The Model Yacht: Volume 10, Number 2 – Fall 2006

Reprinted From: LINCOLN MEMORIAL POOL, WASHINGTON, DC NEWSLETTER OF THE U.S. VINTAGE MODEL YACHT GROUP VOLUME TEN, NUMBER TWO Fall 2006 Page 1 Editor’s Welcome e’ve got what we think is a terrific issue this time, even if we’re a couple of weeks late. At least we have a good excuse — we were sailing, first at San Francisco and then Spring Lake. We have our usual mix of news and technical material this time. Steve Crewes reports on Vintage happenings in Australia and New Zealand and Mark Steele contributes his regular “Windling World” column, highlighting some great sailing models. Kenneth Hall describes building a boat from our Sea Gull plans and we continue our treatment of plank on frame construction with an article from the United Kingdom published in the 1950’s. Al Suydam has provided a first draft for comments of our proposed V36 class rules. This effort is a particular favorite of mine because it produces a boat that is easily transportable by air. I’ve been doing this for years, and since we are scattered all over the world I hope the V36 idea will enable more of us to come to the various regattas we hold. Our next issue will, as always for the Winter issue, cover construction. I hope to have an article on modern cold-molded construction and hints and tips on making a boat suitable for shipping as checked baggage. Earl Boebert Ebbs and Flows The President’s Message Vintage Membership he VMYG annual membership is $20 for three issues of our newsletter – “The Model Yacht”. It is $25 for members outside the US. The VMYG lifetime membership is $100. Members also have access to technical assistance and vintage model plans. To subscribe to or renew our newsletter and services, send $20 or $25 check (payable to US VMYG) or cash ($100 life membership) to: John Snow, c/o US VMYG, 78 East Orchard Street, Marblehead, MA 01945. For detailed information, you can call me directly in Marblehead @781-631-4203 or visit the VMYG Web Page at: www.usvmyg.org 2006 VMYG National Events The 2006 Traditional Water Craft event was held at the Calvert Maritime Museum, MD September 22-24. I would again like to extend my personal appreciation to Buck McClellan and Solomons Island Model Boat Club for their hosting of this event on short notice. The VMYG nationals at Spring Lake, NJ was hosted by The Marbleheaders of Spring Lake on Columbus Day weekend; our thanks to John Henson and the Marbleheaders of Spring Lake for another well-run event. Both these events will be covered in the next issue of The Model Yacht. 2007 VMYG National Events The VM regatta will likely be August at Redd’s Pond, Marblehead, to help the Marblehead Model Yacht Club commemorate the 75th anniversary (1932) of the M 50/800 design being sanctioned as the second US Page 2 model yacht class. This was done by the Model Yacht Racing Association of America (MYRAA). It will include free-sail and R/C VM racing over three days. Contact John Snow for more details in early December at 781-631-4203 or jsnow@drc.com Note: The venue/date for the 2007 Traditional Sailing Craft/Scale regatta is up for grabs at this time. If you are interested in hosting it, contact the VMYG Traditional Sailing Craft/Scale Coordinator John Atwood at 757-596-9701 or john.atwood@tea.army.mil 2007 UK/US International Challenge Cup The 2007 UK/US International Challenge Cup is held every two years for 36 Restricted (36R) Class free-sailed models. In 2007, it will be on two weekends at historic sites in California: June 2 & 3 at Spreckles Lake, Golden Gate Park, in San Francisco, and June 9 & 10 at Mission Bay Model Yacht Lagoon in San Diego. Check the Winter newsletter issue for more details on this truly unique international event involving teams of US and UK F/S skippers. Contact Mike Stobbe, mwstobbe@comcast.net for San Francisco information and Ernie Mortensen, erniejm@mindspring.com for San Diego details. Other 2007 Events It is expected the US VMYG will exhibit and perform R/C sailing demonstrations at the 2007 WoodenBoat Show, June at the Mystic Seaport Museum, CT. In addition, we’ll be at the Woods Hole Model Boat Show on April 14 and 15. with a large indoor exhibit, and a R/C model yacht regatta on Eel Pond. Free Sailing Etcetera San Diego V36 Free-Sailing – The San Diego Argonauts MYC have been developing a 36 Restricted Class model group for Free Sail racing. Ernie Mortensen, Club Secretary, is the lead for this activity at 858-729-0084 or Free Sailing Vane Gears – Earl Boebert has developed a vane steering gear for free-sailing using modern materials. Prototypes have (or will be) tested at San Diego and by the UK VMYG. Check with Earl when production versions will be available for purchase by VMYG members. John Snow V36 Class Notes he 2006 U. S. Vintage Model Yacht Group National Regatta is now history. The V36 class