Once Is Enough

by Miles Smeeton

  I have called this story Once is Enough, but once is never really enough in any worthwhile sport. The mountaineer coming down from a high mountain may look over his shoulder and say, ‘Well that’s that. Never again!’ But no sooner is he down at the base camp than he is wondering whether another route will ‘go’. The same with a yacht and Cape Horn. Once, or twice, may be enough for Beryl and me and Tzu Hang, but certain it is that other yachts will still try it. Some will be successful, and some like us will fail. It isn’t a trip to be undertaken lightly, however good the ship, and the story of our passage and the experience of what might happen to a yacht like Tzu Hang in those big seas, may add its little molecule to the mountains of knowledge of ships and the sea.

  We asked too much of Tzu Hang, and she gave us of her best. On each occasion she brought us safely home, which is all that a good ship can do. Now—bless her—fully equipped again, she is lying at anchor in Mulroy Bay, and Pwe, grown stout and placid in quarantine, and the dog, Poopa, are messmates once more. Sometimes a letter comes from John, still on his way across the seas in Trekka, and often we think of the days together in Tzu Hang, and then we wonder, on those two days of her trial, how we could have helped her more.

  On the first occasion if we had had a sea-anchor out on the end of our rope, a really good sea-anchor, with wire strops to a thimble, and shackled to a swivel fastened to another thimble in the end of the rope, and if we had used oil at the same time—a constant flow from a special tank—to smooth the sea in our wake, we might have avoided the somersault, which I am quite certain we made.

  The other time, if somehow or other we could have made Tzu Hang lie four points off the wind, rather than broadside to the sea, we might have escaped damage again. Perhaps if we had sent a very small and very strong riding sail from the mizzen, as trawlers do, and if we had streamed a sea-anchor from the bow, we might have done so.

  If I was to take a small ship in another attempt to round Cape Horn, and I mean round Cape Horn on the old sailing-ship route, I would have one built. She would have broader beam than Tzu Hang and shallower draught, and then perhaps she would not be bowled over, if due to some misadventure I was forced to lie a-hull. She would be a ketch again, with very much shorter masts of almost equal height, and the only deckhouse would be amidships over a self-draining cockpit, so that I would avoid gaping holes in the deck. I would hope that her hull design would let her ride to a sea-anchor by the bow, with a very small and stout riding sail, or safely by the stem, and I should have a built in tank of oil, and most important of all I should want Beryl. Unfortunately I don’t think that this dream ship would be much good anywhere else.

  As a result of it all I think this: there are gales and seas which a good ship, a yacht, will come through whether she lies a-hull, heaves to, or runs before; and there are gales and seas, particularly in the higher latitudes, which a ship may sometimes meet with, which she will be lucky to survive whatever she does. Man does his best, but in the end something else intervenes. It may be the Pilot of the Pinta, who sometimes, for no accountable reason, brings ships home, and sometimes, for no accountable reason, lets them go.

  APPENDIX

  MANAGEMENT IN HEAVY WEATHER

  It is strange, but true, in the high southern latitudes, where seas can be 50 feet high and 2,000 feet long, they roll forward in endless procession with occasionally one sea of abnormal size towering above the others, its approach visible for a considerable distance.

  Captain William H. S. Jones, The Cape Horn Breed.

  WHEN wind and sea become too strong for a small ship, there are two alternative actions that she can take. She must stop or she must run. If by running she is closing a lee shore or going in the wrong direction, it is better that she should stop, and in order to do this she can either heave to, or lie to a sea-anchor, or lie a-hull.

  Some yachts heave to with a headsail aback, and with reefed main or a mizzen. Some yachts will heave to under the reefed main alone, or under a trysail alone, but however they do it, heaving to implies stopping under sail. In point of fact a ship hove to is not actually stopped; she is almost certain to be fore-reaching slowly, and drifting to leeward, so that her actual course moves slowly at right angles to wind and sea.

