Nottingham 60: J Class Radio Controlled Yacht by Alan Horne

Nottingham 60 J Class Radio controlled yacht Alan Horne 07969 538626 www.jclasshulls.co.uk Nottingham 60 Build Manual Section 1. Introduction. The Nottingham 60 has a full keeled hull designed to represent the J Class yachts of the 1920’s and 1930’s and although the silhouette of the hull may be similar to some of these yachts, it is not a scale replica of any. Even in their day, the J Class yachts were tender in stronger winds, and if the hull is scaled down (and this hull would be about 1:20) a 10 mph wind would scale back up to 200mph!! Some compromise is necessary to create a model that both looks good and sails well but | hope you will find that the model is a good representation of theJ Class design. Specifications: Overall length. 1.525 metres Beam. 260mm Draft. 255mm Ballast. 10kg Overall displacement. 14kg Overall height. 2.050 metres Sails: Foresail Mainsail Foot 510mm 770mm Luff 1320mm 1700mm Leach 1220mm 1850mm The sail control is through a single sail winch operating a fixed loop to which the loose sheeting is attached. Further optional control of the jib slot is by a separate sail arm. Sail winch Hitec HS785HB Sail arm Hitec HS765HB Rudder servo Hitec 325HB 1.1 The first step is to check your hull. Both the hull and rudder have been checked for imperfections and given a final polish and we pride ourselves in creating a hull and rudder to the highest standards. If however you find something that you are not happy with, now would be a good time to let me know! It is quite possible that both when building the model, and when using it, that you will put small scratches into the fibreglass gel coat but these can be simply removed by lightly sanding with a 1200 or 1500 grade wet and dry paper (used wet) and then polishing. The gel coat is up to 1mm thick to allow for refinishing the surface over the years as small scratches appear. 1.2. Building the model is not difficult, but the model is more complicated than the Nottingham 48 as it contains more parts. The model should be sufficiently absorbing and challenging to give you a sense of satisfaction as you build it, but you should be able to create an attractive and desirable craft when completed. It will pay dividends to measure and mark the hull where the beams fit as carefully and as accurately as possible, take your time! When building the first model | found that it was easy to put twist into the hull so after gluing each part | checked for straightness using a string line between the bow and the centre of the stern (see pics later). Twist is more easily created when gluing in the inwales as they are under tension so it is prudent to take special care at this stage. 1.3 Fibreglass can take up to a year to cure fully so if you are not going to build the model immediately | recommend storing the hull upside down with two small pieces of wood used to support the bow and the stern. This will help to keep the shape of the deckline and avoid the sides of the hull splaying out or otherwise distorting. 1.4 You may have your own favourite glues and stains however if you are unsure | use the following: a) Where wood is being fixed to fibreglass | use Devcon two part epoxy adhesive. It can be obtained in two setting speeds, 5 minute and 30 minute but the actual setting time will depend on temperature. Low temperatures will substantially extend the setting time of both so in the winter, in a cold workshop | tend to warm both parts before mixing. b) Where wood is being fixed to wood | use either the Devcon as above or an Evostick exterior grade wood adhesive. The Evostic doesn’t require mixing so is quicker to use where larger areas of wood are being joined, (eg when laying on the deck) and takes longer to go off giving more time for adjustments. c) | use standard Colouron stains for the woodwork (available from DIY stores) and Colouron Danish Oil for the deck. | personally prefer to oil, rather than varnishing the deck as it’s easier to apply and easier to maintain. Staining the top surface of the deck is not normally necessary as the Oil will add some colour when applied. d) | use a PVA sealer (available from DIY stores or builders merchants) on all woodwork, (and especially under the deck) after staining where the finish is unseen. This will protect the wood from the damp environment that can build up when the model is being used and stored. Wood that is visible is oiled or varnished. 1.5 When working on the internal woodwork | tend to dry fit as much as possible before gluing. You will need to glue in the bow and stern pieces and the inwales but | then dry fit the main beams and longitudinal runners to assess the overall fit before final fixing. Only little sanding of the beams should be necessary to cater for the curve in the hull and it will improve the final look of the deck if you try to keep to the overall width measurements as in the instructions noted later. 1.6 Preparing the hull. As the fibreglass cures in the mould it develops a waxy surface to which most glues will struggle to adhere. The inside of the hull should be thoroughly rubbed down to remove the waxy surface and create a key for the glues. The exterior gelcoat has already been given a polish but applying a good quality wax (car wax or similar) will create a barrier against the inevitable glue and stain that mysteriously transfers itself from the part to be fixed to the outside of the hull… blame the “sticky finger fairy”… but when the glue has dried it can be easily removed with a fingernail. 