Published: Thursday, June 8, 2017 4:00 pm
Whether it be to stay put in that perfect cove for a lunch aboard, sleep overnight on the hook, keep a disabled boat from washing aground, or simply to keep anglers aboard within easy casting range of a productive fishing spot, it’s important you have the equipment and know-how necessary to securely anchor your boat in place. In fact, the ability to properly anchor a boat in an emergency situation is important enough that most states require adequate equipment be aboard all recreational watercraft. Any boater who has faced a situation when the ability to anchor their craft meant the difference between a momentary distraction and an all-out disaster understands why.
How Anchors Work
Anchors use a combination of weight and shape to hold the boat to which they are attached in position. The best combination of both features for a particular anchoring situation depends upon the composition of the bottom, be it mud, sand, rock, wood, grass or gravel.
The most popular anchor style for Great Lakes pleasure and fishing craft is the Danforth, or “fluked” type, which has a high holding-power-to-weight ratio. These relatively lightweight anchors rest flat on the bottom until tension from the anchor line forces the flukes downward, where they dig into the bottom. The broad stock at the crown prevents the anchor from flipping over and dragging.
The Danforth’s holding power in a variety of bottom types, including mud, sand, and clay is good. However, over grass- or rock-covered bottoms, the flukes may skip over the bottom or collect weeds or mud, preventing them from digging into the bottom for a firm hold even with the proper amount of scope. In those conditions, you need to weigh anchor and either stow the Danforth and try another type or move the boat to better bottom and give the Danforth anchor another try.
There are alternative fluke-type anchors that bury themselves in use, such as Plow and Bruce styles, and can hold better over sand, grass, or even rock bottoms, but they are more expensive and cumbersome to stow. Mushroom anchors are a third popular anchor type for smaller craft, and rely much more on sheer weight than their design to hold the boat in place, and are only useful in conditions of lighter wind and current.
Several non-traditional style anchors on the market are popular among boaters. The Richter Anchor relies on a combination of weight and a grapnel design to catch and hold bottom. The combo of the Richter allows it to be used with or without a chain, and the unique retrieving bar allows the angle of pull on the anchor to be changed to easily free it in the event the anchor becomes snagged on the bottom. Richter anchors come in weights of 18 pounds designed for boats up to 18 feet, and 25 pounds for boats up to about 25 feet, depending on conditions. The Richter’s mushroom-like design also allows them to be used with many anchor winches.
The Box Anchor from Slide Anchor is another alternative that requires no chain or high scope ratio, and holds well in most bottom conditions. The Box Anchor folds for easy stowing and is good for holding boats from 17 to 30 feet in length. It, too, has a quick-release feature, using the shank that rolls backward to pull the anchor loose from behind.
Most anchors must be “set” to be effective. Setting involves digging the anchor into the bottom to offer its full holding power. Power-setting is recommended with traditional anchors like the Danforth, although you can sometimes set an anchor manually or by using the current, wind, or boat drift to force the anchor into the bottom. To power set, you drop the anchor off the bow until it hits the bottom, making sure it does not foul on the rope or “rode” as it descends. Once the anchor is on the bottom, you put the boat into slow reverse, carefully paying out the amount of line to reach the proper “scope” or angle from the boat to the anchor. Snub the line around a cleat or bit at that point and when the line comes taut, the anchor should bite into the bottom. If it holds with the engine in reverse gear just above idle speed, the anchor is set.
The key to setting a Danforth-style anchor — and most other types — is the angle of the upward pressure from the boat. The lower the angle, the more apt the anchor is to dig-in, rather than lift off, the bottom. That’s why a long “scope” or line-length to the anchor is important. The standard scope recommended by most experts is 7:1, a length of anchor line equal to seven times the depth of water being anchored over. If you are attempting to anchor in ten feet of water, for example, you’d need 70 feet of “scope” or line leading from your bow cleat to the anchor chain. Several feet of chain are used between the anchor line and the Danforth-style anchor to weigh-down the shank to keep its angle low. The chain can also thwart abrasion when anchoring around rocks or other debris that could sever the plain anchor line.
The amount of scope actually needed to keep a boat in place varies greatly with the anchor type, wind, and water conditions. In conditions of little wind or current, less scope may be required, but to play it safe, the 7:1 ratio should be adhered to whenever possible when using a fluke- or Danforth-style anchor.
Two anchors can be better than one in certain situations. If you are anchoring out for the night, for example, and wind is a concern, you can set out a pair of anchors to increase your odds of staying put. The key to dual-anchor sets is placing each anchor at a different angle off your boat’s bow, to a maximum of 45 degrees between them. A proper two-anchor set will also reduce yawing and pitching due to wind, waves, and current, making for a much more comfortable anchorage.
In protected waters, you can use an anchor off the stern as well as the bow, to keep from swinging in the breeze or to keep it parallel to the shore or structure. Anglers often use bow and stern anchors to keep their boat broadside to the best fishing area, which allows the maximum number of anglers aboard to have easy access to the spot.
When in doubt while anchoring, increase your scope by letting out more line and set a second anchor for added security if you intend to stay in one spot for awhile, perhaps for a night aboard. If your boat has a GPS, you can check for anchor slippage by using the function available on most units to detect movement while at anchor. Unnerving as it may be in the middle of the night, the sound of a GPS alarm beats the alternative wake-up call of gelcoat on rock.