  When seas are very big and winds exceptional there are special dangers in heaving to. The ship will head up towards the wind and fall away, and as she heads up the sail will shake so violently that it tends to tear itself to pieces, or to shake the mast out of the ship, and if it is not doing this the ship tends to lie between five and six points, or more off the wind, and is in danger of being hove down by the more violent gusts, and is also in danger of taking a breaking crest into her sail, with a weight of water which will bear her masts down into the sea.

  When a ship, instead of heaving to, lies to a sea-anchor by the bows, there are also special dangers. The object is to lie with all sail down bows on to the wind and sea, and if a ship will assume a position not more than four or five points to the sea, that is taking the waves from head on to diagonally on her bow, she should be safe. There will be a great strain on her rudder as she drifts and sometimes is hurled backwards, and there is a great strain on the sea-anchor and its tackle. This must be as strong as it can be, with wire strops leading to a thimble and the thimble shackled to another thimble in the end of the hawser. The inboard end of the hawser must in its turn be spliced to a thimble, and shackled to the anchor chain, and it is advisable to have a swivel between the sea-anchor and the end of the hawser.

  A canoe will lie to a sea-anchor, a ship’s lifeboat will lie to a sea-anchor, and a small yacht may lie to a sea-anchor if she uses one big enough to hold her, but a yacht like Tzu Hang with the lighter draught of her bow and the deeper draught of her keel, with her high sheer and her foremast and rigging ahead of the centre of lateral resistance of the hull, cannot lie to a sea-anchor without some other assistance. She drags the sea-anchor round until she assumes a position little better than at right angles to the wind and sea; then she is in a worse position than if she had no sea-anchor at all, because like a pier or breakwater she is opposing some resistance to the sea, and as she is almost broadside on, she is liable to suffer damage.

  It may be that if she is a yawl or a ketch a very small and tough riding sail could be set, as trawlers do, which would hold her up to the anchor and that a terylene sail, stronger than canvas for equal weight, and less liable to rot, would be the best. For this particular purpose it must be a special sail that can be set up taut and rigid. If she will then lie bow on to the sea, this is the safest course.

  When a ship lies a-hull she is opposing the sea only with the weight of her hull and the drag of her keel; and it is possible that a light displacement yacht, steadied by a long warp streamed from the bow and stern in a loop, may even be picked up by broken water and carried sideways, without being rolled over. This happened recently to John Guzzwell in Trekka, when caught in a cyclonic storm off the coast of Queensland. But it is impossible to believe that a hawser streamed like this could have much effect on the equilibrium of a much heavier yacht.

  A yacht of larger displacement and deeper draught is rolling to leeward as the first slope of the wave lifts her, a roll increased again as the wind catches her spars and rigging as they lift over the top of the waves. If on top of this she is hit by a breaking crest of many tons weight and is knocked to leeward by this rapidly moving water, while her keel is held in comparatively still water, she will be rolled on to her beam ends, and once her masts go into the water and the breaking sea gets under her keel, she is bound to go over.

  When a ship drifts to leeward, as the water boils up under her keel, it leaves a smooth slick to weather. This slick, it is sometimes suggested, eases the sea to weather, but in fact it is only visible in a moderate gale, and in a strong gale it has not the slightest effect on the sea, only being visible for a few feet from the ship’s side. With a big ship it is probably a different story.

  When a yacht is lying a-hull
she will usually fall off and try to sail on account of the pressure of the wind in her masts; with the helm lashed down, she will come up towards the wind, lose what little way she has, and fall off again. The result is a speed of about half a knot at right angles to the wind and drifting away with it, in a diagonal course to leeward. This forward speed has absolutely no bearing on the safety of the ship, except that it seems that it would be impossible—I have never tried it—to remain within the protection of one’s oil, if oil is being used.

