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2011-03-05

And to the bottom bind them!



Sometimes, the difference between thinking you know nothing and knowing you know something is marketing.

In a previous employment iteration, I worked as a marketer. Chomsky's notion of the manufacturing of desire and consent was in full effect. The key to selling most of the unnecessary crap in our society is based on the accessing of that nagging feeling of self-doubt in the prospective customer...the idea that they have a knowledge deficit.

When it comes to something as relatively faddish in boating as "what's the best anchor?", this feeling is rampant and tied to the fear of making a faulty choice, leading directly to a fatal mistake.

Anchors hold boats to the sea floor, but actually, they enact the same sort of physics as a spring. Energy of the wind and waves on the available areas of the boat load the spring (the rode, made of chain or rope or a combination) which pulls irregularly at the anchor, buried in the best case in the (hopefully) firm bottom material and resistant (again, hopefully) to various angles jerks, pulls and strains.

A lot of variables there, aren't there? One constant is the length of the rode. More rode equals a greater length along which the sharp tugs at the bow (modified of course via the use of bridles and snubbers) can be distributed and modified before they manifest as a wrenching yank at the shaft of the anchor. Recall that a wrenching yank is how the thing's going to be pulled off the bottom during retrieval (yet again, in hope), and it's clear how much of anchoring is about the selective balancing of forces.

That nagging feeling can come about when years of successful anchoring with some "traditional" anchor, like the Bruce or the CQR, seem to fade into a cruel joke when the new, lighter, flukier (in a good way), roll-bar-equipped, lead-tipped Wonder Anchors of the Rocna, Manson, Bulwagga, Fortress or Spade types manifest. (There are others, of course...every tenth sailor seems to forge a new type of world's best anchor).

These new anchors offer better holding, at shorter scope, in harsher conditions, on a greater variety of bottoms (not weeds, though...keep an old fisherman's/Yachtsman's disassembled in the forepeak for that) than all their venerable predecessors.

It has led, in my experience, to hearing sailors with long and unblemished years of successful anchoring (as in "we didn't drag the anchor and we always got it back and we didn't swing into a more expensive boat, either) feel like they were anchoring know-nothings; that they were missing the boat, so to speak, by not relegating the "old hook" to the bilges in favour of some orchid-shaped, two-grand chunk of Big Scientific Anchoring, yo.

If you have successfully anchored without dragging in a variety of conditions, then I submit it to you that you do in fact know something. Possibly more than is justified for the outlay of The Holy Hook.



A lot of these arguments about "which anchor" seem to me to dead-end at a couple of points. The first is the marketing-driven contention or, less dogmatically, the suggestion, that there is, or could be, a single "do it all" anchor. Car drivers have (at least where I live) the habit of switching from "summer" to "winter" tires, and benefit thereby, even given the greater friction and lower gas mileage when running on winter tires. That's the price we pay for greater stopping power on slick, icy or slushy roads.

All drivers (except those who work for tire manufacturers) appear to largely agree that "all-weather radials" are a compromise best left to people who get two weeks of cold weather a year. The Quixotic quest for "the one anchor to hold them all/And to the bottom bind them" is equally a compromise. Even our colleagues and fellow-sailors from Fortress, Spade and Rocna will admit, grudgingly, that their products won't do any better (and perhaps a lot worse) in weeds and rocks and certain other sub-surfaces.

The second point is that some old salts (or just new salts who've been paying attention to old salts) seemingly "get by" with feeble, discredited older anchor designs, such as the Bruce, popular on the Great Lakes still, because they a) never anchor in bottoms where the Bruce's deficiencies will manifest, or b) possess proper anchoring technique of knowing correct rode length, the use of chain, the use of kellets, snubbers and bridles and even diving on the anchor to ensure it has set firmly.

In other words, how much of the vaunted superiority of the new style of anchors can be attributed to the fact that they are forgiving of inadequate scope, inadequate chain, generally lax technique and so on?

Could it be that sailors who know how to anchor properly and to the conditions can make any well-made and time-tested anchor work? Could it be that those who regularly drag, break free, fail to reset or drift down on their fellow sailors lack the experience or the initiative to lay out sufficient scope, to rig bridles or even to know that the anchorage is not safe and that they should run to sea?

Speaking of which: How often does "running to sea" get listed under "anchor strategies of known success". And yet it is an important part of seamanship, knowing when to bug out in the face of gear-destroying conditions. It's very much in the same realm of seamanship as "reefing early and often", as it is focused on reducing forces destructive to the boat or unsafe to the crew.



