From "Circumnavigating the Delmarva Peninsula - A Guide for the Shoal Draft Sailor", by permission:
This is rather long, but there is some good information here, specific to the area and lighter anchors and lighter boats, some of it non-traditional, but all well proven.
Anchoring. Secure overnight anchoring is central to successful cruising, and tales of misadventure abound. Dragging can certainly cause damage to your boat and others, or result in serious grounding. Lack of sleep, pondering whether your mooring is secure, will detract from your enjoyment of the trip and contribute to poor decision-making. A good night sleep may be the largest single safety requirement for the crew. Finally, rates in resort area marinas are ridiculous, and building a sound mooring will allow you to leave your boat for free while you explore.
• Holding ground. Hard clay, oyster shell, and occasionally very soft mud, silt, or heavy weed are unsuitable. There may be no anchor type that can penetrate or hold, or the penetration and holding may be unreliable or difficult to gauge. If possible move to firm sand or sticky mud. No anchoring system can ever be better than the medium at the bottom.
Good advice. I'd also recommend sand, but that's pretty scarce in the Chesapeake.
• Anchor type. Danforth pattern anchors are by far the most popular, and for good reason. They are light, cheap, and powerful in sand and mud. I carry a 13-pound and an 8-pound Danforth type. The aluminum Fortress designs are excellent, but I have found them less than effective in hard clay or shell. A dumb, heavy Danforth imitation can work just as well, since breaking strength isn't at issue for smaller boats, while the ability to sink through soft mud and silt or bite hard clay often is.
Bad advice IMHO. Danforths are lousy anchors for overnight use—especially if the wind or current reverse.
Sharpening the flukes with a grinder and removing excess flange material near the tips can also help anchors bite into hard bottoms or cut through vegetation.
Again, bad advice IMHO, since grinding the edges of the flukes also removes the galvanization—which will allow corrosion to quickly eat away at the steel of the anchor.
Attention to detail is why genuine Danforth and Fortress anchors bite so predictably. Because Danforth style anchors are close to useless on oyster shell, rock, or very hard mud, I carry a 12-pound Northill, though a Delta or other hooking/digging anchor would certainly do as well.
A northhill, which looks like this:
is a lousy anchor in oyster shell, rock or very hard mud, unless it is very large. It doesn't bite all that well or hold well, and is primarily dependent on its mass to keep it in place. Also, if the current or winds reverse, you stand a good chance of fouling the unburied fluke with the rode and pulling the anchor free with no chance of it resetting.
It is important to understand the character of the anchor you are using: a Danforth in a good bottom will stand a straight pull until it breaks... unless the direction of pull changes more than 90 degrees, whereupon it will lift out and probably not reset; a plow-type will reset and vear, but it will also drag through soft mud when the force becomes very great, so they cannot be even a little too small and some shifting or dragging in a powerful squall is to be expected and planned for. A Danforth requires only a little chain, the plow-type requires a good length of chain for its reset properties to function. Neither is better - they are two different things. Plow-types are handy on a big boat with a winch and bow roller to handle the mass or anchor and chain, fluke types are common small boats where the anchor must be handled manually.
The next generation anchors, like the Rocna, Spade, Manson Supreme, etc., are far less likely to move through soft mud, having either flat or concave blade faces—causing the mud to pile up in front of them rather than pushing it to either side. They're generally far better than plow-type or fluke-type anchors in performance, especially if the winds/currents reverse or shift.
• Rode. Three 150-foot nylon rodes are required, doubled braid being best as it will not hockle in use, with five feet of chain or cable at the anchor end for abrasion resistance. I use retired rock climbing ropes, which perform better than any anchor rope made; they are carefully engineered to resist abrasion, absorb impact, and handle easily. These can easily be obtained for a song either on e-Bay or at the local climbing practice area. They are pampered, carefully monitored, and retired after a few seasons, only just broken in. Mark the rode at regular intervals; mine is marked every 30 feet (5 fathoms) with cable ties. This will allow you to correctly measure scope and gauge the arraignment of multiple anchors.
Octo-plait is much better than double braided lines or three-strand for use as anchor lines. Double braid is also less elastic than either three-strand or octo-plait. Double-braid is impossible to properly splice to chain and requires the use of a thimble. This becomes a serious problem if you use a chain/rope anchor gypsy on your windlass, since the thimble will cause the rode to jump out of the gypsy. Using retired line of any type is just stupid and foolhardy IMHO. You don't know what condition the line is in internally or what kind of strains it was exposed to—meaning that you're depending on a relatively unknown quantity for your security.
• Remember the tide. I'm so used to the nonexistent tides of the middle and upper Chesapeake Bay that I easily forget that the water goes down 4-5 feet near the ocean. Allow for a minimum 7:1 scope a high tide; however, in shallow, un-crowded anchorages with strong currents, there is no reason to use less than 10:1 scope.
Calculate your scope based on the high-tide depth plus height of the bow roller off the water. If you're anchored in 10' of water at low tide, with a tidal range of 5' and your bow roller is 3' off the water, for a 7:1 scope, you need 126' (70+35+21) or so of rode out—not the 70' you'd think due to the 10' depth you're currently in. 10:1 scope is pretty much unnecessary, unless you're expecting storm conditions. BTW, anything beyond 8:1 does very little to add any real benefit.
