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Safe anchoring

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Before you start, you should know how to stop! The ability to anchor securely is absolutely essential. Clearly, the dangers of a rocky coast are obvious enough, but even in a river, if your engine fails you can be carried downstream, into the stone pier of a bridge, or the turmoil of a weir. Even on a lake, an anchorless boat will be blown to leeward, and by Professor Sodde's universal law there will be something hard or sharp to greet her. The happy owner of a new boat may be eager to set off under power, just for an hour or so, to get to know her. But if the engine packs up just a few hundred yards from the quay; it's almost certain that the most sensible thing to do will be to drop an anchor. Afloat, that's the equivalent of parking by the roadside. With the boat 'parked' you can take your time. No panic. But a degree of panic is extremely likely if the owner - anxious to try his new boat - hasn't given thought to his anchor and cable; his 'ground tackle' as it's commonly called. Panic, to fmd a shackle (the pin is sure to be stuck - where's the pliers?). Haste, and bruises, as the chain is dragged on deck and the anchor is manhandled from a cockpit locker to the foredeck. Alarm, while the boat drifts steadily toward an embarrassing or even dam­aging encounter. You've got the message - prepara­tion is the foundation for good sea­manship. Anchor and cable must always be ready to let go, even for the shortest trip. Remember, if you can't make the boat go where you want her to go, you must be able to prevent her going where you don't want her to go. Only on a long passage in the wide blue ocean, where the water is too deep for anchoring, is it reasonable to stow all your ground tackle. Scope is the word Although you may have read some very technical analyses of the loads imposed on ground tackle, anchoring is in fact a simple business. With ade­quate gear, and common sense, success is guaranteed - well, almost. You just follow the simple rules used by generations of practical skippers. The fIrst rule is to have a suffIcient length of cable under water. An anchor works by digging into the bottom (mud, shingle or sand). Obviously; it can't dig down if the cable is pulling it upward. So the general rule is to 'veer' (payout), a length of chain at least three times as much as the depth of water. When all is calm and quiet, most of the 'rode', as an anchor cable is called, will be lying along the bottom, but when a sudden squall drives the boat back, the long rode lifts into a curve, and the pull at the anchor is still virtually horizontal. With a rope rode you need at least five times the depth, and with either chain or rope, longer is better, provided the circumstances allow, as when there's plenty of space to swing without either fouling another boat, or fmding yourself on the mud at the edge of the creek. It's when a boat is pitching and jerking at her cable in heavy weather and rough water, that you want a good length and weight of cable to absorb the shock loads before they can unsettle the anchor. Your boat, too, needs some ease­ment from the repeated shocks of a snubbing cable, which can even cause damage in really rough weather. The thumps that shudder the whole boat can also be terribly disconcerting to her owner; you feel for your boat. Absorbing the shock There are two schools of thought on ways to absorb the fearsome shocks of a snubbing cable; some favour the weight of chain, some favour the elasticity of rope. The curve of a chain hanging between two points is called a 'cate­nary' by engineers - appropriately, it happens to be a word taken from the Latin for chain. As the boat pulls back, tending to straighten the curve, the weight of the chain must be lifted, so some of the energy is absorbed. The longer and heavier the chain, the greater its shock-absorbing power. But when the wind is really strong, and the waves are big, a chain can be as near straight as it ever will be, and its shock-absorbing power is lost. Those who favour rope claim a better shock-absorbing power. Nylon rope is more elastic than Terylene, as well as being stronger. In fact, stronger types of rope do exist, but are either less flexible or more sus­ceptible to chafe, as well as being more expensive. There are also cheaper ropes such as polythene and polypropylene, but they're useless for rodes because they float. So nylon is the choice for a rode. When you're lying to your anchor in a gale, and the hammer-like thumps of a snubbing cable are too much to bear, a good way to increase the shock-absorbing power of your rode is to restore the catenary curve by sliding a heavy weight down it on a big shackle - with a line attached to haul it back again, of course. Lower it to a point about half way. Yes, I've seen abstruse theories that say otherwise, but sixty years of anchoring a variety of boats tells me that half way is the best position. My own amateurish mathematics says the same. Better still, you can test it in the garden: tie the clothes line to a tree, hang a good weight in the middle and pull. Then move the weight to the 'anchor' end, close to the tree, then try again, and feel the difference. On a thirty foot boat, I've been accustomed to use an iron pig weigh­ing about 