PS Advisor March 2019 Issue

Selecting a Stern Anchor

Photo by Ralph Naranjo (above)

This claw anchor is designed to quickly deploy from a pivoting roller on the stern of a boat based in Europe, where bow-to Med-mooring is common.

I have a 30-foot sailboat and I was considering keeping an emergency anchor ready to lower quickly as a temporary way to stop drifting in case the engine failed. I have limited mobility so it should be close at hand.

Andrew Hammond II

Southern Cross 28

Noank, CT

We assume you mean is a stern anchor that you can quickly deploy from the ockpit. A stern anchor can be used for three distinctly different purposes.

Mediterranean moor (bow-to shore tie). The anchor will be set in the normal manner and must hold without dragging even a little. Choice will vary by bottom type, but generally, a conservatively sized claw, pivoting fluke, or a new generation, quick-setting anchor with a adequate chain and possibly a kellet will work. The chain (or kellet) is needed only to keep the rode free from passing boats.

Kedge (pulling the boat off a soft grounding). Minimum weight is important, since this is often deployed by dinghy. An alloy Fortress is a good choice, with no chain. A cut resistant leader may be helpful (see PS August 2018) but chain isn’t necessary. Why no chain? The rode length for kedging is usually long (20:1 scope is not unusual), ensuring a good angle of pull, and even with chain, kedging loads will likely lift any catenary in the chain. Also, you want to avoid a downward angle of pull when you are trying to pull off a shoal. Your best choice is a very long rode, a lightweight alloy anchor, and no chain.

Emergency stopping. In effect, an emergency stop requires ground tackle similar to what is required for Med mooring. Bigger boats often have stern rollers and hawse pipes to facilitate deployment, but this would be an expensive solution in your case. Often, you can quickly reduce boat speed with a sharp turn (into the wind if sailing). A fast turn followed by rapid deployment of the bow anchor can avert a collision.

In most cases where an anchor is required to stop the boat quickly, the bow anchor is used. This is why it should always be ready to deploy when there is a risk of collision or grounding.

Some singlehanders use quick-release shackles (opened by lanyard led to the cockpit) to deploy their bow anchor from the helm. The scope can be pre-established for the expected depth and the rode must be clear to deploy without tangles. This arrangement is complicated, but we’ve seeen it done.

If you insist on a stern anchor for this purpose, avoid Danforth or Fortress types, which might be slow to set if the boat is moving fast. You want enough weight and chain to get the anchor to the bottom quickly. A claw or quick-setting Delta-style anchor will likely be your most affordable option. A 22-pounder with six-feet of 5/16 chain should be adequate, and could double as backup to your working anchor.

The point here is that no single anchor works for shore anchoring, kedging, and emergency stopping; these are three different tasks and require different gear. In my case, I use the bow anchor for stopping, and a Fortress with rope rode for kedging and shore ties (adding a kellet for the latter).

- Drew Frye

Technical Editor Drew Frye is the author of Rigging Modern Anchors (Seaworthy Press, 2018). He blogs at www.sail-delmarva.blogspot.com. For more on anchoring, see Practical Sailor’s five-volume ebook “Anchors - The Complete Series,” www.practical-sailor.com/books.

Comments (11)

The anchor in the above image appears to be correctly identified as a Lewmar Claw. This is a relatively low holding capacity anchor.

Posted by: Drew Frye | March 16, 2019 12:45 PM    Report this comment

The Delta has been shown not to be the best anchor. You use it in the picture. Time to update.

Posted by: Sailorlady | March 10, 2019 9:33 AM    Report this comment

I've had 3 engine failures. Using a stern anchor would have resulted in either grounding or collision in each case. I used my momentum to coast into a better spot and anchored from the bow, no fuss, no muss. On of these was between a pair of jetties with a 35-knot cross wind. I costed towards the windward jetty, dropped close, and drifted back, just short of the other jetty. A stern anchor would have put me on the rocks.

Stern anchor. 10 seconds to detach and deploy = 83 feet. Because I am moving at 5 knots and will hit the anchor with thunder storm force (tested, not a guess), I need 10:1 scope = (8+3) x 10 = 110 feet. With impact, another 10 feet drag in plus stretch, so 203 feet.

Bow anchor. Spin into the wind and carry about 1/2 boat length (conservative) upwind = -15 feet. The anchor will be on the bottom by the time the boat stops (each time I actually had to wait a few moments) = 0 feet. Because I am using my best anchor and am only drifting, I can slowly snub and control the vessel, stopping at 5:1 scope = 55 feet. Total, about 40 feet down wind of my starting position.

There are four advantages to using the bow anchor: you can use your momentum to go in a beneficial direction, you can kill momentum by turning, because you stopped, things happen more slowly, and you are using your best anchor. Certainly a stern anchor can be used for many things, including stopping, but the bow anchor is most often the better choice.

Finally, don't waste much time trying to restart the motor. You need that time.

