Selecting a Stern Anchor
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
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.