was strongly represented with 10 boats registered. Compare that figure to the Traditional VM class which has been in existence since 1995 with 12 entered. We had five designs represented with the majority being the local Spring Lake V36’s designed and built by Pete Peterson. There were also two new V36’s from the building board of Joe Cieri – those being Joe’s own design as a modification of the Starlet design with round bilge hulls with fin and bulb keels and spade rudders, Earl Boebert brought his Yankee III all the way from Albuquerque, New Mexico, Dave Querin sailed his John Black Starlet, and I sailed my Chico II. There was quite a wide diversity of designs being sailed and because we are getting more skippers thinking about building a V36, I figure now is the time to strengthen and tighten up the V36 rules to ensure we keep the class true to the vintage spirit. With the help of Joe Cieri and Earl Boebert, I am offering the following proposal for the V36 class for the 2007 and beyond seasons: Design Formula A sloop-rigged monohull model sailing yacht with an overall length of 36 inches plus or minus a quarter of an inch. Total sail area shall not exceed 600 square inches. erniejm@mindspring.com A free sailing race with San Diego and San Francisco skippers is scheduled for November 19 of this year. Page 3 Prohibited: •Sliding or adjustable keels •Centerboards •Leeboards •Bilge-boards •Bowsprits •Overhanging rudders Bumpers shall not be included in the overall measurement. •Outriggers, pontoons, or twin hulls •Movable or shifting ballasts •Prognathous keels (no portion of the leading edge of the keel appendage, including the lead, may project forward of any portion of the leading edge above) •Metal fin keels •Materials with density greater than lead •Carbon fiber or Kevlar in the hull, rudder, rig, or keel •Fabric or film on decks 9. Rudders shall be keel or skeg mounted in keeping with the design methods of this period. It is permited to enlarge the area of the rudder from its original size in order to achieve acceptable steering with radio control. The skeg must be at least 50% of the rudder area when the rudder is skeg mounted. Balanced spade rudders are not allowed. It is forbidden to change rudders during a race or series of races except in bona fide cases of damage. Rig •Mylar sails 1. Bermuda, Marconi, Jib-headed mainsail, Gaff, Gunter, Wishbone, etc. may be used. •Swing rigs Hull Construction and materials: Hull shall be primarily constructed by the methods and materials of the period as follows: 1. Hulls shall be constructed of wood including plank-on frame, horizontal lifts, vertical lifts, or laid-up fiberglass. Molded fiberglass hulls shall be comparable to a wood-constructed hull from the same design plan. 2. Alternate rigs are allowed, provided the total sail area does not exceed 600 square inches. Details of such rigs must be comparable to the original sail plan. 3. The height of the jib head stay above the deck shall not exceed 80 percent of the height of the head of the mainsail above the deck. 2. Fiberglass covering of wood permitted as a method of sealing and strengthening the basic wooden hull. 4. Masts and boom shall be constructed from material of the period, namely wood or aluminum. 3. Modern adhesives are allowed to produce a stronger hull that is impervious to leaks 5. The height of the mast above the deck shall not exceed 65 inches. The greatest diameter of mast and spars is limited to three quarters of an inch. 4. Hull shape and configuration: there are no restrictions on load waterline length, beam, freeboard, or tumblehome. 5. Maximum draft shall be 11 inches on a model yacht fully rigged and ready to sail. Minimum keel chord length shall be four inches. 6. Total ballast must be fixed and shall not be changed during a race or series of races. 7. Minimum model weight as sailed shall be 8 pounds. 8. Bumpers are mandatory and are limited to one-half inch overhang. Page 4 6. Sail area measurement shall be the same as the VM class and can not exceed 600 square inches in total area. 7. Sails shall be made of either single panel or multi-panel sail cloth. 8. The body of each sail shall be made of woven cloth, such as cotton, cotton/ synthetic blend, Dacron, or Nylon. No material other than woven sail cloth is allowed for tablings or corner reinforcements in the head tack or clew of any sail except reinforcing tape. 9. Roach of the jib shall not exceed 1 inch, roach of the main shall not exceed 1 ½ inch. Rounded foot of loosefooted sails shall not exceed one inch. 10. Mainsail battens shall not exceed four in number and four inches in length, and shall divide the mainsail leech into approximately equal parts. Headsail battens shall not exceed three in number and two inches in length, and shall divide the headsail leech into approximately equal parts. 