1.7. The wood parts are contained within a sheet of 6mm laser ply with small nibs. These will need to be cut with a sturdy, Stanley knife or similar. Don’t be tempted to press the parts out of the sheet as you will damage the surface of the ply. When the parts have been removed, lightly sand the edges to remove excess carbon that has built up from the laser. 1.8 Above all, if you are unsure about how to progress the build, or have any questions, then email me either using the address on the website, info@jclasshulls.co.uk or alan@alanhorne.co.uk Index of Parts Part Number. Description 1 Bow piece 2 1** Beam 3 2TM4 Beam 4 3 Beam 5 4 Beam 6 5° Beam (The Mid Beam) 7 6″ Beam 8 7” Beam 9 8″ Beam 10 9″ Beam 11 10″ Beam 12 Stern piece 13 King Plank 14 Upper Mast Deck 15 Mainsail sheeting post support 16 Main hatch longitudinal side runners 17 Aft hatch longitudinal side runners 18 Rear of aft hatch 19 Stern longitudinal runners 20 Rudder servo tray 21 Main servo/winch tray 22 Jib trimming servo tray 23 Rudder support tray 24 (a & b) Forward fixed loop support 25 Aft fixed loop support 26 Aft hatch temporary brace 27 Main (forward) hatch temporary brace 28 Lower mast tube support Section 2. The Stand Description The stand comprises two ends which support the keel of the hull, with the aft end designed to locate just forward of the rudder. The ends are joined by four pieces of ply which locate into the end pieces and when complete will form a reasonably robust way of supporting the model. Note: The model should be supported on its keel, and not the sides of the hull. If the weight of the model is rested on the side of the hull the hull will distort! Instructions 2.1 Cut out the nibs that retain the parts in the sheet and stain. 2.2 Usingai.5mm drill bit, make pilot holes in the tabs that locate the side pieces in the ends. | use two brass screws in each tab (total 16 in the stand) 2.3 Apply some wood glue to the tabs before locating them in the recesses in the ends and ensuring that all is square, make further pilot holes through the tabs and screw the parts together. 2.4 The completed yacht is quite heavy so | used a thicker piece of wood as a base, (see photo) to add more strength. 2.5 Place the hull on the stand with the aft of the keel just forward of the supporting end. Ensure that the hull is supported by its keel only, and that the sides of the hull do not contact the sides of the stand. If there is contact then remove material from the stand until the hull feels loose in the stand, and can move from side to side. 2.6 | found that the hull wanted to slide further back in the stand until it was stopped by the sides of the hull making contact with the stand. To stop this | placed a small piece of wood along the base of the stand to give further support to the keel at its base. (See pic) Section 3. Fitting the Rudder. Description The rudder is a one piece laminated construction with a foam inner core which both adds strength and reduced weight. The rudder is fixed to the hull using a brass rudder tube which is supported at its base but a small brass plate epoxied into the hull. The small brass plate is tapped to take a 4mm brass bolt which fits into the rudder tube allowing it to pivot. The top of the tube fits into a wider brass tube fixed into the hull and then supported in the upper tube by a brass bush. A rubber “O” ring is pressed into the upper tube and this makes the fitting watertight. The rudder is easily removed for servicing as the upper tube has clearance allowing the rudder to be moved to the side when the 4mm bolt is unscrewed. The rudder is operated by a rudder arm connected to the rudder servo with ball joints to allow for the articulation required and the rudder arm also locates the top bush at the top of the upper rudder tube. The finished yacht is sensitive to rudder movement and only smaller movements of the rudder are required to steer the craft. The final movement of the rudder will be about 35 degrees each way but in practise the boat will steer well with less than this an if you have a programmable transmitter you may find it advisable that you adjust the speed of the rudder, and also the total movement. Instructions 3.1 The inner rudder tube has an external diameter of 4.7mm and sits about 2.5mm from the front of the rudder. It’s worth checking this as the rudder is handmade and distances may vary. The objective is for the leading edge of the rudder to lie parallel to the trailing edge of the keel with a gap of about 1mm. Using these measurements it follows that the hole required in the hull to take the upper rudder tube should have a centre about 6mm from the keel line. In practise | start with a small pilot hole in the hull about 5mm from the keel line as | find that the back of the hole opens out more quickly than the front. 