Posted by: Drew Frye | March 8, 2019 3:31 PM    Report this comment

Hi, and thanks all for your help. When motoring in after a sail, the channel depth trends shallower, running roughly from 12' to 8'. Heading north at 4kt, as soon as I reach the second of two daymarks, I turn 90 degrees to the west to head to my mooring; rocks mark the eastern side of the channel, which are my concern in the event the diesel ever conks out (given the prevailing westerly winds which would drive me into them). The diesel runs well and the yard maintains it regularly, so this is a "just in case" preparation. Sounds like the 22 lb. claw with 6' of 5/16" and say 100' of three-strand nylon ought to work? More specifically, I do want want to note that the channel is wide enough for two large boats to comfortably pass, with roughly 15 feet between them. So, if I lost power during my channel run, I risk damaging another boat, or possibly running into the rocks. My emergency anchor drop would need to be quick, in about 8' of water while moving northerly; if I lost power before the daymarks, the depth is such that I could run into the shallows (mud); if I lost it in the daymark area (to port), I'd have to continue moving northerly, but risk the easterly nudge of the wind.....

Posted by: adrift | March 3, 2019 5:22 PM    Report this comment

Related question: I've always carried a spare anchor/rode (presently a Fortress w 30' of chain and 200' of nylon), but have never deployed it. Any tips on how to set/recover as a stern anchor to prevent swinging in close quarters (like along the ICW)?

Posted by: H dock | March 2, 2019 5:28 PM    Report this comment

Every commercial work boat has a stern anchor.

Lets remember WWII landing craft with their Jimmy Diesels running full out stopped short of the islands throwing out a 33 lb cast iron Danforth attached to a heavy wire power winch. I have one these beauties. So you don't need a heavy anchor to stop. But you do need a long scope of sturdy rode say 1/2' line. Keeping the Danforth style anchor on the stern rail with a long rode in a accessible bag readily deplorable marks the boat as being managed by a "seaman". A total investment of a few hundred bucks can "save your day".

Peter I Berman
Norwalk, CT
Author of "Outfitting the Offshore Saiboat" Paracay Pub.

Posted by: Piberman | March 2, 2019 12:46 PM    Report this comment

When I cruised my Cal 30 I carried three anchors and four crossing to Hawaii and up to Washington. In the California Channel Islands we often anchored bow and stern to keep swinging around into other boats. My bow anchor was a 25 lb CQR and my stern and spare were 12H Danforths. I kept a 35 lb CQR amidships for a storm anchor that I never had to deploy, although I often swung off two bow anchors in a blow. Now that I putter about in a Merit 22 modified with a bulb keel, I carry two 13 lb Danforths in the stern lockers ready to deploy, one with the bitter end secured to toss over the stern. The other is is a bag ready to carry to the bow, Both have a boat length of chain and plenty of rode. Interestingly, on my Cal 30 I did also carry a kellet weight and used it a few times.

Posted by: Hedgie | March 2, 2019 11:31 AM    Report this comment

When I cruised my Cal 30 I carried three anchors and four crossing to Hawaii and up to Washington. In the California Channel Islands we often anchored bow and stern to keep swinging around into other boats. My bow anchor was a 25 lb CQR and my stern and spare were 12H Danforths. I kept a 35 lb CQR amidships for a storm anchor that I never had to deploy, although I often swung off two bow anchors in a blow. Now that I putter about in a Merit 22 modified with a bulb keel, I carry two 13 lb Danforths in the stern lockers ready to deploy, one with the bitter end secured to toss over the stern. The other is is a bag ready to carry to the bow, Both have a boat length of chain and plenty of rode. Interestingly, on my Cal 30 I did also carry a kellet weight and used it a few times.

Posted by: Hedgie | March 2, 2019 11:31 AM    Report this comment

When I cruised my Cal 30 I carried three anchors and four crossing to Hawaii and up to Washington. In the California Channel Islands we often anchored bow and stern to keep swinging around into other boats. My bow anchor was a 25 lb CQR and my stern and spare were 12H Danforths. I kept a 35 lb CQR amidships for a storm anchor that I never had to deploy, although I often swung off two bow anchors in a blow. Now that I putter about in a Merit 22 modified with a bulb keel, I carry two 13 lb Danforths in the stern lockers ready to deploy, one with the bitter end secured to toss over the stern. The other is is a bag ready to carry to the bow, Both have a boat length of chain and plenty of rode. Interestingly, on my Cal 30 I did also carry a kellet weight and used it a few times.

Posted by: Hedgie | March 2, 2019 11:31 AM    Report this comment

In Europe, there are many effective ways to store, deploy and recover a stern anchor, and also store a anchor tape rather than rode.
,

Posted by: Ernie Godshalk | March 2, 2019 10:35 AM    Report this comment

I keep an anchor in the cockpit. I store the anchor in a canvas bag. I have a grommet in the bottom of the bag and the bitter end is cleated to a stern cleat. The bag holds 110 feet of rode and the anchor.

Posted by: Bud | March 2, 2019 9:39 AM    Report this comment

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