11. Headsticks or headboards shall not exceed three-quarters of an inch across the top of the headsails and mainsails. Radio Control Only the rudder, headsail and mainsail sheets may be adjusted by radio control. Concluding Remarks We still want to encourage any existing designs that fit the spirit of the V36 class, such as the school system design of 36-inch LOA or 25-inch LWL (the Seattle Pirate design is an example) and will continue to “grandfather” those designs until the class members determine that they should not. Please look these rules over and send us any comments you have. I intend to use them as the new V36 class rules for the 2007 sailing season, unless I have comments otherwise. Please send comments to me at: asuydam@peoplepc.com or (410) 326-5242 Alan Suydam Vintage Down Under. ell, here we are shipmates. Six years on since our last encounter at the 75th Anniversary of the Marblehead club in Redd’s Pond in 2000. I have written about model sailing in Australia for some years now and my message is still the same as I got from John Snow all those years ago of “think vintage”. Well when I returned to Oz, this was my message too… ‘think vintage’ and I went here and I went there, telling about the new/old Marbleheads, the story I got from Vintage blokes (men) of USA. Well I’ve hung in there, trying this and that to spread the message. ‘Think Vintage’ was the catch cry. At times, I can tell you it was like I was pushing a 4 ton truck up hill. Till I met a friend, who sailed with me bought a rather older type Marblehead; an “oldy but a goody” as the old sailors say. The design we call in Australia, a Maltese Falcon. This was one of the top Marblehead designs about 10 to 15 years ago and they are very quick, without resorting to Carbon anything on them. Of course all the Experts scoffed on this old boat “why did ya’ buy an old boat like that” was the cry? For while it was bought cheap and it was old, it was of sound construction and built originally by the actual designer, so one knew that it was a bargain from the start. Of Course my friend was chuffed (happy) when sometimes his boat got up and won in good company. The ‘Hotshots’ of the club dismissed it as just a coincidence but it A Maltese Falcon Sailing in Sydney Page 5 started slowly to ‘eat’ into the club’s scratch racing results too. For my friend started enjoy his racing. The thing with it all was he was sailing / racing for fun and where winning was a bonus. Some people say this town is the birthplace of independence for Australians. Well in some ways it is also the birthplace for Vintage Marbleheads in Oz as well. Well it all started really from there, I guess. About that time some novices were looking for some information on the web about some early Old Marbleheads called (you got it) Maltese Falcons. Well before we knew it we were into Vintage. These novices are special in themselves for they have talents in other fields and they are prepared to learn and have a go. Down in the “other down under” New Zealand, they are doing great things with old Marbleheads. I recently got a very interesting Email from my correspondent there with a photo of a large group of R/C yachters racing an old 1952 (circa) Dick Priest’s Witchcraft. These boats have the old type keels that lend themselves to be sailed in weeded ponds, like they have in Christchurch in New Zealand on the south Island. While they are sailing them as 10 raters, they are still doing Vintage! Probably we may not be purist as some but doing our thing is better than just thinking about it and wishing it to happen. The theme that we go back to year dot, hasn’t happened yet. Maybe that may never happen? But we have made a lusty start on racing old Marbleheads. Certainly we get boats coming along that are a mismatch of old boats and new bits but the skippers slowly find out that we operate with the FUN aspect to our racing. Each year and this will happen this year when we gather at Ballarat, the historical town in Victoria in the lower state in Australia. We’re meeting at Ballarat in October for our yearly Vintage Marblehead Regatta and how things have changed, I hear the Secretary of the National Australian R/C Yachting Association ‘found’ his old Marblehead the other day and will be joining us at Ballarat, to join the fray’. Down Under Happenings: I’ve just completed a 1952 D.A. Mac Donald ‘China Boy’ Marblehead. I was really happy to see the photo of me on the Marblehead Club web site, after my visit in 2000. (I’m the one on the far right of the picture). If you’re traveling to Australia and are coming to Sydney, come and say G’day at Ancient Mariners, just near the International airport. And as our good mate John Snow says “THINK VINTAGE”. Stephen Crewes. Australia 2006. A group of New Zealand Witchcraft Marbleheads Page 6 ere is possibly the most incredibly detailed and well built operating (RC) model sailing boat you are likely to read about for a long time – the Sea Cloud of Rick Mayes in Queensland, Australia, a model that took him almost eleven long years build, not that he didn’t build a few other boats within that period. Completed in February this year, and then officially launched on the 25th April, the date significant in that the real Sea Cloud was launched in Kiel, 75 years prior to the day. Take a few deep breaths readers, let your eyes run wild over the graceful lines and the utterly amazing detail for a few minutes, Page 7 even t dribble over the pictures, but as admirers you deserve it. The model was made from 6mm ply for the keel and frames, 1.5mm hoop pine ply for planking, the completion of the model an achievement in itself and a 43 year old dream (to model a ship of this style) finally realized for Rick, who went to extreme lengths to include an unbelievably vast amount of detail. Chairs, tables, upper-deck lounge seats all made from Plasticard, lifeboats out of balsa, their covers made from his wife’s stockings, then painted with PVA to hold shape prior to being painted green. On the Lido deck are tables with tablecloths on, and chairs, a bar with cupboards under and behind, and on the forward bulkhead of the aft cabin, a notice board with a photo of the ship and a map of the Agean sea. The wheelhouse is fitted out with wheel and full detail and the model has 98 small working lights. Five winches control all the sails and spars, a standard servo controls the spanker/topsail, two winches control all eleven jibs/staysails, one winch controls the main mizzen mast spars, another the foremast spars. The total length is 7’, the total weight 80 lbs. Four channel radio is used and the model is fitted with a mechanical drop keel with a 6.2 kg lead, and when the keel is lowered it activates the two radars. Some of the incredible detail on Sea Cloud A truly magnificent model, it’s entitled Richard Mayes to receive the Windling World Magazine Model of the Decade Medal. The beauty about `windling’ is that one can create models of almost any boat, with no restrictions as to choice or size or sail area as these are for ‘ windling – the equivalent of `cruising’, and have no fleet compliance requirements. Another friend of the writer, The real Sea Cloud, still sailing today as a cruise ship, was built in 1931 as the Hussar V for Edward Hutton and his heiress wife, Marjorie Merriweather Post, and at that time the vessel was the largest private sailing yacht in the world at 360 feet in length. The Prinz Willem Fred Abbe of Cataumet, MA has produced a beautiful RC model of the gaff-rigged sandbagger Shadow, the original of which was built in 1906. Fred Abbe’s Shadow Fred’s model was built plank on bulkhead using Western red cedar with mahogany trim, a pine backbone and Sitka spruce spars. The dagger board used when sailing is a 6” X 18” peace of stainless steel from an obsolete item of electronic equipment, to which is fitted an 8 lb lead bulb. When not in the water there is a dummy centerboard. The seats and cockpit are removable and the RC servos are not visible but have good access to get at them. Page 8 Modellers of fine operating models abound all over the world and Wim Moonen of the Netherlands is another who spends several years on a project, his latest, the Prins Willem shown here, another good example of the exceptional ship modeling skills of this master model shipwright. Look at the intricate carvings on the stern, those on their own are testimony to ones patience and skill needed to carve them properly. Hope you have enjoyed this little personal delve into the world of the windler, there’s so much more to `show and tell’ believe me but you will have to wait. Happy sailing ! Mark Steele Sea Gull Launched ‘m pleased to report the successful completion of my Sea Gull1 named Short Story. I built it plank on frame generally following the book. “Miserable” is not the modifier I use when refering to the rabbet2. Part of it was my fault in building the backbone out of oak. It may be traditional in big boats but was definitely not the right choice for a mod- “Sittin’ on a dock in the Bay.” Ken Hall and Short Story show windling at its best. 1 A Boucher design whose plans are available from the USVMYG. 