Cutting the Dragon's Tail

by Lynda Chidell

  The counterpart to the raking Chinese mast on a western yacht is the bowsprit. Beautiful as these are, they are frequently a liability when it comes to berthing or anchoring, and we were glad to have been without one.

  10.7 the steering

  We were presented with a bewildering number of alternatives when it came to working out the best steering system for Tin Hau. The rudder itself, the rudder post and the rudder port (the fixed tube through which the rudder post passed) were all detailed by Tom Colvin. But the rest was more or less left for us to work out. Not having had much prior experience of this sort of thing, I had to tackle it from first principles. I considered worm steering, hydraulic steering and the push-pull system, but concluded they all had their drawbacks, either in cost, complexity or inadequacy. The simplest solution – a tiller was out of the question with a wheelhouse. There was no room for it. I calculated that had we had a tiller, its length would have had to have been more than ten metres, two-thirds of the length of the boat! Even by adopting the Chinese system of block and tackle, attached to the end of the tiller, the length required would still have been excessive, given that we wanted to have a pilothouse.

  Having said this, our ‘emergency’ system was a two metre long tiller made of steel pipe, machined square at one end to drop over the top of the rudder post. I was careful to have an eye welded on the other end of it, the plan being to obtain additional purchase by shackling a pair of double blocks to this eye. In the event of a failure of the main steering system (assuming the rudder and its post were still intact!) the plan was to unbolt and remove the helmsman’s seat, drop the emergency tiller into position (facing aft, not the normal direction), and use the tiller immediately for steering. Should the emergency become ‘long term’, we would then rig up blocks and tackle, and sit on the settee right at the aft end of the wheelhouse, squinting at the compass.

  The whole subject of emergency steering was close to my heart, as I had had considerable personal experience of it. In my Cape to Uruguay race of 1979, our main steering broke irretrievably on the third night out of Cape Town. For the following forty-two days we relied on an increasingly worn ‘emergency’ wooden tiller. Having been through this, I was not prepared to take any chances on Tin Hau!

  Returning to Tin Hau’s primary system of steering, I realised there were two main design factors: firstly, the helmsman would have to be able to manage the wheel in any foreseeable weather in which we might be sailing; secondly, the rudder, its bearings, shackles and all linkages would have to be designed for the occasions when all attempts at steering the boat had been abandoned and the wheel lashed. Perhaps one day we would be in this situation, lying ahull in a gale. I let my imagination run wild. I visualised mountainous waves breaking hard against an unyielding four foot square unbalanced rudder. What a pounding it might have to take. And what a disaster if we lost it! With this in mind, I resolved to take the utmost care while it was still easy to do so on dry land.

  After much thought and on becoming acquainted with the size of the lazarettete (Tom Colvin’s terminology for the stern locker, at that time another new word to me) and the arrangement of the wheelhouse, I decided to adopt a system based on a large steel quadrant welded to the rudder post and connected to the wheel via a series of wire ropes, tensioners, chains and sprockets (or gear wheels such as one sees on a motorcycle). Most of the components would be situated inside the lazarettete and so would not only be sheltered and free from corrosion problems, but also very accessible for inspection and, if necessary, maintenance or repair. Figure 10 shows the arrangement as finally constructed. Although this should be largely self-explanatory, I will comment on some of the details:

  The gearing: I learnt early on from reading magazine clippings and nautical books that there would be no advantage in having the rudder turn more than thirty-five degrees in either direction. Beyond this, the advantages gained from extra turning ability would be offset by the disadvantages of braking and stalling effects. Likewise I learnt that the wheel should not be allowed to turn more than three revolutions to starboard or three to port. 1080° of wheel (three 360° turns) to thirty-five degrees of rudder represented a mechanical advantage of just over thirty, which I decided was sufficient, even with a small two foot diameter wheel (which could always be increased in size at a later date, if desirable).

