Anchoring Made Easy
Article from United States Power Squadron
by LT/C Larry Golkin, AP SEO
Many boaters do not enjoy anchoring out for a variety of reasons. Some are afraid of dragging anchor. Others are scared of the dark ocean at night. Many boaters do not have sufficient ground tackle. Simply stated, the biggest reason boaters miss the opportunity to convene with nature in this way is that they do not know how to anchor a boat.
Anchoring is really simple if you have the proper equipment and certain bits of important information.
Select the Right Anchor
There are several different types of anchors. Nevertheless, there are certain very important attributes you should keep in mind when selecting an anchor. Will it set quickly, and hold in a variety of different bottom types? Can it withstand significant loads? Is it easy to deploy and retrieve, and is it easy to store?
An anchor is a significant piece of safety equipment. Look for quality construction features such as heavy-duty components, strong materials, strong welds, and quality galvanizing. You should have at least one heavy anchor for each type of bottom you expect to anchor on. Actually, you should have more than one depending on the bottom conditions, and you will need two (bow and stern) in tight anchorages.
There are essentially three categories of anchor. First, there are those with deep penetrating, lightweight, pivoting flukes such as the Danforth or the Fortress. These anchors are reported to have the greatest holding power per pound of any style of anchor. Second, there are the plow-style anchors such as the Bruce, Delta, CQR, Spade and Max. These have excellent structural strength, but do not penetrate as deeply into the seabed as fluke-style anchors. On the other hand, they tend to set more easily due to increased weight. Finally, there are specialty anchors for specific bottom types. Variations on all of these traditional designs exist, and new ones seem to pop up all the time.
No single anchor design is best in all conditions. Thus, a critical consideration when selecting an anchor will be the bottom conditions in the areas you want to visit. In fact, empirical studies suggest that the selection of a suitable bottom for anchoring is a much more critical factor than the design of the anchor.
Sand is relatively easy for anchors to penetrate. Most anchors will hold best in hard sand. The Danforth and Fortress anchors work very well in sand. Mud, on the other hand, has low sheer strength, and requires an anchor with a wider shank-fluke angle and greater fluke area so that the anchor will penetrate deep to where the mud has greater sheer strength. Mud is frequently thin and layered over some other material. Thus, anchors that can penetrate through the mud to the underlying material will hold better. Fortress anchors work very well in mud, because they can be converted to a broad fluke angle.
Rock and coral bottoms present different challenges. Here, holding power is more dependent on where you happen to drop the anchor, than on the type of anchor you have. Plow-shaped or grapnel-type anchors generally work best. These include the Bruce, CQR, Delta, or Yachtsman. Shale, clay and grassy bottoms present tough challenges for all anchor designs. Here, it is the weight of the anchor, more than its design, that is the most important factor. CQR, Delta anchors, and Yachtsman anchors are able to penetrate the vegetation. However, be careful of a "false-set" as it is possible the anchor has caught on roots or other protrusions rather than something solid.
Now that I have an anchor, what do I attach it to?
Anchor rode on pleasure boats generally consists of three strand nylon line with a short length of galvanized chain. Nylon is used because it stretches thus reducing the load on your anchor. Chain is used between the anchor and the nylon line for abrasion resistance, and to keep the pull on the anchor shank more parallel to the seabed. Experts recommend that the amount of chain be equal to at least one-half to one full boat length, and of a diameter equal to one half that of the nylon line. Some boaters prefer an all chain rode as it reduces the need for scope, and, due to its weight, it lies easily on the bottom.
Setting the Hook
The best anchorage offers a good holding bottom, suitable depth, and protection from wind, waves and passing craft. Setting your anchor properly is critical to holding your boat in place. Follow these steps to anchor your boat:
1. Select an area of little current, protected from the weather, preferably with a flat bottom. The area should be well upwind of where you want the boat to end up. Make your approach slowly into the wind or current. Look at other boats in the anchorage and follow their lead in using either a single anchor or bow-and-stern anchors. Determine where their anchors lie so you will not foul them, and select a position that will allow you to swing with the wind or current without bumping into other boats.