2 This is a reference to an article on carving rabbets in our last issues, entitled “Miserable Rabbet.” —Ed. Page 9 el — lots of splintering. I modified the sail plan to evoke the 90 foot America Cup defenders. I used the multiple headsail control suggestions in the newletters for the basic layout. I stacked a double and single cheek block to create triple to keep the sheets from fouling on the access hatch. I originally hoped for a jib topsail but realized it would foul the boom off wind so settled for just a jib and a staysail. I did build a jib topsail for static display. Removing the club topsail serves as a simple reefing technique and results in more of a working boat image. I used the Hitech sail winch for the headsails, a mega sail arm for the main and a rudder servo. I enlarged the rudder; I probably overdid it but have no trouble controlling direction. action works best if the fluid is thin. Ordinary epoxy resin is as thick as honey. This repair utilizes penetrating epoxy, marketed as a dry rot repair. Penetrating epoxy is thinner. It is designed to be readily drawn into the crack, even if it is no more than hairline width. There is no need to gouge out or widen the crack to expose the edges of the plank. As proof of concept, I prepared a small panel of edge-glued 5⁄32″ thick planks. The panel was 6″ x 8″. To simulate a hull, I varnished the “Inside” and painted the “outside”. The finished panel would then be cracked in half, and the two parts reassembled closely but not clamped, so as to create a hairline crack. The epoxy would be applied from the “outside” only. The objectives of the test were: 1. To confirm that the epoxy would reach all the way through the length and depth of the crack, reaching to the inside surface of the planking. I think I ended up a little on the heavy side. Not enough freeboard by my eye and a little down in the bow. I’m planning on taking a core out of the lead keel this winter. 2. To confirm that the panel could be immediately immersed in water; i.e. that all exposed wood was sealed without any subsequent painting or varnishing. Kenneth Hall How to Repair a Split Plank There’s probably nothing a wooden boat modeler dreads more than a split plank on his or her prized classic yacht. Invariably, the damage occurs in a location where there is no possibility of gaining access to the inside. And while the yacht may not sink, its owner experiences a sinking feeling indeed. Well, take heart. Repairing a split plank need not be a difficult or lengthy process. I’ve been giving the subject much study, and I believe I have demonstrated a quick and simple method which will provide a structural integrity equal to the predamaged condition. Furthermore, no tools are required, no access to the interior is needed, and with a little luck there will be no immediate need to repaint the boat. The boat will be fit to sail immediately after the repair. The method I am proposing relies upon capillary suction to draw a special epoxy into the crack. It will draw the epoxy into the furthest reaches of the crack and through to the full thickness of the plank. The epoxy will saturate and seal all exposed wood inside of the crack, and glue the plank edges together with a strength that exceeds that of the wood. Epoxy is also gap-filling, needs no clamping pressure, and needs no surface exposure to “dry” as it is catalytically hardened. Capillary 3. To confirm that the strength of the repair was at least as strong as the wood. 4. To confirm that no additional damage would be done to the painted surface. Indeed, that the surface wouldn’t need to be repainted at all, if so desired. All four objectives were confirmed successfully. After the repair, the test panel was soaked to see if any exposed wood would soak up water (there was none). The panel was rebroken to judge the strength of the joint. It broke not on the glued joint, but at a new location 1⁄8″ away. It was also cut transversely to evaluate how far the epoxy had penetrated away from the crack. It was found, however, that there was negligible epoxy penetration into the sound wood on either side of the crack. The test was performed with the panel horizontal, resting above the tabletop on two small wood strips (which could be a simulation of two ribs, structurally split apart from the planking). In theory, however, capillary action should be strong enough to let the repair be done vertically or even upside down if Page 10 necessary. Capillary action ceases at a free surface, so once the crack is filled, it will stop drawing. Epoxy will not keep flowing and drop into the inside of the hull, unless the crack is so wide that the epoxy will ,,simply run through it by gravity flow. The following are step by step instructions to make the repair. Step 1. Determine the Cause of the Split. All split planks are likely to be caused by either moisture penetration or by direct impact such as a collision with another boat (even if not noticed at the time). The primary evidence is the location: cracks above the water line are likely due to collision; cracks below the waterline are likely due to moisture. Also, moisture penetration will usually cause the paint to lift adjacent to the crack, whereas the paint will remain tight adjacent to an impact crack. Leaving standing water in the boat during storage, or a closed design without hatch ventilation may be the culprit. This repair method will work with either type of crack, but