A Question Of Scale—Anchor Size

This summer will remain in my memory as one for strong winds and great sailing. By the time we reached Scotland in early July we had just about seen the last of the light winds that we had enjoyed in West Cork, and a more mixed regime had set in. No matter—these were ideal conditions to get to know our boat better, and economize on fuel!

Plenty of anchor work, too, and several nights of winds that reached gale force let us test our anchoring system out in the real world. In nearly all circumstances we tend to lie to one big anchor and plenty of chain, and it has never failed us yet. But if we’re expecting really strong winds, in poor shelter, or expect a big wind shift, out will go the second set of gear.

When we planned the boat, we knew that we would have to work out a custom installation to handle the second cable and anchor. There was not enough room in the anchor locker for two sets, and the stemhead and rollers were not ideal to keep a second anchor permanently stowed alongside the bower anchor, a 33kg Rocna with a big rollbar.

So we had an additional tang welded to the deck and had a roller drum fabricated to handle the second cable, to be bolted in place on deck when needed. In normal circumstances this is lashed down in our stowage area forward, and is lifted on deck via the spinnaker halyard when needed. Once in place we can attach whichever anchor we want to the chain (25kg Rocna, Fortress or fisherman) and run it out either under our own power or via the dinghy, and once set up it all works really well.

So when we were preparing for the first big blow of the season we decided to set up the second anchor ready to face the worst of it. Working together in only moderate winds we were amazed at how much time it took to get everything in place and ready to go—well over an hour. Admittedly we hadn’t set it up for over a year, so we were out of practice and there was far too much time spent looking out the right bolts, finding the mousing wire and so on, but it was sobering to think how long it might have taken in wild conditions.

Now we do have a third cable that is simply coiled ready to go for our stern anchor, but it’s a lighter set up, and it wouldn’t be our preferred solution, so it’s going to be back to the drawing board this winter to come up with some effective ways of speeding up the deployment of our second system. And, once again, we were reminded how glad we are that our primary set up is scaled up so much.

Which got me thinking about the perennial question of how much anchor is enough? To my eyes so many owners err on the small side, and I can’t quite understand the logic of it. I know that there are negative cost and weight implications for going for (at least) the next size up from the manufacturer’s recommendation, but what else is gained? And when the wind gets up who is glad to be lying to a smaller anchor?

Going up a size offers so many benefits: A heavier anchor will set faster and dig through a hard substrate more effectively. Bigger size means more working surface area for more effective holding, especially with new generation anchors like the Spade and Rocna. And if, as far as our observations are concerned, most boats are nearly always anchored to one set of gear, doesn’t it make the most sense to scale it up, so that when the wind comes up unexpectedly you can face it with confidence and sort out the second set of gear? Running out a second anchor is often far more work than anticipated, and may have to be done in less than ideal conditions. I suspect that’s why so many people put it off if at all possible, and then end up having to set it when conditions are at their worst. Making your primary set-up oversized and bombproof has a lot going for it.

Like many others I suspect, I suffer from the syndrome called “anchoring insomnia”, sleeping with one eye open when lying to the hook in remote places—and rightly so. But I have to say that for me scaling up on our anchor and gear has had more beneficial effects in curing that affliction than all the pills in the world would, and so whatever the downsides to heavier ground tackle, I think they are a price well worth paying.

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Colin

Colin, European Correspondent here at AAC, is a deeply experienced offshore sailor who holds a Yachtmaster licence, and a gifted photographer and talented writer who has added a whole new dimension to Attainable Adventure Cruising. In addition, since Colin and Louise are from England and had their OVNI 435, Pèlerin built in France, they bring a European perspective to our site. You can read more about Colin and Louise and their business at their website.

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  • Evan Selbiger Mar 9, 2011, 6:23 pm

    There is nothing wrong with upsizing your anchor, but keep in mind the windlass must be capable of holding that much extra weight. The relative holding power of an anchor comes from its effective surface area, not from the weight.

  • Colin Speedie Mar 10, 2011, 6:34 am

    Hi Evan

    Good point – especially as most boat builders do not take this into account – from my experience windlasses supplied as OEM are undersized – just like the anchors that accompany them.

    One of the first things we had planned when we were developing the specification of our boat was the ground tackle, though, and we went for a windlass 50% more powerful than the standard model to cope with our heavy gear, and so far it has performed flawlessly – the retrieval rate is faster too, which is an additional bonus.

    And I’d agree about the surface area equating to holding power, definitely one of the main reasons that the ‘new generation’ anchors like the Spade and Rocna are so effective, but for a bower anchor I believe that extra weight is essential in difficult conditions, and really helps the anchor to dig in.

    Best wishes

    Colin

  • Kettlewell Mar 11, 2011, 11:47 am

    A couple of thoughts. Many boats these days have anchors and chain that are so heavy they can’t easily pull the mess up when the windlass breaks, which it will do at the most inconvenient moment. A voyaging boat needs a backup system that can be used when the windlass isn’t working. Second, with a lightweight second anchor, like a Fortress, already hooked to a mostly nylon rode and ready to go, it is literally a matter of minutes to deploy in the dinghy. Or I can drop it off the bow in seconds. I do this frequently to limit swing, or as a precautionary measure if the weather is threatening. I personally think it is often easier to set the second anchor once in awhile than it is to handle overly heavy gear day in and day out. Yes, your primary should be able to handle anything up to 40 knots or so, but it shouldn’t be so heavy to use that you can’t do it without mechanical aids.

    • John Mar 11, 2011, 8:57 pm

      Hi John K,

      I certainly agree that having a light weight secondary anchor ready to go is a good idea.

      However, on the size of the primary, I would not want to be regularly anchoring on gear that was only reliable to 40 knots. Our thinking is that, even on a perfect summer afternoon in Maine, a thunder storm can come up with little warning (perhaps when we are ashore) and easily produce gusts of well over 50 knots.

      So our way on Morgan’s Cloud is to always anchor on our best bower (120 lb SPADE) that has proven itself in winds of well over 70 knots. While this does impose a bit more load on the windlass, it is nothing that any good unit can’t handle, as ours does, day in day out. Even if we were to go down in size to say a 60lb SPADE or Rocna, we would still not be able to raise it and any amount of chain by hand. This is why we carry a spare windlass motor (never used) and have a windlass with a hand crank option.

  • Kettlewell Mar 11, 2011, 11:43 pm

    It depends upon the bottom, but I wouldn’t be surprised if a 60 lb Spade could handle 60-70 knots in your boat. I believe a well dug in anchor in good holding ground will basically hold anything the anchor chain and line will take, which is a lot. But, personally, based on my experience, if you didn’t feel comfortable with the 60 lb Spade I think it would be easier to also set a nice Fortress at about a 45 degree angle or so and you would have superior holding to your 120 lb bower, plus you would have a backup rode out there, and it would all weigh less in the bow of your boat. But that is only preference based on my 30+ years of cruising, and I think a lot of people agree with you based on what I am seeing out there. It is interesting, because when I started boating my philosophy was more prevalent—go with lighter gear and then go with a second anchor if you need to. But what I use today would have been considered ridiculously heavy 30 years ago, and what a lot of long-distance cruisers use would just not have been on the radar screen. I suspect that is partly because we all used to use Danforth anchors and almost nobody had a windlass, powered or otherwise. We had to use lighter gear!

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