  In order to achieve this mechanical advantage, I realised I would need as big a quadrant as was physically possible (item 6 in Figure10) and also an intermediate shaft with a pair of gear wheels on it, one large and one small (item 7 in Figure 10). At that time I had never heard of the term ‘slaveshaft’, but I learnt later that this is what it is normally called. By inserting this I could obtain a mechanical advantage of fifteen from quadrant to vertical slaveshaft (the ratio of the quadrant radius to the gear wheel radius) and two from the vertical slaveshaft to the horizontal slaveshaft (the ratio of teeth in the two corresponding gear wheels). By multiplying these two factors together, the desired overall mechanical advantage of thirty could be obtained.

  So far, so good; but two problems materialised. First, the lazarette, big as it was, was not quite long enough to allow room for the chains, wire ropes, shackles and wire tensioners. We solved this by creating more room; a small cut-out was made in the stern of the hull and a two-foot square box section made to house the vertical slaveshaft. Hardly noticeable from the outside! The second problem could easily have gone unnoticed until we were afloat. Luckily I thought of it in time. Whilst driving our bakkie to the hangars one day, thinking of the boat as usual, I imagined Tin Hau’s wheel being turned to starboard. My thoughts followed the action all the way down to the rudder, which I concluded would turn to port; and a rudder protruding in this direction would result in a forward moving boat also going to port. But this was not what we wanted! A wheel turned to starboard should result in a boat going to starboard. I had made a big mistake, and cursed myself for my stupidity. My immediate reaction was to find Tony. In his customary calm way he solved yet another problem without hesitation. A second horizontal shaft (item 9 in Figure 10) was added alongside the first one (item 8), which at that time was destined to be the wheel shaft. Identically sized gear wheels on these two shafts were made to interlock, and this had the effect of reversing the direction of rotation. Shaft 9, therefore, became the new wheel shaft; and the boat would now turn the way it should.

  The Chinese rudder: The three rows of diamond shaped holes in our rudder, traditional in Chinese junks, provoked more questions than just about anything else. People were fascinated by this curious feature. There must be a good reason for them, they think, and I am inclined to agree. Unfortunately, I have never been able to give a genuinely satisfactory explanation and I am yet to meet anyone else with good first-hand junk sailing knowledge who could.

  From our personal experience, I would observe two things. Firstly, the hole edges are a problem from the painting point of view. Small, grasping shells love them. Secondly, I was glad of the holes when our rudder was being battered by waves directly from the side, while we were hove to. Perhaps they were giving a degree of stress relief? But why are they diamond shaped, not round? Why so small?

  Many suggestions have been made to me. Manoeuvring in harbour is meant to be easier (on Tin Hau it was reasonably easy). Turning of the rudder meets with less resistance. Turbulence and stall zones are created with beneficial eddy currents. However, not having experienced Tin Hau without her ‘holey’ rudder, I can make no comment on the views offered by the experts, whether they be naval architects or aeronautical engineers. One day, I hope, the puzzle will be solved.

  The other mystery is the two inch by two inch angle welded to the four foot high trailing edge of the rudder. As we gazed at our wake and watched the bubbly, disturbed water leaving this last bit of Tin Hau’s structure, we often wondered how this might help. The angle was not just detailed on the drawings, but it was also emphasised to me as ‘extremely important’ by Tony Richardson of Southampton, the owner/b
uilder of T’ai Shan, sister ship to Tin Hau (we were lucky to ‘discover’ Tony early on during our boat building days, and we have kept in touch with him ever since).

  Rudder position indicator: At first we had no rudder position indicator and, in spite of the groove on one of the wheel spokes, it was sometimes hard to know in which direction the rudder was pointing. It was easy to think it was lying dead central, whereas really it was ten degrees off dead centre with the wheel one whole revolution to – say – starboard. Lynda solved this problem neatly by cutting a small circle of perspex with a central void that fitted over the square head of the rudder post. One segment of the perspex, made visible through a slot in the woodwork, was marked 30°, 20°, 10°, 0, 10°, 20°, 30°. As the rudder post turned, the marking on the perspex would line up with a single line drawn on the woodwork. This was all that was needed to tell us the rudder position. No electronics, no delicate needles – and hardly any expense.

