Anchoring 201

Sometimes, simply figuring out scope and dropping the hook aren’t enough.

At some point all boaters encounter conditions where the basic anchoring techniques they’ve used successfully hundreds of times before just aren’t cutting it.
An anchor that won’t stop dragging no matter how many times it’s reset (or won’t let go when it’s time to leave), an otherwise perfect anchorage with limited swing room, anchoring in shifting current and winds — all are problems that can be addressed by knowing the proper techniques and when to employ them.

Techniques

Current Change

Want to drop the hook in an area that experiences 180-degree current shifts but have concerns a standard single-anchor setup just can’t deal with it? Try the Bahamian moor, an anchoring technique that gets its name from the contrary winds and tidal currents found in that region. Deploy one anchor upstream and a second one downstream, with both rodes attached at the bow, which allows the boat to ride between the two. As the boat swings 180 degrees during current shifts, the first and second anchors alternate between being the riding anchor (the one upstream under tension) and the lee anchor (the one down current with no load), and the boat is always pointing bow up. The Bahamian moor not only provides a secure way to anchor in areas with reversing currents but can also be used to limit a vessel’s swing radius in other situations.

The Bahamian moor has its downsides. One is the possibility of twisted rodes, a result of vessel swings or circles during current shifts. Another is the potential chafing of combination rope-and-chain rodes if the slack rode rubs against the vessel’s hull or snags on the keel or running gear, which could prevent the vessel from swinging to its new position with each current change. The latter can be prevented by bridling or attaching the rodes together at deck level, then lowering them until they reach below the keel. When one of the rodes is all chain, the chain’s weight is normally enough to accomplish this, but you may need a kellet if you use two combination rodes. (More on kellets later.)

Current Change

Current Change

Wind Shifts

If the problem is shifting winds rather than contrary currents, give dual-anchor mooring a try. Set two anchors to windward, 45 to 60 degrees apart, so the rodes form a V with the boat centered in its apex. The simplest way to accomplish this in light winds is to let go the first anchor, motor at a right angle across the wind the intended length of the first anchor rode and then release the second anchor, adjusting the rodes as needed afterward while falling back between the two. In strong winds, set the first anchor as you would normally (with the length of rode you need) and then motor upwind at a 45-degree angle. Drop the second anchor when the boat is abreast of the first and then fall back between the two, again adjusting the rodes as necessary.

Be sure to monitor rode locations during both procedures — specifically combination rodes — to avoid sucking them into your prop. Using marking buoys will make it a lot easier to keep track of anchor positioning during all this. While deploying matching rodes (either combination or all chain) for both anchors makes it easier to correctly position the boat, rode types can be mixed if necessary — just increase the scope of the combination rode to match the holding power of an all-chain rode.

An added benefit of dual-anchor mooring is the option of paying out additional rode as the wind pipes up. Doing so reduces the angle between the two anchors and increases their holding power. Thirty-five degrees is considered optimal in gale conditions. Placing the largest anchor in the direction of the strongest expected winds will also improve holding power.

Wind Shifts

Wind Shifts

 

Crowded Anchorage

So you get underway later than planned and arrive at the anchorage to find it’s standing room only. There’s one slice of water left that’s doable — if you can limit the boat’s swing radius. Or, you find that perfect gunkhole with deep water right in the middle, but there’s no room for swinging without bumping into a shoal. One possible solution for both cases is fore-and-aft mooring.

Setting the anchors for fore-and-aft mooring is similar to Bahamian mooring, except the rodes are located at bow and stern, one each, rather than the bow alone. The trick to fore-and-aft mooring is visualizing where the boat should end up once both anchors are out and setting them accordingly. For example, if you want 100 foot of rode out, drop the bow anchor that distance forward of the spot you’ve chosen, back down 200 feet and drop the second anchor. Next, take in 100 feet of the bow anchor rode while letting out the same amount rode for the second, or aft, anchor. Finally, snub up both anchors at the bow and stern and center the boat between the two. If both anchors are located at the bow, simply lead the rode for the second anchor aft to a suitably strong cleat or other such attachment point. Having both anchors ready in advance and briefing the crew, so all members know their role, before anchoring will make deployment smoother.

There are disadvantages to fore-and-aft anchoring, however. While it makes more efficient use of available anchorage space, everyone needs to do it, or boats may bump into each other if there’s a wind or current shift. It’s also not recommended if there are significant crosswinds or currents, both of which can place high side-loads and unwanted strain on boats’ ground tackle.