I do in fact think that the newer, lighter, broader, roll-bar-equipped designs have merit, and probably enough to persuade me to whip out the wallet when the time comes to equip the steel boat with a "dedicated primary". But I also contend that it is not always the inadequacies of previous long-standing (and long-holding) designs that is to blame, but the sometimes considerable lack of experience of the person standing over the anchor locker.

As for me, I'm going to transfer a couple of anchors back to Valiente this year and do some more experiments. You can never have too much anchoring practice, and my back needs a work-out!

Addendum, March 19, 2011: Looks like I'm getting a Fortress to play with this season. This will allow me to put the 'venerable' CQR (very common here, as are the Danforth for "lunch hook" and even the old Bruce (every second boat) to the test, or rather, just to see if I can duplicate the results I've seen elsewhere that shows the CQR failing to set quickly. They are going to look at me funny off Hanlan's Point, where the phrase "sandy bottom" refers to the nudist sunbathers rather than what the snorkeller reports.

Meanwhile, in the blogosphere, the bars and the bull sessions, the debate rages on and the slagging is public and intense....and not particularly illuminating.

The line between anchor and wanchor is about 4 mm of Dyneema, it seems.

I would, for my own purposes, simply like to establish baselines which have largely (but not completely) eluded my notice in this nearly decade long (has it really been 10 years?) bunfight over "who has the better anchor?"

Baseline 1: That the various "newer style anchors", such as Manson, Rocna, Sarca, Bulwagga, Spade, XYZ and any I've missed, are, due to advances in design and metallurgy, better qualitatively than the "old school" CQRs, Bruces, Danforth styles.

Baseline 2: If Baseline 1 is accepted (a big but arguably provable "if"), then I want to know if the new style anchors merely allow for worse technique (short scope, no kellets, bridles, insufficient backing down), or work as well when all anchors are judged with the same accepted 7 to 1 scope, bridles, snubbers, kellets, etc. My impression is that the newer style reset quicker and this obscures the fact that proper scope would not have required a reset in most bottoms.

Baseline 3: I want to know which anchors fail or perform worse in what bottoms. The quest for "one anchor" for all situations is false, I think, otherwise who would still carry a Yachtsman/fisherman's...but people still find it's superior in heavy weed and sometimes rock bottoms. The fact that it largely sucks everywhere else doesn't apply. Me, I want an all-purpose primary. Then I want a stern/bower/secondary for insurance/flexibility (like Bahamian mooring in tidal streams, or to counter expected wind shifts). So I want the second anchor to do OK everywhere, but particularly in conditions where it is known the first anchor is sub-optimal or merely "average".

It is difficult to test for such conditions, and it appears to be even more challenging to find anchor makers willing to talk honestly about their products that allows that it might not be perfect in loose silt during a Cat 5 hurricane.

Me, I don't need perfect. That's unreasonable. But if a CQR is as good as a Rocna at 10:1 scope on all-chain, with waterline snubbers and a bridle off the deck and a kellet on a messenger line suspended five feet off the sea floor, then why would I buy a Rocna?

Isn't it cheaper just to learn how to anchor properly? Why buy a product that merely compensates for one's ignorance of the physics of a catenary? People who regularly anchor, such as my esteemed commentator below, have the habit of actually diving on the hook, looking at the state of the set, the composition of the bottom, the proximity of other debris nearby and so on. The biggest problem doesn't seem to be the type of hook, but other boaters who drag because they seem unclear (or indifferent) to some anchoring basics.

2011-03-02

Relativity and your house bank


This is a cut and paste of an article recently posted in the Economist that some might find interesting. I don't usually do wholesale c 'n' p as a blog post, but I found this information new and thought-provoking. So much of our technology is prosaic in the extreme (the simple lead-acid battery would be an example of this) but often we "end-user" are ignorant of what fundamental physical laws and processess are being levered for our convenience.

Summary: The lead-acid battery is an old and well-understood technology, but you can't understand its basics without invoking Einstein...something I had not heard before.

From the article:

"ALBERT EINSTEIN never learned to drive. He thought it too complicated and in any case he preferred walking. What he did not know—indeed, what no one knew until now—is that most cars would not work without the intervention of one of his most famous discoveries, the special theory of relativity.