the important point to remember is that with a moisture penetration crack, you will only be treating the symptom, not the cause. Moisture penetration causes cracking because wood swells when it absorbs water and shrinks when it dries out. It will swell and shrink repeatedly with every wetting/drying cycle. The stresses set up by these dimensional changes exceed the strength of any wood and any glue joint. Thus after the crack repair (not before), it will be necessary to ensure that the interior of the boat is sealed. Swirling a quart of varnish around inside the boat (including the underside of the deck), then pouring it out is the traditional cure. Step 2. Let the Boat Dry Out. Before repairing a split plank, the wood must be allowed to dry out long enough to be sure it has dried through the full depth of the planking. For a collision crack detected promptly, this may be 2 or 3 weeks. For a moisture penetration crack, I recommend the boat sit all winter. If you have a moisture penetration crack and a closed, hatchless design, you can never be sure the interior is drying, no matter how long you wait. For this condition, I recommend that you cut in a hatch or remove the deck. Epoxy will harden in contact with water, but moisture in the wood will reduce or eliminate the crack’s ability to generate capillary action, rendering this repair method ineffective. Step 3. Tape the Crack. Carefully apply a strip of masking tape to the paint on both sides of the crack, as close to the crack as possible, and extending about 1″ beyond each end of the crack. For a collision crack with intact paint, you should be able to place the two strips of tape about 1⁄32″ apart or even closer. If it is a moisture penetration crack with flaked or deteriorated paint edging the crack, you may have to place the tape slightly farther apart but not more than 1⁄16″. Don’t remove any flaking paint at this point. To stay within the 1⁄16″ limit, tape directly over bare wood or loose paint if necessary. The object here will be to preserve the paint as much as possible, and promote a clean tear in the epoxy when the tape is removed, as described below. Be sure the tape is pressed down tightly or else the epoxy will creep under the tape. Step 4. Mix up a Batch of Penetrating Epoxy. Do not use regular epoxy. As described earlier, the repair medium must have as low a viscosity as possible to be drawn into the crack. Other types of glue might work with this method. I have chosen penetrating epoxy because it is harmless to paint, hardens slowly enough to permit plenty of time to apply, is gap-filling with no need for clamping pressure, will not in itself cause the wood to swell as it is absorbed, is plenty ,strong for the purpose, and cures at depth catalytically without air exposure. Also, unused epoxy has an almost infinite shelf life. While it’s viscosity is not as low as some other glues, it nevertheless performed well in my test planking. Disadvantages are its expensive price, and potential incompatibility with certain paints. I used West Marine Penetrating Epoxy. A comparable product is Git Rot. You ill need only a tiny amount but may have to mix more as a practical matter just to be able to judge the proportions. Unlike polyester (i.e. fiberglass) resin, where a greater or fewer number of drops of catalyst will influence the working time but not have much effect on the ultimate strength, epoxy’s strength is strongly affected by the proportions of resin to hardener, so measure as carefully as you can. The working time is mostly influenced by temperature not proportions. Read the instructions on the container. Generally speaking, Page 11 mixed epoxy thickens very slowly. It doesn’t “kick-off” suddenly the way polyester resin does. When I conducted my test, it was 74 degrees in my shop and the mix remained thin for about I hour. Mix thoroughly, scraping the sides of the container as well as the stir stick. Step 5. Apply the Epoxy. Now listen up, this is important. DO NOT SIMPLY PAINT ON A SWATH OF EPOXY THE FULL LENGTH OF THE CRACK. For this method to work, capillary action must draw the glue into the crack. If you simply paint on the epoxy with a single stroke, you will trap air inside the crack under the epoxy. Trapped air will prevent capillary suction from developing, and little or no penetration of glue will take place. Sure, you may get lucky, and if the crack extends through to the inside of the hull, the air may escape in that direction. However, we are assuming that the crack is inaccessible from the inside, so you can’t be sure what the inside condition is like. Place a row of single drops of epoxy along the crack about one drop width apart. The epoxy will enter the crack at discrete points and the air in the crack will be free to escape between the drops. If the crack is hairline, it’s volume will be so small that you will