3.2 Mask the area to be drilled as this will help protect the gel coat and make a mark about 5mm from the keel line and start drilling…you will feel the tension in the air!! 3.3. The upper rudder tube has an external diameter of 8.8mm but as it sits in the hull at an angle your finished hole will be oval. | use a maximum drill bit of 6mm to create a round hole and then use a file at the same angle as the keel line to open the hole up to the required oval shape. The front of the oval hole will be at the back of the keel. 3.4 Work slowly and gently to avoid damaging the gel coat but some minor damage is inevitable. Regularly check the shape, size and angle of the hole using the piece of upper rudder tube. 3.5 When the hole is complete, and you’ve relaxed a bit, cut the upper rudder tube so that its angle suits the hull. 3.6 Atthe bottom of the keel you will see two raised marks, one on each side of the keel. Using a junior hacksaw carefully cut a slot into the keel and open it with a thin file to take the lower rudder pivot. Cut slowly and carefully to avoid chipping the gel coat. The cut should extend into the hull sufficiently so that when the lower pivot is inserted the centre of the tapping is about 5.5 to 6mm from the keel. 3.7. You will need to trim the brass tube from the bottom of the rudder, leaving about 1mm protruding, and also to use a 4mm drill bit by hand, remove excess wax from the inside of the tube. 10 3.8 When you are happy with the loose fitting of the rudder, glue the lower pivot and upper rudder tube into place. | use the rudder itself to ensure correct alignment but you could use any suitable tube. It will help if you slide the rubber “O” ring to the bottom of the upper rudder tube and then use the bush to support the top. You may also feel more comfortable with the upper tube held in place (the rubber “O” ring help to stop things moving around at the top) to glue in the lower pivot and after it has set, to glue in the upper tube. 3.9 If you are using Devcon Epoxy, you can add white colour to it which will avoid seeing the less attractive epoxy as it yellows in time. | use a fibreglass pigment as | have it to hand but | understand that chalk works well. This mix can then be use to disguise any chips that have developed in the gel coat at both the top and bottom of the keel. 3.10 Add more epoxy to the lower pivot from inside the hull to ensure that the hull is watertight when it is immersed in water and the ballast is fitted. 3.11 Et, Viola…as we say in Nottingham…That’s the most challenging bit done. The rest is…dare | say…plain sailing! 11 Section 4. The ballast. Description The front of the keel of the Nottingham 60 is shaped into a bulb which allows more weight to be carried, both lower in the boat and slightly forward. This improves the sailing characteristics of the yacht but means that a moulded lead ballast can’t be used and so lead shot is the better alternative. The disadvantage of lead shot is that it is not as dense as a moulded weight but | did some experiments with lead shot, comparing the volumes of a moulded weight and the same weight of shot when immersed in water and found that when very small shot was used that the difference in volumes was less than 10% which is acceptable. | use very small reclaimed lead shot (less than Imm in diameter) and have found it relatively inexpensive but some work is needed to clean it up before using it. You will need about 10kg. The lead shot is retained in the keel using fibreglass resin but it is very important that the keel is immersed in water as the resin cures with heat and this will damage the gel coat finish if too much heat is created. It’s important to use a “cool” mix and | suggest using less than 1% catalyst, about 4% to %% is ideal. Only use small amounts and | suggest pouring in no more than 30 grams at a time and waiting for it to go off before adding more. | found that when | poured in the first 100 grams that it was sufficient to bind the shot together and the second pour of less than 50 grams created a seal on the top. When finished, the shot should be laying reasonably level in the bottom of the hull but there should be a “sheer” at the deck line, when measured at the mast position, of about 2 degrees. 12 Instructions. 4.1 With the hull floating in water, pour in at least 9.5kg of dry lead shot. Tamp the dry shot down so it is level and check the waterline. The waterline on the hull should be parallel with the water but the boat should be sitting slightly higher, to take account of the additional weight that the boat will accumulate as you build it up. Pour in the additional shot if you feel the hull should sit lower in the water. 4.2 A second check for those with a two tone hull, and the primary check if you have a hull ina single colour is to check the sheer on the deck line at the mast position. This should be about 2 degrees, (+/- % degree) 4.3. Just to make sure… a third check is that the bow should be about 130mm out of the water and the stern about 70mm out of the water. 4.4 Using 100 grams of resin make a “cold” mix using between 4% and %% catalyst. Pour in half of the mix and using some waste wood, lightly tamp the shot down. Pour in the other half and repeat. Recheck the levels of the hull in the water. 4.4 This mix will take some time to go off and | suggest that you leave the hull in the water to keep the gel coat cool overnight. 