  So many yachts—including Tzu Hang—have lain a-hull and come through gales safely, that it has come to be regarded, although only in recent years, as a seamanlike thing to do. Now I believe that it is the most dangerous course to take in exceptionally heavy seas. There is only one thing to be said for it: it is far better to be rolled over than turned stem over bow, if you want to talk about it afterwards.

  If a yacht can lie bow on to the sea, as I have already said, I believe that she will be taking the safest course, but if she can’t do this she will have to turn her stem to the sea, using every means available to check her way. I will not use the word ‘run’ because of the danger that it brings with it and which is described in detail below.

  In the latitudes of Tzu Hang’s course from Australia, between 47º and 53º S., only the southern end of South America intervenes to break the swing of the seas as, driven by almost continuous westerly winds, they heave their way round the world. In a westerly gale when the wind can swing quickly from the north-west to the south-west, a hazardous irregular sea will build up on top of this permanent swell; more dangerous in the comparatively restricted area south of Cape Horn, but dangerous enough for a small ship even in these latitudes. If she can be kept stern on to the sea a good yacht will run on straight and true in no particular danger, even though a breaking crest may very occasionally foam over the stern so that she seems to be running in a welter of white water. It is the abnormal wave, described in the quotation at the head of this Appendix, that brings disaster.

  Soon after the accident I had a letter from Nevil Shute—amongst his many interests he is also a yachtsman—and the following description of what might happen to a yacht overtaken by an exceptional sea while running seemed to fit Tzu Hang’s case as exactly as if he had been there to see. I kept the letter and give the description now almost as it came to me.

  As a wave of exceptional form races up from aft, the first slope of the wave will lift a yacht’s stem so that she is well down by the bow. In this attitude the centre of buoyancy is probably somewhere about where it is shown in the diagram—marked ‘O’. The centre of gravity will be about where it is shown, marked ‘G’ in the diagram. The forces of gravity acting through the centre of gravity and the forces of buoyancy acting through the centre of buoyancy therefore act as a righting couple, and if the ship was motionless she would be in no danger.

  When a ship is running, even under bare poles, she may have considerable forward motion, and as the bow goes down the centre of gravity of the ship is still trying to go forward. This gives rise to a horizontal force on the centre of gravity, marked ‘I’ for inertia in the diagram, and it is opposed by a force exerted by the resistance of the water at the bow. If the angle of the boat was such that her bow went under water, the opposing force would be very near the bow, and the overturning couple would be large. This is one of the seamanlike reasons for keeping the speed low when running under bare poles.

  There is, however, another force—marked ‘IR’ in the diagram—acting through the centre of gravity. If the stem is still going down there will be an inertia force acting through the centre of gravity forwards, rotating with ‘O’ as its centre. This force might be weakening as the boat assumes the position shown, but it could be strong. These two forces, ‘I’ and ‘IR’ when combined as vectors with the gravity force ‘W’ acting through the centre of gravity, produce a resultant force on the centre of gravity, marked ‘V’. So long as this force passes below ‘O’ the ship is in stable equilibrium and the various couples are tending to right her, but once ‘V’ passes above ‘O’ they are tending to overturn her, and this could happen very quickly.

  The forward speed has a great effect on this tendency, as without it ‘I’ would not exist and ‘IR’ would be unlikely to be serious, but once the forces begin to exert their influences as shown in the diagram, the bow tends to go still further down, until the ship turns stem over bow in an inverted position.

  She is unlikely to come down in this position owing to the weight of her keel, which will tend to roll her as soon as it gets clear of the water, and she will then begin to fall over until she comes down on her beam ends. The masts will be under water—and if she hasn’t done so before—this violent roll will carry them away, and when she appears on the surface again she will be headed into the wind, facing in the opposite direction.

  He went on to point out that a suitable sea-anchor would exert a very strong righting moment on the ship if she got into this unfortunate position, and suggested that the dinghy might be used, which I describe later on.