not be able to tell that anything is happening, but be assured that within seconds the entire crack will be filled, from one end to the other and to full depth. For a larger crack, you may see little dimples form in the drops. Do not worry that the crack may be “too tight” for the glue to enter. The beauty of capillary action is that the smaller the available space is for the fluid to enter, the stronger the capillary suction becomes. After a couple of minutes, you can apply more epoxy to form a continuous bead of glue. When the epoxy reaches the inside surface of the hull, capillary action will cease. The bead of glue will stop sinking when the wood adjacent to the crack becomes fully saturated. In my test, with a crack 8 inches long, this took less than 5 minutes. No epoxy dripped through onto the table top. However, epoxy was drawn beyond the crack to fill the joint between the back side of the planking and the “ribs” supporting the test piece. Stop for coffee. Check it again in about half an hour. Fill any low spots, if any have appeared. Set it aside. Step 6. Thicken the Glue Line. Wait until the epoxy in the container is about as thick as honey. In my test, this was about 3 to 4 hours. Paint on a thick bead, lapping heavily onto the masking tape. Mound it up about 1/8″ thick. The objective here is to build up a thickness that is several times as thick as the width between the two strips of tape. Stop and wait. Step 7. Allow to Semi-Cure. Epoxy gains strength quite slowly. It will be several days before it is fully cured. At this point, however, we are looking for a scmicured state, where one can still easily dent it with a finger nail. The time will be temperature dependent. In my test, I waited overnight, about 16 hours, which in hindsight, was too long. I could still dent it, but barely. Try about 8 hours. We want the epoxy to be just solid enough to tear as opposed to stretching like taffy, yet still weaker than paint. Step 8. Tear Off the Tape. If you have judged the strength correctly, and gotten your two strips of tape close enough together, you should be able to peel off both strips simultaneously without breaking the 1⁄8″ thick layer of epoxy that joins the two strips. The epoxy between the two strips is only 1⁄32″ wide, so the epoxy should tear right at the paint surface, leaving the crack completely filled and the paint undamaged. In my test, unfortunately, because I had waited too long, the epoxy was strong enough to rip off the paint. All of the paint between the tape strips came off: a line 1⁄32″ wide. The paint under the tape was undamaged. I’m sure that had I removed the tape sooner, the paint would have been undamaged. For a collision type crack repair, if the paint adjacent to the crack is intact, the boat is ready to be used immediately. Aesthetically, the repair is hardly noticeable. From a moisture penetration standpoint, the hull is fully sealed inside and out. From a structural standpoint, the hull is serviceable: even in contact with water, the epoxy will continue to cure until it reaches full strength. Painting is optional, but see the warning below. Page 12 Step 9. Painting. For a moisture penetration type crack repair, tape removal may rip off some loose paint, in which case repainting will be required before the boat can be used. Also, at this point, the inside of the hull should be sealed so the problem doesn’t reoccur. Also, please be aware that some paints will not harden over some epoxies. Try painting over the hardened epoxy left in your mixing container as a test to see if it will dry properly. If it doesn’t, change to a different kind of paint. Alternatively, polyurethane varnish will harden over epoxy and can be used as a barrier layer to keep paint from touching the epoxy. If there is a compatibility problem, even a hairline of epoxy is enough to cause trouble, so be sure to test your paint first: you won’t be able to simply “bridge over” a hairline. Some paints harden just fine over epoxy, but when they’re incompatible, the problem is permanent: it doesn’t matter how long the epoxy has had to cure. In my test, I used West Marine Penetrating Epoxy, and West Marine Brightside Polyurethane paint. I found no incompatibility. Also, please note that epoxy will cure over polyester (fiberglass) resin, but polyester resin will not cure over epoxy. But if you are planning to fiberglass over your entire wooden hull anyway, then the split plank problem will be taken care of at that time and there will be no need to undertake the repair described above. There you have it. In a nutshell: allow to dry, tape carefully, apply epoxy slowly, rip off the tape, go sailing. Mike Stobbe Luthier’s and Instrument Maker’s Planes Tucked amidst their high end planes for furniture making, I spotted an advertisement in the Lee Valley & Veritas Tool catalog (leevalley.com)) for small