4.5 When the first mix has set, make a second mix of 50 grams of resin and float it over the top to make a seal. 13 Section 5. Internal woodwork. Description The internal woodwork is all in 6mm laser ply and serves to add strength and rigidity to the hull. The beams, and servo trays strengthen the hull on the horizontal plane and the mast tube adds vertical rigidity to the hull ensuring that all the power from the sails is passed to the hull and is not absorbed by flex in the hull structure. The biggest problem that the modeller will experience is twist in the hull as the woodwork is fitted. It would make sense to re-check the hull for straightness at each stage by passing a straight edge from the stern to the bow. | use a length of string with a light weight that can be moved along it (piece of brass or aluminium tube) as this can be slackened to reflect the curved shape of the deck line. The time to take the greatest care is when gluing in the inwales as after this, as the beams are laser cut to very fine tolerances, twist becomes less likely. Laser ply is a special plywood which uses a glue that doesn’t burn, so leaving a cleaned edge, with significantly less carbon deposit than a normal plywood however it is considered to be an “internal ply” so it will need to be sealed to protect it from water/humidity. | stain the parts first, and when fitted (but this can be done before gluing) | coat the parts that are not seen in PVA and the parts that are visible with the hatches removed in exterior grade waterproof oil as this gives a more attractive finish. There will be a dusty carbon edge where the laser has made its cut and this can be removed by light sanding. It’s only necessary to remove the dusty deposit to promote good adhesion from the glue, it’s not necessary to remove the blackening back to white ply. A further note is that if you glue in the main servo/winch tray before the beams, there is a risk that the hull will open up, but, the tray is too big to position through the beams after they have been glued in so | left the tray loose in the bottom of the hull until the bulk of the beams were fitted and then glued in the trays. The beams have been measured and cut at specific widths so that the outer plank of the deck is of a similar width along its length which will make the finished model more pleasing on the eye. Try to avoid reducing the overall width of the beams when sanding although you might want to chamfer the ends to match the curvature of the hull. The parts are held to the sheet by small nibs which will need to be cut with a sturdy craft knife. Cut from both sides of the sheet and don’t be tempted to press the parts out as this will damage the surface of the ply. 14 Instructions 5.1 Remove parts Nol and No12, the bow and stern pieces. The stern piece will need some shaping to its lower edge for a good fit. Both parts will need some shaping to take ends of the inwales. Glue in the parts and it will be useful later if the etched line is in the centre of the hull. 5.2 Measure and cut the inwales to size. It is better if they are slightly short, rather than long as a longer length than required will have the effect of pushing out the side of the hull when fitted. | dry fit the inwales first and then measure the width at the mid-point to ensure that the tension created by bending the inwales is not creating distortion in the fibreglass of the hull. Note: All the woodwork, including the inwales, should fit slightly lower than the height of the top of the hull. This will simplify fitting the deck and ensure a good seal between the top of the hull and the deck. If the inwales are fitted about %mm to 1mm below the top of the hull, all the other parts should sit at a similar height. 5.3 The inwales can then be glued in. | use the longer setting epoxy which gives me time to apply the glue, and make adjustments if necessary. 5.4 | use pegs and grips to retain the inwales as the glue sets. | found that using a second piece of wood to sandwich the hull avoided rippling the fibreglass where the pegs applied pressure. 15 5.5 Find and mark the mid-point of the edges of the hull. It will be useful if this mark is as accurate as possible as when the mid-beam (No 6) is fitted, it will determine the position of all the other beams. | measure a straight line from the bow and start by making a mark at 781mm from the tip of the bow. If you then place a straight edge (ruler or similar) across the hull at the marks, the measurement from the bow to the middle of the ruler should be 770mm. Trim the beam so that the top of the beam is at the same level as the top of the inwale. 5.6 To find the optimum position for the mid-beam No 6, remove the beam No 8 from the sheet, and the two longitudinal runners No 16 and dry fit. Adjust the beams so that the hatch opening is square, ie that the corners are all at 90 degrees, check that the middle of the beam No 6 is 770mm from the bow (767mm when measured from the front of the beam to account for its thickness) and mark the edge of the hull accordingly. Be patient, it’s worth getting this bit right! Note that all the beams are at 125mm apart at their centres. 