  Key to Figure 10: The steering System

  1. Rudder ex 10 mm plate, stiffened horizontally. Three rows of diamond shaped holes, 50mm x 50mm andgle on trailing edge.

  2. Lower bearing. Simply a steel cup welded to the keel, machined exactly to fit the rudder post. Well greased steel disc in cup base to reduce friction. Greasing points fitted.

  3. Upper Pillar Bearing bolted to steel framework.

  4. Rudder Post ex 65mm diameter solid bar weighing 80kg. Welded (after installation) to the rudder plate

  5. Rudder Port ex 90mm OD 8mm thick pipe welded to hull and bulkhead tie.

  6. Quadrant ex 10mm steel plate with weight-reducing cut-outs; 0.6m radius. Welded to rudder post. For plan view see Figures 1 or 2.

  7. Vertical Slave Shaft ex 45mm diameter solid bar. Two pillar bearings, three gear wheels (11 teeth to the quadrant, 22 teeth to the wheel slave shaft and twenty eight teeth to autopilot slave shaft.

  8. Wheel Slave Shaft ex 25mm diameter solid bar. Two bearings, two gear wheels (11 teeth to the vertical drive shaft. 50 teeth to the wheel shaft).

  9. Wheel Shaft ex 25mm diameter solid bar. Two bearings, one gear wheel (50 teeth to the wheel slave shaft). Key-way at end for wheel. Forward end can be extended for external steering.

  10. Wooden Wheel with spokes . 0.6m outside diameter.

  11. Helmsman's Seat reduced over two years from a scond-hand draughtsmans chair with arms and tilting back to just the seat portion.

  12. Compass (Sestrel Moore) mounted high and upside down, well clear of all steelwork (to minimise magnetic problems.

  13 Rudder stops (2 No.) to prevent the quadrant (and thus the rudder) from rotating more than thirty five degrees in either direction.

  14. Emergency Tiller lashed and stored in the lazarette.

  15. Autopilot Slave Shaft ex 20mm diameter solid bar. Two bearings, two gear wheels (20 teeth to the vertical slave shaft, 44 teeth to the autohelm motor).

  16. Autohelm 6000 Motor installed eighteen months after launching.

  17. Number Seven: The name given to the two ropes that lash the wheel and thus – in some conditions – steer the boat.

  18. Rudder Indicator (perspex). Mounted on the rudder post.

  R

  efer to the previous page for the key to the various part numbers.

  10.8 the windlass and chain

  Tin Hau’s windlass has such a history to it that it is worthy of some detailed description. We do not even know where it spent its early days, probably at the top of some slipway in South Africa where it would have given years of service launching and hauling out boats. We came across it – following a tip-off from Ronnie – in one of Port Elizabeth’s more intriguing junk shops, which goes by the name of EPBuyers and Sellers . This is a place where I could easily have spent a whole day if I had ever had the time, containing rooms full of every conceivable domestic and industrial item, usually at bargain prices.

  Sitting in one corner, buried under piles of cloth, was a three foot high winch, dusty and neglected but otherwise looking in good shape. I was pleased to find it described as a ‘crab winch’ in my Simpson Lawrence catalogue, and was able to read a technical specification. The new price, I noted, was about fifty times the junk shop price. So, with some trepidation about how we would make it suitable for Tin Hau’s foredeck, we bought it.

  The first job was to strip it down, send the mild steel cheek plates for sandblasting and priming, and then reassemble it with a longer main shaft on which we would fit two chain gypsies. Also the drive shaft would need modifying and two handles welded on to each end. The aim – which we achieved – was to construct a hand operated windlass, capable of being used by one person when hauling up anchors, or by two people simultaneously. I also wanted to have an easy system for setting two anchors at the bow, each being attached at all times to about seventy metres of chain, which, when not in use, would lie unobstructed in the forepeak.

  As mentioned earlier, the problem was: what comes first, the chain or the gypsy? The local chain manufacturers did not make gypsies. And the gypsy manufacturers, who could supply chain, were abroad. There seemed little point in importing nearly half a ton of eleven millimetre chain when it could be bought for a reasonable price and to a high quality in South Africa. So we decided in the end to place an order with McKinnon Chain of Benoni.