Crowded Anchorage

Crowded Anchorage

Bag of Tricks

At Ease at Anchor

There are additional tricks to improve a boat’s performance on the hook that have nothing to do with the hook itself. One trick is to use a kellet — also known as an angel or sentinel — which is simply a weight sent down the rode once the anchor is set. The kellet steepens the rode’s entry angle and decreases the anchor’s lead angle on the bottom. A kellet can be useful in many situations, such as when an anchor is dragging in a location where the anchorage is too deep or crowded to make paying out more rode a viable solution.

A kellet should weigh between 25 and 35 pounds for a typical 35-foot vessel, but this can be increased in severe weather to generate additional holding power. Ideally, the kellet should be positioned roughly halfway along the rode between the bow and the anchor, but this can be varied to compensate for local conditions. For example, placing it farther up increases the shock-absorbing qualities of your rig, while lowering it closer to the anchor increases holding power. The kellet retrieval line should be attached to a bow deck cleat and kept fairly taut, to reduce chances of fouling.

Kellets can be purchased or made from materials at hand, such as scuba-diving weights, a weighted canvas bag or even a small anchor. They can also be constructed from a 1- to 2-foot section of large-diameter PVC pipe capped at both ends and filled with lead or chain. A large shackle can be used as a rider for the kellet on all-chain rode, but if you have a combination rode, use a saddle rider, a snatch block or another suitable means of attaching the kellet, to prevent chafing the rode.

Another common problem for boats on the hook is “anchor sailing” or sheering, which is caused by windage from a boat’s hull, superstructure and rigging. With each wind shift, the bow falls off, only to be brought up short by the anchor rode, which in turn forces it to point in the opposite direction. Sheering is more pronounced in modern boats with wide beams and narrow keels, but any vessel riding to a single anchor is susceptible. Sheering is not only annoying but potentially dangerous due to the excessive side loads it places on ground tackle, which could lead to dragging or failure.

Using twin bridles or simply forming a bridle by attaching a second length of rope via a rolling hitch will reduce or eliminate sheering in lighter winds; however, in windier conditions the addition of an anchor riding sail is an excellent strategy.

A kellet weighing between 25 and 35 pounds will help lessen the rode in crowded anchorages.

A kellet weighing between 25 and 35 pounds will help lessen the rode in crowded anchorages.

Fouled Anchors

We try so hard to get our anchors to set quickly and hold fast, but it’s only a matter of time before we’re faced with the opposite problem — the anchor that won’t break free. Probably the easiest thing to try first is using the vessel’s own buoyancy and whatever wave action there is to help out. Position the boat so the rode is vertical, then snub it up as tight as you can with each successive dip of the bow, letting the pumping action of the vessel work the anchor free.

If this doesn’t work, let out a little scope (2:1) and motor forward in an effort to back the hook out. Circling the anchor while keeping the rode tight may work as well.

The above tricks will put your anchor on deck 95 percent of the time, but at some point you’ll drop the hook and Davy Jones just won’t let go (and I’m not talking about that guy from the Monkees). What you do then will be based on circumstances and what you have in your bag of tricks.

Anchor Retrieval

Anchor Retrieval Anchor Retrieval

If the water’s clear and the weather nice, grab a snorkel or diving gear and check things out. If that’s not an option, take a look at the chart for the anchorage and try to figure out what the anchor could be hung on — rocks, cable, etc. — and take appropriate action. If you think a cable or old anchor chain is the culprit, utilizing an anchor rider or chaser may do the trick. Shackle a short length of chain together to form a loop around the anchor rode, then lower it down to the anchor using a messenger line of double-braided nylon (3/8-inch minimum). Double-braided line has less stretch than three-strand and won’t snap back if it breaks or when the anchor comes free. Once you’ve worked the chaser over the anchor’s shank — keeping the rode tight and vertical will make this easier — use the messenger to pull the anchor backwards and, hopefully, free from the obstruction.

In extreme cases, you may have to buoy the rode, cast it off, and try backing out the anchor with the messenger by pulling 180 degrees from where you were originally anchored. You can also try fishing for the troublesome chain or cable with a grapnel, but be sure to attach a trip line to the grapnel’s crown to aid in retrieval in case it gets stuck too!

On the web

FortressAnchors.com
Lewmar.com (Delta, CQR)
Manson-Marine.co.nz
RhodanMarine.com
Rocna.com
WestMarine.com

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