5.7 When you are happy with your marks for the two beams, it’s time to deal with the two servo trays. The position for the main servo/winch tray is not critical however | suggest that it fit so that the two screws retaining the forward part of the servo are accessible from the hatch. If the servo fails it will be easier to remove and replace. Make a mark on the edge of the servo tray approximately 230mm from the front of the tray and a second mark on the inner hull vertically down from the mid beam mark. This will give you a rough position for the tray. 5.8 The main servo tray and the rudder tray support the fixed sheeting loop. Part No 25 should be screwed to the rudder tray on the mark etched on the tray and one of parts No 24a, or 24b should be screwed to the main servo tray. 24a and 24b are the same but have different heights. If you fit 24b, and are using a Hitec winch, the top pulley on the sheeting loop will line up with the top drum of the winch. If you are using a Hitec winch, mark a line parallel to and 15mm from the edge of the servo cut out and screw 24b to this line. In theory at least… when the rudder tray and main sheet tray are fitted, parts no 24b and 25 should line up! 16 5.9 | chamfer the edge of the tray to improve the fit in the hull and to take account of any variations in the hull and trial fit with the two beams, parts no 6, and 8 in place. Try to avoid removing too much material as this will lower the tray in the hull and it won’t line up with the rudder tray…. 5.10 …Take the rudder support tray and chamfer the same. You will need to remove more material from the rear of the rudder support as the hull has a shallower angle at this point 5.11 Dry fit the main servo tray and rudder support tray and use a straight edge to check for fit. Note that | have dry the mid beam when trial fitting the servo tray otherwise the main servo tray will tend to drop in the hull, opening the sides up. Mark the positions for future reference 17 5.12 Now dry fit the jib trimmer tray (if you are using one). Trial fit with a servo in place as this tray is offset and if fitted too low in the hull the bottom of the servo will foul the hull. The position of this tray is not critical but ensure that the arm of the jib trimmer servo doesn’t foul the bottom of the main winch servo. Mark the position for future reference. 5.13 Now would be a good time to double check the hull for straightness. | had inadvertently put some twist into the hull when | fitted the inwales (see photo). | think that this was because one inwale was slightly too long and a tight fit to the bow and stern piece. This put pressure on the side of the hull, pushing it out a bit. (In the photo, the right hand inwale.) 5.14 The answer was to use a piece of scrap 6mm wood, cut to the right length, to apply pressure on the other side to push the hull back to shape. Where ever possible after this, and when finally gluing in the beams | retained this brace in the hull. (Note the position of the line before and after the brace is fitted in the above pics.) 5.15 Now the bit you’ve been waiting for, you can glue in the parts. Start with the main winch tray and the rudder support tray. Use the straight edge to ensure that the fixed loop supports line up and also position a couple of beams to stop the hull opening up. When the glue has dried, the main winch tray will significantly strengthen the sides of the hull so if you’ve found the need to use a brace to straighten a twist, ensure it remains fitted until the glue has dried. When dry, glue in the jib trimmer tray. 5.16. | started with the mid beam and worked aft. When each beam was fitted, | double checked the widths against the measurements listed at the end of this section. The closer you can get to these measurements, the better and more uniform the outer plank will look on the finished model. Also ensure that no part fits higher than the top of the deck line. | have small spacers (washers to anyone else!) that | use to ensure that the parts are slightly lower than the deck line. 5.17 | started with the mid beam, No 6, and the rear main hatch beam, No 8 and glued these parts in together with the longitudinal runners, No 16. | re-checked to ensure that the hatch aperture was square. 18 Note: Before fitting the beam which forms the rear of the hatch | screwed in two small brass hooks at the point where the beam and the runner meet. These hooks will be used to retain an elastic band to keep the main hatch secure, and also to locate a single pulley for the jib. When dry | glued in No 9, front of aft hatch beam and No 11, the final beam aft once again with the longitudinal runners No 17. 5.18 The final stern runners, No 19, will be too long and will need to be cut to fit before being glued in. 5.19 Part No 18, the rear of the aft hatch can now be fitted. 5.20 When the glue has set, you can now fit the short beam sections, Numbers 7 and 10. When fitting these, use the braces 27 and 28 to retain the shape of the hatch. 5.21 It is prudent to check the hull for straightness as you go, check that the beams are below the deck line and also check the widths at the beams. If everything is going to plan, all the beams should be a “light fit”, by this | mean if the boat is tapped lightly, the part will drop out. If you find that something is either tight or too loose, you will need to identify the cause first as removing material from one beam will have an impact on all the others! 5.22 When the rear of the model is finished, you can deal with the front. This is much simpler however is will save time of the holes for the mast tube are made in part numbers 14 and 28 first. The centre of the mast tube should lie between the slots of part 14 where the two side beams, No 5 fit. Do not glue in part no 28 yet. 5.23 | found it easier to screw the beam No 4 to the upper mast deck, No 14 before final fitting and fit both parts together. Drill a 2mm hole where at the centres etched on the beam No 5. 