  The problems started with the two gypsies. Simpson Lawrence in Glasgow agreed to make them to match a small sample of our chosen chain. But when it came to delivery we thought we would take advantage of the fact that Lynda’s parents were about to have a holiday in Britain and would be staying in a certain London hotel. We gave the address of the hotel to Simpson Lawrence and the estimated date of arrival of Lynda’s parents. All was going smoothly at this point; the gypsies were made on time and delivered to the hotel. However, the hotel staff took fright and thought that such a small, heavy package might be a bomb. They refused to keep it and redirected it back to Scotland.

  Thus began a long and involved correspondence concerning the whereabouts of the gypsies– but we got them in the end. They fitted the chain (more than many gypsies do!) and it all ended happily.

  10.9 the anchors

  The most commonly seen anchors on cruising yachts are the CQR, Danforth and Fisherman. These were all available – in different sizes – at yacht chandlers. But the price of the larger ones was exorbitant. Also, I was not happy with some of the well-known weaknesses (for example, the Danforth’s shank is often known to bend on being pulled excessively from the side); and I was having great difficulty in working out convenient stowage positions. Bearing all this in mind, I decided to design our own anchors, and have them made locally.

  Danforth and Northill anchors (the latter being used by Tom Colvin on Kung Fu Tse, and unfamiliar to me then) are both convenient for welded construction, and so these appeared to be the most viable choices. I liked the idea of having two different anchor types, both ready to drop at a moment’s notice.

  Taking advantage of having a drawing board at work and structural steel design books at hand, I spent many a lunch hour designing and detailing the anchors. The main factor to remember on the Danforth is that the angle between the flukes and the shank is critical. It must be about thirty-two degrees. After that, it was a matter of minimising weight where not needed and keeping the fabrication as simple as possible. Ronnie’s brother actually made our anchors, very proficiently and at a reasonable cost, a complete ‘family’ of Danforth types – fifty-six kilograms, twenty-eight kilograms and fourteen kilograms – and one single thirty kilogram Northill type. The two smaller Danforths were kept on deck as spare anchors and for stern use, the smallest one also being used at times as a very generous dinghy anchor. The largest Danforth and the Northill were stowed on the two ‘anchor cats’. Such was the efficiency of the windlass that I ended up using the heavy fifty-six kilogram Danforth as our ‘working’ anchor. Originally I had thought it would only be used in storm conditions.

  The anchor cat idea of the Chinese is, I think, a very good one (refer
to the deck layout plan in Figures 1 and 2). The anchors are securely stowed clear of the hull and overhanging the water, yet they can be dropped in seconds. On weighing anchor, once the anchor itself was clear of the water and hanging from the bow roller, I used the boat hook to reach the eye of a short length of rope permanently spliced on to a point two-thirds of the way along the anchor shank. I then led the rope over a small roller on the anchor cat, clipping the eye to a carbine hook which was kept permanently shackled to a double block through which, along with a similar block shackled to the boat a metre aft, a rope was reeved. At this stage I would turn round and pull on the end of the rope. Once the anchor crown had swung outboard tight up against the anchor cat, I would cleat off the rope on to one of the bulwark pins. The whole operation usually took thirty seconds on a good day, when no anchor washing was required.

  We had been well trained in anchoring techniques years earlier when flotilla sailing in Greece with the first flotilla company operating there, YCA (Yacht Cruising Association). They taught us how to select the best spot to drop anchor, how to drop it at the right time when moving ever so slightly astern under power, and finally, to dig it in securely with the engine for a few seconds under high revs. With Tin Hau we added a few extra rules which became standard procedure.

  First we made quite sure that both chains were well marked at ten metre intervals so we knew how much we had let out. The best marking system we found in the end– after a bad experience in Aden – was to tie brightly coloured ribbons to the chain – one ribbon denoting ten metres, two marking twenty metres, three marking thirty and so on. Every so often we would replace a tatty ribbon; mainly the ten, twenty, thirty and forty metre markers on the port chain, being the most commonly used.