a fixed object ashore. If you see the stanchion start to move behind the object ashore, your anchor is dragging.
How to anchor a boat isn't rocket science, but by obeying the above rules you will avoid the embarrassment (and danger) of finding yourself in a different place from where you anchored.