5.24 The king plank, No 13, is too long and will need to be cut before fitting. After this is fitted and the glue has dried you can fit the beams No 3 and No 2 noting that all the beams are at 125mm centres. Once again, check the widths and that none of the woodwork is higher than the top of the hull. 5.25 The final parts, No 15, the mainsail sheeting post support can be fitted. (note the etched mark for drilling a 6mm hole to take the post) No 20, the rudder servo tray can be fitted. 19 The Mast tube | supply an oval mast tube which can be used, in conjunction with the mast ram, to adjust the rake of the mast to suit different wind conditions. This is used by racing boats but you may find it unnecessary for the Nottingham 60. If this is the case, a round brass tube with an inner diameter to suit the mast can fitted in the same way as the oval tube. Remember to seal the bottom of the tube so that water cannot get into the hull! If using the oval tube, you will need to make a pin of about 3mm diameter that fits across the mast tube, about 120mm down and make a similar notch across the base of the mast. The mast will pivot in the pin and this does also have the advantage that the mast cannot rotate within the tube as the boom swings. The tube is fitted so that the mast stands vertically when viewed forward to stern and when viewed from the side, the boom (at right angles to the mast) lies parallel to the deck. | fit the tube with the hull floating in water, a shorter “slave” mast located in the tube and parallel to it, and a plum line as a gauge to ensure that the mast is vertical when viewed from the bow or stern, and a 90 degree angle attached to the slave resting on a spacer (20mm wood blocks) next to the mast, and also on the stern. When | am happy with the position, | glue the mast at the mast deck, and onto the ballast and when this has set the final operation is to glue in the lower mast support No 28. Fixing the mast tube at three points adds significant rigidity to the hull ensuring no flex as the model is driven forward by the wind. 20 Measurements at the beams Beam Part No Width across hull Measurement from the mid beam Bow 1 69 625 1st 2 122 500 2nd 3 172 375 3″ 4 211 250 qth 5 (mast) 239 125 5th 6(mid beam) 255 @) 6th 7 259 125 7 8 250 250 gin 9 227 375 gth 10 188 500 10% 11 133 625 Measurements across the hull should be as close as possible to these measurements above. Note that due to the curve of the hull that if the beam is slightly out of position then the width can vary quite a lot. It’s perhaps more important that the beams have a snug, or light fit, without having to remove or add material. If you achieve the measurements to a tolerance of + or — 1mm or so the outer plank of the deck will run parallel to the eye with the edge of the deck. If you’re measurements are out, the outer plank may appear to vary in width but this will have no impact on the sailing qualities of the boat, it’s purely aesthetic and can ultimately be disguised! 21 Section 6. The sheeting loop. Description The winch turns a fixed sheeting loop to which the loose sheeting to the sails is attached. No elastic or other means of tension is required in the fixed sheet loop as the loose sheeting is pulled by the sails in the same horizontal plane as the fixed sheeting loop and so the sheeting cannot be pulled off the servo drum. The fixed sheeting loop runs round two pulleys located at each end of a length of aluminium channel secured onto the main winch tray and the rudder support tray. The loose sheeting is attached to the fixed loop and then runs parallel to the fixed loop to a further pulley at the ends of the aluminium channel before going to the sails. The jib sheet then passes through the arm of a trimming servo which can be moved independently of the main winch allowing the jib slot to be adjusted while the model is in the water. The jib sheet is also passed through a small brass tube with one end located in the forward hatch, and the other just above the deck, within the fairlead which makes access simpler with the deck fitted. The system is simple and robust and should provide reliable service over a long period. Instructions 6.1 The 8mm aluminium channel has an internal measurement of 6mm and should be a snug fit over the fixed loop supports (24 and 25). The fixed loop support No 24 is cut out at the top to allow space for the nuts that retain the forward fixed loop pulley. The aft pulley fits to the rear of the fixed loop support No 25. Mark and drill the channel accordingly to take the two pulleys. 22 6.2 You will need to fabricate a small bracket as shown in the picture to take the pulley which is positioned to the side of the channel and which both directs the fixed loop back to the lower drum, and which also takes the loose main sail sheet. 6.3 At the aft end of the channel drill and fit the final pulley to the other side (The main sheet runs to the inside of the channel and the jib sheet to the outside.) This pulley is fitted slightly forward of the fixed loop pulley (see pic) 23 6.4 The channel is then fitted over the fixed loop supports. Check that the forward fixed sheet pulley lines up with the upper part of the servo drum, and the pulley fitted to the bracket lines up with the lower servo drum. (Note that my bracket is fitted a little too close to the servo so I’ve had to remove a small amount of material to allow me to conveniently remove the servo if necessary.) 