2. Prepare Your Crew. Nothing marks a novice as much as yelling orders at your crew, and a briefing beforehand will let your crew know what you expect of them, as well as help you to sort out the anchoring procedure in your own mind. Keep a pair of work gloves aboard to protect their hands from the rode and chain, as well as from mud or seaweed that may come up with the anchor.
3. Be Quiet. Because it is often hard to hear over wind and engine noise, I use hand signals to let my crew know what I want. To start lowering the anchor, I use a thumbs down signal. To stop paying out the rode, I clench my fist. For the crew to let me know the anchor rode is securely cleated, they clasp their hands above their head. To raise the anchor, I use a thumbs up.
4. Be Courteous. If you are not sure how a nearby boat is anchored or where their anchor lies, cruise past and ask them. It's much better to find out now, before you have to re-anchor in another location.
5. Don't Splash. Never throw the anchor over the bow: it is a sure way to both tangle your anchor and mark yourself as an amateur. And be sure that the boat has stopped all forward motion before lowering the anchor, or you could tangle your propeller.
6. When at the spot, stop the boat, and check that the boat will be free to swing in all directions. Slowly lower the anchor over the bow to the bottom, and then slowly back the boat away, downwind or down current.
7. Once the hook is on the seabed, put your engine in reverse until you feel the hook dig in. Back up steadily, paying out anchor rode until you reach the predetermined scope. Let out about seven to ten times as much line as the depth of the water, depending on the wind strength and wave size. Scope is the ratio of the amount of anchor line paid out to water depth plus freeboard. Anchors hold best when the pull on the anchor is parallel to the bottom. More line paid out also increases shock absorption by the anchor line. Anchoring experts recommend 7:1 scope when possible. Using a larger anchor or more chain to lower the angle of pull will compensate for shorter scope.
8. Tie off the line around a bow cleat, and pull on the anchor to make sure it is secure. After anchoring, check your position with local landmarks. While at anchor, recheck these landmarks periodically to make sure you aren't moving. Most GPS units have an alarm that will alert you if the boat moves. Be sure to use it if you are going to sleep aboard at anchor.
9. Periodically check connecting knots on your anchor line. When possible, use splices instead of knots. Knots weaken a line more than splices Remember, when anchoring overnight, you must turn on an anchor light. Also, never anchor or otherwise obstruct passage through channels or areas such as lauching ramps or any other high traffic areas.
Follow these guidelines when retrieving your anchor:
1. Always retrieve your anchor into the boat before leaving the area.
2. To retrieve the anchor, move the boat over the anchor while pulling in the line. Pulling the anchor straight up should break it free. If the anchor is stuck, turn your boat in a circle while under power.
3. When the anchor breaks loose, stop the boat, and retrieve the anchor. Never drag the anchor behind the boat.
A Few Extra Reminders
Wind determines the overall force on an anchoring system. Larger boats present greater resistance to wind, which in turn causes a heavier pull on the anchor and rode. Sizing anchors based upon conservative wind velocities is foolish because you cannot run out and buy the next size up when the wind starts blowing hard. It is recommended that you size your anchor to withstand heavy weather.
Make sure you inspect your entire anchor system frequently for chafe, loose shackles, and bent flukes. The system is only as reliable as its weakest component.
Store at least one anchor so that it can always be used immediately. Even the strongest anchor will not do you any good if you cannot deploy it. Quickly deploying even a small anchor can keep you from going aground.
Be aware that the boat will swing down wind or current from the anchor. Allow "swing room" for any change in wind or current!
Since anchoring can be an emergency procedure, store the anchor and its lines in an accessible area. Use the anchor immediately to avoid drifting aground if the engine breaks down.
Anchoring is one of the most important skills to master if you plan to cruise from one area to another. Since there is rarely any need to rush, use the same slow, cautious approach to anchoring that you use when docking. With a little preparation and practice, you'll be the one enjoying the pina colada in the cockpit watching others as they anchor.