Special relativity deals with physical extremes. It governs the behaviour of subatomic particles zipping around powerful accelerators at close to the speed of light and its equations foresaw the conversion of mass into energy in nuclear bombs. A paper in Physical Review Letters, however, reports a more prosaic application. According to the calculations of Pekka Pyykko of the University of Helsinki and his colleagues, the familiar lead-acid battery that sits under a car’s bonnet and provides the oomph to get the engine turning owes its ability to do so to special relativity.

The lead-acid battery is one of the triumphs of 19th-century technology. It was invented in 1860 and is still going strong. Superficially, its mechanism is well understood. Indeed, it is the stuff of high-school chemistry books. But Dr Pyykko realised that there was a problem. In his view, when you dug deeply enough into the battery’s physical chemistry, that chemistry did not explain how it worked.

A lead-acid battery is a collection of cells, each of which contains two electrodes immersed in a strong solution of sulphuric acid. One of the electrodes is composed of metallic lead, the other of porous lead dioxide. In the parlance of chemists, metallic lead is electropositive. This means that when it reacts with the acid, it tends to lose some of its electrons. Lead dioxide, on the other hand, is highly electronegative, preferring to absorb electrons in chemical reactions. If a conductive wire is run between the two, electrons released by the lead will run through it towards the lead dioxide, generating an electrical current as they do so. The bigger the difference in the electropositivity and electronegativity of the materials that make up a battery’s electrodes, the bigger the voltage it can deliver. In the case of lead and lead dioxide, this potential difference is just over two volts per cell.

That much has been known since the lead-acid battery was invented. However, although the properties of these basic chemical reactions have been measured and understood to the nth degree, no one has been able to show from first principles exactly why lead and lead dioxide tend to be so electropositive and electronegative. This is a particular mystery because tin, which shares many of the features of lead, makes lousy batteries.

Metallic tin is not electropositive enough compared with the electronegativity of its oxide to deliver a useful potential difference.

This is partly explained because the bigger an atom is, the more weakly its outer electrons are bound to it (and hence the further those electrons are from the nucleus). In all groups of chemically similar elements the heaviest are the most electropositive. However, this is not enough to account for the difference between lead and tin. To put it bluntly, classical chemical theory predicts that cars should not start in the morning.

Which is where Einstein comes in. For, according to Dr Pyykko’s calculations, relativity explains why tin batteries do not work, but lead ones do.

His chain of reasoning goes like this. Lead, being heavier than tin, has more protons in its nucleus (82, against tin’s 50). That means its nucleus has a stronger positive charge and that, in turn, means the electrons orbiting the nucleus are more attracted to it and travel faster, at roughly 60% of the speed of light, compared with 35% for the electrons orbiting a tin atom. As the one Einsteinian equation everybody can quote, E=mc2, predicts, the kinetic energy of this extra velocity (ie, a higher E) makes lead’s electrons more massive than tin’s (increasing m)—and heavy electrons tend to fall in and circle the nucleus in more tightly bound orbitals.

That has the effect of making metallic lead less electropositive (ie, more electronegative) than classical theory indicates it should be—which would tend to make the battery worse. But this tendency is more than counterbalanced by an increase in the electronegativity of lead dioxide. In this compound, the tightly bound orbitals act like wells into which free electrons can fall, allowing the material to capture them more easily. That makes lead dioxide much more electronegative than classical theory would predict.

And so it turned out. Dr Pyykko and his colleagues made two versions of a computer model of how lead-acid batteries work. One incorporated their newly hypothesised relativistic effects while the other did not. The relativistic simulations predicted the voltages measured in real lead-acid batteries with great precision. When relativity was excluded, roughly 80% of that voltage disappeared.

That is an extraordinary finding, and it prompts the question of whether previously unsuspected battery materials might be lurking at the heavier end of the periodic table. Ironically, today’s most fashionable battery material, lithium, is the third-lightest element in that table—and therefore one for which no such relativistic effects can be expected. And lead is about as heavy as it gets before elements become routinely radioactive and thus inappropriate for all but specialised applications. Still, the search for better batteries is an endless one, and Dr Pyykko’s discovery might prompt some new thinking about what is possible in this and other areas of heavy-element chemistry."


Here's a bonus link for those readers who, like me, have found how refitting a boat has been an exercise in the history of technology, i.e. no matter where you are aboard, some fluid needs pushing uphill for some reason. As a result, one learns about hydraulics and physics, AND one gets wet. Thought I might say "or" there? Wrong. The skipper get wet even when he doesn't screw up once. It's "Neptune's fee", I suspect.

Anyway, behold The Toaster Project: one man's quest to smelt a humble chunk of technology.