6.5 The arm of the jib trimmer servo requires extending. | fabricated an extension from aluminium bar with the length of the arm 85mm from the turning point of the servo. 24 Section 7. The Deck. Note: If you are using my hatch pack, the aluminium angle, used to form the combing, needs to be fitted before the deck is fitted! Description. The deck is produced from 1.5mm birch ply with planking detail etched by laser. The etch is a carbon deposit and if the deck is sanded this detail will be lost. The material is thin and easily warps so before fitting the deck should be stored flat, with something on top to avoid the wood absorbing moisture from the air and deforming. Some slight warping cannot be avoided but if larger warps appear the deck can be flattened by wetting the surface (with a fine mist spray) and laying flat. There are cut-outs for the hatches but they are deliberately made small to allow for individual builds. You will likely need to open them up by between 1mm and 2mm at each edge and | suggest a sharp and sturdy craft knife run along the edge of a metal ruler. Use light passes with the knife and start from each corner and work to the middle. It’s very easy for the knife to slip, and cut into the deck further than you intended. The deck is designed to sit on top of the edge of the hull so that when finished the edge of the deck is visible and not the edge of the fibreglass. It is possible to stain the deck in different colours but the risk of stain bleeding along the grain of the wood is high! You will see from the pics that I’ve had a go and the finished deck looks good. If you choose to follow me, use the etch lines from the laser as a guide to cut through the top layer of ply and down to the glue and then scrape the gap a bit wider using the tip if a small file. This gap will act as a barrier and restrict the opportunity for the stain to bleed across the grain. | finish my decks using an exterior grade clear oil, Coloron Danish oil or similar. | don’t usually stain the deck as the oil will take the colour a couple of shades darker. | apply a reasonable generous first layer with a brush and when it has had an opportunity to soak in (10 mimutes or so) | wipe off the excess with a lint free cloth. Subsequent layers of the oil are applied more thinly. Anticipate a minimum of four coats. 25 Instructions. 7.1 Before fitting the deck ensure that the interior of the hull is complete as access is limited! Also check that there is no internal woodwork which is proud of the edge of the hull. If woodwork sits proud of the hull line it will be more difficult to seal the deck and the finish won’t be as attractive. 7.2 If you are using my hatch kit, you should now fit the aluminium combing. | used small screws to fix the combing, ensuring that they fit squarely over the hatch openings and are also central to the hull. 7.3 | attach my hatches using small brass pins at the front of the hatch which fit through holes drilled in the combing and if you want to copy this, now is the time to drill the holes. The back of the hatch is held with elastic. 7.4 The openings for the hatches are made slightly small and will need to be enlarged for the deck to fit over the combing. | use a sharp knife and make a number of lighter cuts into the wood using a ruler to ensure the cut is straight. Be wary at this stage as the knife can be “gripped” by the adhesive in the plywood making the cut difficult to control. 7.5 You will need to mark and drill/cut for the mast tube, jib fairlead and mainsail fairlead. 26 7.6 | also align the deck using pins at the bow and stern. Measuring half way across the hull, | drill into the king plank and then make a similar hole in the middle of the etched king plank on the deck. The drill bit can then be passed through each drilling which will centralise the deck over the hull. | then do the same at the stern. 7.7 With the deck firmly supported on the hull and in its fitting position | then make a mark on the underside of the overlap about 2mm from the edge of the hull and cut the deck to this mark. The overlap is then sanded back to the hull when the deck is fitted and the glue has dried. 7.8 As a double check, | measure the width of the outside plank on both sides of the boat so satisfy myself that they are roughly the same. It’s unlikely that both outside planks will be perfectly parallel to the edge of the hull, and also the same! Variations of up to 1 to 2mm are acceptable, and when the deck fittings are added, a small variation is not visible to the eye. 7.8 | seal the underside of the deck using a brushed on PVA sealer. This both seals the underside of the deck from moisture that accumulates inside the hull and which can blacken the ply, and also acts as a primer for the glues. A ratio of about 5 parts water to 1 part PVA will be sufficient. As the PVA is taken into the wood, the deck will try to warp so dry flat. Allow to dry overnight. 27 7.9 You are now ready to fit the deck. This is a tense time so ensure that you are properly prepared, that the deck dry fits well, and that your materials are to hand. | used to use epoxy glues where fibreglass joins to wood and exterior grade ready mixed wood glue where wood joins to wood. | have found that the epoxy sets too quickly and | find myself having to rush which this is a bad thing! | now use one of the waterproof sealer/glues applied from a gun applicator where the deck meets the hull and the aluminium of the combing, and wood glue as before where the deck joins to the inner frames. 