Furling Gear and Trailers

Single handed Dabbing Part 3 Furling Gear and Trailers Performance I can’t help it but I race other boats when I'm in the Dabber. It happens like this. If I’m sailing down the estuary and spy a sail I will try to overtake it. The trouble is that the crew of the other vessel have no idea that it’s a race. They’re just enjoying a sail and watching the world go by while I’m working hard searching for catspaws, windshifts, wave sets and favourable eddies and making course, rig and centreboard adjustments to suit. On one occasion I remember following a reasonable sized cruiser about six miles along the coast before drawing abeam. I also remember the long beat back. It seems to me that on the Dabber there is one rig adjustment, apart from sheet trimming, which has an effect greater than any other. It’s difficult to be objective about this as you can’t detect an increase in speed of the order of tenths of a knot. My GPS shows tenths of a knot but won't be accurate to that level. You’d need initial accuracy coupled with fancy averaging to show what I’d like to see. The problem is that a boat’s speed is not constant and every variation in wind and every wave slows and accelerates the boat. It’s interesting to note that the performance difference between the earliest and the latest Flying Fifteens is reckoned to be only 40 seconds per hour. There is however, a very effective way to fine tune sailing performance and that is to race a one design. If you are alongside a boat which is identical to yours you have a reference point for relative speeds and can fine tune accordingly. I’ve never come across another Dabber while I've been sailing mine but it would be really interesting to compare them. So how do I trim the sails for best performance? I’d use tell tales but as you can’t see through Dabber sails I do it by eye, adjusting to reduce wrinkles and trying to achieve what I imagine an efficient aerofoil looks like. This will, of course, only approximate to an efficient trim but it’s all I can do. I know it’s a Dabber and I promise I’m really not obsessed with performance but I still can’t leave a sail badly set. So what is this all important rig adjustment? 1 The tack downhaul At its simplest the tack downhaul is a line attached to the mast thwart, rove through an eye (or fitting) at the tack and returning to a cleat or belaying pin. I needed to retain the ability to adjust the downhaul at the mast (crewed) and also from the steering position if single handed. The lanyard has a stainless ring spliced into one end and the other end is lead through a block attached to the mast, up through a second block which is hooked to the boom, travels down through a tubular jamming cleat and is finished with a figure of eight. Stainless ring and carbine hook. The crew can adjust the downhaul simply by utilising the tubular jammer. The stainless steel ring at the other end of the line comes up against the lower block. Without a crew a control line is attached to the stainless ring with small carbine hook and is lead back to a cleat at the after end of the centreboard case. Lower block Under certain conditions it needs quite a lot of force to reduce the creases in the main using this downhaul and the 2:1 mechanical advantage is only just enough to make it easy to operate. A cascade system with a block replacing the carbine hook makes sense and would give a 4:1 purchase. Jamming cleat 2 Furling gear Furling gear is a complication and something else to go wrong but it’s just so convenient I wouldn’t want to be without it now. There is another benefit apart from being able to furl the jib. If you can remove the original forestay then it becomes so much easier when you tack as you don’t have to drag the jib around the forestay. The Dabber, in it’s original form, has a forestay terminating at the stem head and a bowsprit with no bobstay. To set up furling gear and not to use the luff wire in the jib as a forestay seemed a bit silly so a bobstay was a must. There was not a lot of choice in attachment points with the sole option being the towing eye. In my boat this eye is 40 year old and made of brass. It needed checking. (see later) The bowsprit The Dabber jib came with a loose eye at one end of the luff wire which looped over the end of the bowsprit. There is nothing wrong with this and the original bowsprit would do the job admirably but I decided to make a new bowsprit to incorporate a proper cranse iron (mast band) to attach the rigging. I think the truth is that I liked the idea of laminating two More different coloured woods. Some of the bits and Beautiful pieces on boats are a joy to make and are bronze. lovely to look at. Having said that, it was a bad design and could really do with being replaced. The bowsprit was laminated using two pieces of softwood and one of mahogany. Moving the forestay to the end of the bowsprit, and providing a bobstay, changes the loading on the bowsprit from bending to compression. This means that the tension in the rigging pushes the bowsprit towards the stern and this force is transmitted to the mast thwart via a wooden cleat screwed to the thwart. I didn’t think that this was up to the job so replaced the cleat with a more substantial version which I modified to act as a mast crutch when trailing. It was a real pleasure to work with teak again.. 3 Setting up the furling gear required: • A wire bobstay from the towing eye to the end of the bowsprit. This is a length of 3mm stainless wire with a snap shackle at one end and a bottle screw at the other. It is important to realise that the rigging screw is only to adjust the length of the bobstay and definitely not to tension the forestay. • A furling drum attached to the end of the bowsprit. The drum is attached directly to the cranse iron. • A new forestay (luff wire) in the jib. I used the same sized wire as I used for the bobstay. • A furling line running back to a cleat amidships. • A new jib halyard. There are so many ways to rig the halyard, all with their own disadvantages, but I settled for the simplest. It’s a three fold purchase with a fiddle block attached to the mast head and rigged with braided line (three strand rope twisted too readily) leading down to the belaying pin. I’d be reluctant to use a system whereby the standing part, and the fall, terminate on the mast thwart; it’s only held down by two 1/4” brass bolts per side. Bearings I did have serious problems with furling drum and top swivel bearings in two manufacturers products. In the end I had to replace the balls in the drum with 4 mm stainless balls and replace complete bearings in the swivel with some intended for use in robotics. Rigging tension I didn’t want anything to break so some measurements and calculations were called for. “Sweating” a rope using a belaying pin can be a very effective means of tensioning a rope; I needed to find out just how effective. Using a snatch block at the mast head and another one at the end of the bowsprit I was able to lift 110 ponds below the end of the bowsprit without too much effort and without assistance from a block and tackle. Given that the jib halyard was a 3:1 purchase I would be able to tension the forestay to something like 330 pounds. (less with friction losses) The geometry of the forestay, bowsprit and bobstay means that the tension in the bobstay will be around 1.8 that of the forestay. This gives a bobstay tension of around 600 lbs. This is within the SWL of the individual components but is still a lot of tension. A halyard with a 2:1 purchase would set up the rigging tension nicely but you can be a lot more precise with a more powerful tackle as long as you are aware of the power. 4 Mast head The Dabber came with what I assume is its original masthead fitting. This was a stainless steel ring resting on a shoulder cut around the top of the mast and retained by a rather large brass split pin. Wires were spliced directly onto the ring which had, over time, mangled the top few inches of the mast. There was no alternative but to scarf in a new top to the mast and, while I was at it, I fitted another bronze mast band from Classic Marine. Bronze is such a lovely material that I’m going to buy another one to keep on the kitchen table and admire. Shrouds The shrouds were originally attached to the deadeyes with a lashing; a method which has a lot going for it.

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