  It is obvious that in order to avoid this danger of tripping over the bow, way must be taken off the ship. We have tried streaming a long rope in a bight from the stern, but the base of the bight is so narrow that it is ineffective. Even sixty fathoms of 3-inch rope proved ineffective, and when a breaking crest came up it carried the rope forward with it, halving its effective length.

  A sea-anchor would have to be the type already described—the R.N.L.I. pattern made by Ratsey and Lapthorne is probably the best—or the dinghy might be used. In order to do this it would have to be slung in a strong rope net like a cargo net, fitted to its hull, with rope pendants leading from the edges of the net like parachute line to a single fitting, which would be shackled to the hawser thimble. In the days of nylon and terylene the net and pendants would not have to be too heavy and could be easily removed and stowed.

  If a boat is going to lie by the stern to a sea-anchor, it is almost certain that, whatever her design, she will take some broken water over it. Her doghouse should be designed to withstand this, sloped both forward and aft, and her cockpit should be amidships. With this sort of arrangement she would be less liable to damage if heavily pooped.

  In the end, however, it will not be any one aspect of design or action by the crew that will preserve a yacht in such severe conditions, but rather the sum of them all, and the use of oil will also play its part.

  I cannot say that I have ever used oil in earnest, and the only time that I have experimented by using an oil-bag during a storm, we drifted diagonally away leaving a thin iridescent line on the surface; it afforded us no protection at all. Oil will not alter the shape of a sea, but it will smooth a breaking crest. It seems that to be used effectually it must be available in sufficient quantities and it must be easy of access. Few small yachts are equipped to use oil in any quantity, and I have little faith in small oil-bags in very heavy seas. A special tank, if there is room, is probably the best answer, with a lead through the hull, regulated by a sea-cock.

  By the time we think of using oil it is probably needed badly, but there is little point in using it unless there is enough to have an effect on the sea, or unless the ship is able to remain within its protection.

  POSTSCRIPT

  SINCE I wrote this book I have had a number of letters—mostly from well-informed sources—on the reasons for Tzu Hang’s two mishaps, and the steps that we might have taken to prevent them. All those who have spoken and written to me, who have had practical experience of the seas in those southern latitudes, or who have made the sea and waves and the shape of a ship their study, have agreed that a ship of Tzu Hang’s size would need luck as well as seamanship to come through. Particularly the old, and some not so old, salts who have sailed round Cape Horn have wagged their heads and said, ‘You should never have been there anyway; your ship was too small for those seas.’

  This was already my opinion, but two letters helped to strengthen
it. Both these letters suggested that, although the explanation and diagram of Tzu Hang’s overturning was correct to a certain extent, the major cause was probably due to the orbital velocity of a big wave. I had never heard of this theory which is that, although the mass of water in a seaway, seen as a whole, is static, each particle of water moves in an orbit round the place which it would occupy at rest. If we were to throw some rubbish overboard so that it represents a particle of water on the surface, we would see it drawn back towards the approaching swell, lifted up, carried forward, and dumped in approximately its original position again; seen from the side it would trace an orbit against the background of sea and sky.

  The important thing is the speed at which the water moves in this orbit, and for a 40-foot wave with a ten second period the speed is approximately seven knots. With seven knots on the top of the wave with the wind, and seven knots against the wind at the bottom, a 40-foot ship on the point of a 40-foot wave is subjected roughly to a seven knot push one way at her stern and a seven knot push the other way at her bow, a formidable overturning couple. A longer ship is already overcoming the push at her bow by the time her stern is subjected to the maximum thrust. The answer seems to be to keep 40-foot ships out of 40-foot seas, but if forced to run before them to tow long enough lines so that there is an effective drag in spite of the forward movement of the water on the crest and lack of a swell.

  Tzu Hang, Paris, March 1960

  William Collins

  An imprint of HarperCollinsPublishers

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  First published by Rupert Hart-Davis Ltd 1959