7.10 Using the gun applicator | run a sizeable bead of sealer/glue into the channel where the inwale meets the fibreglass of the hull and also over the horizontal edge of the combing. As the deck is pressed down, the idea is that a bead of sealer/glue will be squeezed out and provided there is a solid bead all round the deck and the combing I’m satisfied that | will have made a good seal. Too much sealer is better than too little as it’s easy to remove excess when its set, but adding more when the deck is fitted is very difficult! | then run wood glue over the top edges of the inner frames paying closer attention to the areas around the fairlead frillings and the mast tube. 28 7.10 Gently press the deck to the outer edge of the hull by applying pressure and running your finger down the outside edge of the deck and along the hatch combing. You will need to do this a couple of times until you note that no more excess sealer is being squeezed out of the joint….try to avoid betting sealer on your finger and then on the deck as its very difficult to remove!! 7.11 | then apply weight to the deck as evenly as possible and then the hardest thing to do is to walk away while the sealer sets! 7.11 When the sealer has set, and this normally takes at least 12 hours, run a sharp knife along the edge of the hull, and remove the excess bead of sealer. Cut up, into the overlap of the deck, as close to the hull as possible but avoid cutting into the fibreglass. Do the same around the combing. 7.12 This will leave a small flange around the hull which now needs to be removed. 7.13. When you are sure the sealer is well cured, is to sand the edge of the deck back to the hull using a Sandpaper on a block to create an even curve. Hold the block vertically and when you see the sandpaper marking the masking tape it’s time to go more carefully. 7.14. As you can see from the photo, I’m brave enough to use a power tool to speed things up a bit. Nevertheless, | still finish the edge with a very fine sandpaper as if this marks the gelcoat, it’s easy to polish out. This tool is has a vibrating action and so material is removed in a slow and controlled manner. If you keep the too;, or your sanding block at 90 degrees to the deck you should be able to achieve a flush finish to the deck with only few minor scratches which you can polish out in the final process. 30 7.15 The finished deck! Note. You will have observed that | have stained the outer plank and king plank a darker shade, to contrast with the inner planks. There is a very considerable risk that the stain will bleed across into the inner area and this was a bit of an experiment. If you look closely you will see that some stain has bled into the inner plank area but overall | was happy with the result as, after oiling, the areas where bleeding has occurred are not obvious. If you want to have a go…. You will need to increase the depth of the laser cut that defines the outer plank and king plank cutting down through the top layer of ply and into the glue beneath. You can use a knife but I’m not sure that the “break” will be wide enough, | used the end of a round file that was a bit blunt and allowed the tip to follow the laser cut. | then used an architects drawing pen to emphasise the black line and used a pencil to increase the definition of the remaining inner planks. If you do have a go, do it before fixing the deck to the boat. If it goes badly wrong and you are not happy with the result then get in touch with me and | will let you have another deck at a reduced price! 31 Caring for your hull. Your hull and rudder are handmade and hand finished to the highest possible standards but it’s inevitable that both whilst the model is being built, and also then being used that you will acquire some minor scratches. White hulls tend to be more forgiving than hulls with a darker colour, the scratches are still there, but less visible. The gelcoat is up to about 1mm thick and surface repairs can be made by using a fine wet and dry emery paper. If the scratch is a bit deeper start with 1200 grade and then move to 1500 grade but is the scratch is more superficial, go straight to the 1500 grade. Use the emery paper wet and work slowly to remove the scratch. | also use a small sanding block as holding the paper in your fingers can result in a rippling effect. When the sanding operation is complete you will be left with a matt finish which can be polished up with a fine polishing compound, T Cut or similar and then the area can be treated to a wax to finish off. If your hull sustains greater damage in use, all is not lost as most damage can be repaired, even chips out of the gelcoat. Send me a picture by email and | will advise accordingly. Once a year, or as necessary, | give my hulls a good coat of good quality wax. The car waxes that contain a proportion of Carnauba wax work well. | also find that the deck needs a freshening up with a new coat of oil every two years or so. Every two to three years it would be sensible to remove the rudder and refit the rubber “o” ring with fresh Vaseline. If the “O” ring looks a bit tired, or perished, it would be sensible to replace it with a new one. Send me an email with your address and | will send you a new one free of charge. Should you have any questions then get in touch: www.alanhorne.co.uk 32