40lb, which is really as much as a man can sway over the bow. Yet even that is no more than the weight of an extra five fathoms of my %in chain. Veering more chain is a far easier way of adding weight, provid­ed, as I've said, that there's plenty of space for the boat to swing. In short, a cable pig has merit when space is constricted. A shackle of chain We use shackles to join chains and ropes, but the same word, 'shackle', is an old term for a length of chain. Nowadays, chain is sold by the abrasion by stones, broken shell and, in some popular anchorages, even broken glass, on the seabed. Its weight also helps to keep the cable down so that the pull at the anchor is nearly horizontal. Rope is lighter than chain to haul back on board. On the other hand it's not 'self-stowing'. Chain will drop by its own weight through the 'navel pipe' into its locker below the fore­deck. Rope will rarely do that: it has to be coiled, or perhaps stowed on a reel - a good idea if you can fmd space for a suitable size of drum. Chafe is a great danger to rope, so it must be protected where it comes over the stemhead fitting or through a fairlead. It can be wrapped in canvas, or leather - 'parcelled' in nautical lan­guage. Alternatively, a length of stout polythene tubing can be split, to be slipped over the rope at the danger point. A couple of lengths of small line will hold it in position. Marking your cable An anchor cable must be marked in some way, so you know how much you've veered. How you do it is up to you. The old textbook way of tying strips of leather, cut with one, two or three tails so that a deckhand could judge by feel in the dark isn't much used by private owners, who have the benefit of electric light of one sort or another. With chain, the easiest way is to to paint one, two, or three seg­ments. Paint can also be used on rope. Weaving in pieces of leather or thinner cord is another way. It's the marking 'code' that really matters. If you think 2-3 metres is the minimum high tide depth in which you're likely to anchor, then the first mark can be set at three times three with chain, or five times three with rope. The second mark could be at double that length - there's not much point in trying to mark every metre; it's easy enough to judge intermediate lengths. Some people paint the first mark in red, the second in white, and the third in blue, reasoning that every­one knows the sequence of red, white and blue. Some old books recommend that when you're going to drop your anchor, the required length of chain cable should be hauled out, and ranged on deck before letting go. That's not my choice; you need more deck space than can be found on most yachts, it's hard work, and there's a danger to feet and legs. Payout your cable directly from its locker, up to the chosen mark. Then, when the anchor is actually set (see previous page), and you can see your cable hauled out ahead at a long, low angle, you can easily judge that you've veered enough. Setting the anchor It's not a good idea simply to drop your anchor with a good run of chain, and leave it to its own devices while you put the kettle on. You need to be sure that your anchor is 'set' - firmly dug in - before you can relax. Give it a good firm pull, at a low angle, to drive it in. If there's no wind or tide, you can put the engine astern, drop the anchor, and payout chain steadily as the boat moves away. When you've veered sufficient cable, make fast with a couple of turns, and the boat will come up abruptly, straightening the cable and bringing it up to the surface. That's when your eye will tell you if you have a good long scope, leading to the anchor at a shallow angle. A good tidal stream, or a head­wind, will carry the boat astern in the same way without need of the engine. When you feel that the anchor has bitten and the boat is settled, make a note of your position by noting 'tran­sits'. Look to port and starboard for any marks on shore which can be lined up; trees, beacons, buildings, even a big stone on the beach with a stain on the cliff beyond. Until the boat swings with wind or tide, your transits will confirm that you're holding the same position. If not, then the anchor is 'dragging'. Should that happen, and you find that you're moving back toward the shore or another boat, it's obviously useless to shorten the cable in the hope of keeping away from danger. A shorter cable will only make matters worse. Start the engine, lift the anchor and fmd a better spot. Nearly every skipper-owner seems to develop a sense which tells him that the boat is either swinging to the tide or dragging - even at three o'clock in the morning. If you have a chain cable, the grating noise as it rumbles across the seabed to a new position is transmitted through the hull to your ears. You become familiar with the sound, especially if you sleep in the fore part of the ship. Experience alone teaches the differ­ence between that innocent sound and the noises made by a dragging anchor as it bumps its way along the bottom. It's the difference between staying snugly in bed and having to go out on deck. In passing, forgive me if I introduce a sartorial note: I find a brushed cotton tracksuit better nightgear than pyjamas. If you do have to go on deck, you stay warm, and you look less deshabille!

 

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