• Two anchors for wind and current shift. It is important to understand is that multiple anchors do not always increase the holding power of your mooring versus a single anchor. Certainly two anchors placed side by side can provide improved holding in a poor bottom, but only if the wind remains in a constant direction, and with Chesapeake Bay thunderstorms that is unlikely. If the anchors are set at an angle of between 0-90° to each other, even a modest change in wind or current will swing the boat far enough to one side to place the entire strain on one anchor. If the anchors are set at an angle of 90-180° to each other, the load on each anchor is greater in a crosswind than if there were only a single anchor—potentially many times greater; consider the considerable leverage a tight-rope applies. Thus, a protected anchorage is still required. However, well separated anchors do maintain the angle of pull on each anchor in a consistent and controlled range of directions. A compromise is required. My typical anchoring method in 10 feet of water: lower the first anchor and pay out 100 feet of rode while backing down, lower the second anchor and pay out 70 feet of rode while backing toward the first anchor, simultaneously take in the first rode to about 70 feet, just sufficiently to prevent propeller fouling. This is neither a bahamian moor nor lying to open-hawse, but is more appropriate to the tides and thunderstorms of the Chesapeake Bay and barrier islands. A properly sized light weight anchor with adequate scope is exceptionally strong when well buried in a good bottom—that is, anything but very soft mud—it should not pull out in any protected anchorage in any squall. At the same time, we know a danforth is weak when pulled 90° off-line, and virtually useless if the direction is reversed 180°. A light breeze will remove it, and with any sort of sticky Chesapeake mud or oyster shells clogging the flukes, there is very little chance of resetting. Setting two anchors at a 90 degree angle ensures that the anchor pull will remain within 45° of the setting direction.
You're far better off with the simplicity of using a single, properly sized anchor, rather than two smaller anchors. If your boat veers and the anchors are not properly sized to hold it, it may pull one free and then when it swings back, all the load will be on the remaining one... A properly sized single anchor is simpler to launch, retrieve and use. Using multiple anchors on a regular basis says much about your ground tackle being improperly sized to begin with.
• Three anchors make a mooring. With three anchors the pull will be within 20° of the initial setting direction. The following general procedure can be used in 10 feet of water: lower the first anchor and back down 100 feet, lower the second anchor and back down 100 feet at 60 degrees to the first course (at this point both lines will come tight), lower the third anchor along with 70 feet of rode, while pulling the other lines into about 60 feet. All three lines should be tight. Ease all lines to 70 feet and back down on each anchor as needed. My anchoring practices evolved from my mountaineering background; the American Mountain Guide Association teaches that every climbing belay anchor should be SERENE. Solid-Every part. Redundant. Equalized. No Extension should one element fail. An additional requirement, unstated but implied by the first requirement, is that the direction of pull on each anchoring element does not change in the event of a fall. Rock climbing anchors, though capable of holding up to 5000 pounds in the intended direction, can be removed with fingers alone when lifted in a counter direction. So it is with light weight boat anchors; they hold a strong pull in one direction, but cannot be relied upon to withstand a veer or reset if the direction of pull changes. It takes three anchors to fully meet the intent of this requirement, and that’s what I need to leave the boat for an extended period and remain relaxed. There is significant experience indicating boats weather hurricanes just as well lying to a triangle of three Danforth (large) anchors as to concrete moorings. Perhaps the consequences of a failed mooring are less mortal than those of a failed climbing anchor high on a massive cliff, but the basic principles are the same.
Again, the use of multiple anchors for anything less than a semi-permanent mooring, means that your ground tackle is woefully inadequate.
• Bridal for multi-hulls. Anchored by one hull, catamarans often sail about so furiously as to jerk the anchor out, or at best make for a restless place to sleep, and yet sit perfectly still when rigged using a bridal. Measure the bridal legs to create 30-degree angle at the apex. Keeping the centerboard down and the rudders up further reduces motion.
Bridles are good for most boats that have a tendency to swing at anchor. Bridals are only good if you're planning to get married.
• Keel wrap. When multiple anchors are laid without enough slack for the unloaded (leeward) rode to lie on the bottom, the keel, rudder, and prop can foul on the leeward rode when the wind or tide shift and the boat spins. In a protected anchorage with minimal currents, proper slack will avoid this; the unloaded rode will lie safely on the bottom. The loaded rode or rodes stay safely in front of the boat, away from the keel. However, if an opposing tide and wind is probable, a 10- to 20-pound sentinel weight 10-15 feet down will keep the rode away from the keel. It is simply impossible to predict where the current will blow the rodes while the wind pushes the boat according to its own whim. The following anchoring method is typical in 10 feet of water: lower the first anchor and pay out 100 feet of rode while backing down, lower the second anchor and pay out 70 feet of rode while backing toward the first anchor, simultaneously take in the first rode to about 70 feet, just sufficiently to prevent propeller fouling.
A sentinel will help prevent keel wrap. On boats with centerboards or swing keels, retract them completely when at anchor. If not, you may end up snapping them off when they get wrapped by the anchor rode.
Anchor Available on Deck. An anchor and rode must be accessible within 30 seconds when near shore. Three times, while single-handing, I have experienced engine failures in harbor areas, and having the hook immediately available made each into a minor incident. One was within 50 feet of a rock jetty, with a 30-knot breeze blowing at an angle. Boy, did that anchor look pretty.
Good advice. An anchor is an important bit of safety gear. Dropping anchor can often give you the time to deal with a problem safely, without rushing. A good idea is to have an anchor available at short notice in the cockpit. This can be especially important when transiting rivers or other areas with relatively strong currents.
Just curious, but is the book, "Circumnavigating the Delmarva Peninsula - A Guide for the Shoal Draft Sailor"
, that your quote is out of written by you or someone you know??? I've noticed you seem to be pushing the book fairly heavily in the Delmarva 2009 thread and was curious. If you do have a relationship with the book's author, that should probably be disclosed per the full disclosure policy of the forum here.