instrument maker’s planes. These four small planes, with convex soles, ranged from 25mm (1”) to to 47mm (~2”) in size. About to start my plank-onframe 42” Sea Gull, I convinced myself my current 3 5⁄16” palm plane was too big for this project and splurged on the 36mm (~1 3⁄8”) size. Although a bit pricey ($36 and up), I found the quality, fit, and function of this little plane to be outstanding and an excellently sized tool for model making. My “large” plane never saw use. Recently I spotted an ad for what appears to be the same planes in Highland Hardware’s catalog (highlandhardware.com), along with one larger 90mm size and two additional flat sole versions (60mm and 90mm). Page 13 Kenneth Hall Building a Model Yacht Hull Some Notes on Building by the Rib and Plank Method with Photographs of the Model at Different Stages of Construction Editor’s Note ur technical supplement this issue appeared as a series of articles in the magazine Model Ships and Power Boats during the early months of 1953. They describe the state of the British practice of a half century past and provide a useful complement to our Building Planked Models book and the Thomas Darling material we published in our last issue. The author is unknown; the photographs are by F.C. Seignior. We have lightly edited the text. Earl Boebert Building a Model Yacht Hull he first step in building a model yacht is to draw or purchase a design. This should be the work of an expert and experienced designer, as otherwise a lot of valuable time and material may be wasted in producing a model which will not sail as it should. On examining the design the would-be builder, if he is inexperienced, will hardly know how to begin. Usually only the bull lines are shown, and as these are made to the outside of the planking they must be modified before they are transferred to the wood. Further, there is seldom any indication of the constructional features of the boat. These must be decided by the builder himself, and as a beginning he should first make a tracing of the outline of the sheer plan or side elevation. Then he should select the waterline he will use as the top of the keel. This will be the one where the keel begins to widen out into the hull proper. The builder shown in photograph No. 1 has decided on waterline num1 Also spelled “rabbet.” —Ed 2 Also known as “shadows.” —Ed. ber eight, as is shown by the fact that there are eight layers of wood in his fin keel. The inner outline of the stern and stem piece should then be drawn, with a foot or extension for securing them to the keel by means of screws. Allowance must be made where the hull tapers towards the stem so that there is sufficient timber to contain the rebate1 into which the planks will fit. See Fig. 1. Both these features may be seen in the photograph. As the boat will be built upside down on moulds2 fixed to a building board, a datum line parallel with the L.W.L. should be drawn at such a distance above the outline of the boat that it will be about 1⁄2 in. clear of the highest point of the stem. To support the deck there will be an inwale along each side of the hull. If the deck is 1⁄8 in. thick the upper edge of the inwale will lie 1⁄8 in. below the sheer line. This will be drawn on the tracing so that later it can be transferred to the moulds. The body plan or cross section should be considered next. The lines represent the outer surface as already explained, whereas for building we require the out- lines of the moulds on which the boat will be built. As the planking will be, say 1⁄8 in. thick, and the ribs also 1⁄8 in. thick the moulds will be 1⁄4 in. smaller all round the hull lines. A tracing should be made for each mould, and as these are situated at the positions or ” stations ” at which the cross sections on the plans are taken they can be traced direct, but the outline must lie 1⁄4 in. within the outline on the plan. It may mentioned that in the plans the cross -sections are usually drawn full size for the model. For large boats the sheer and waterline plans are sometimes drawn to a smaller scale. The position of the upper surface of the building board, which as already explained is the datum line to which the boat will be built, should be indicated on each of the tracings of the moulds, as also should the position of the upper edge of the inwales. We are now ready to commence building. The building board should be a little longer than the overall length of the hull. For a 10rater or an A-Class boat it should be about two inches thick, and six to eight inches wide; for the smaller boat it can be propor- Page 14 Photo 1: Checking the fit of the keel and rough cut fin on the moulds. tionately smaller. The upper surface should be planed true and smooth, and on it a centre- line should be drawn from end to end and lines at right angles to it at each of the “stations.” The moulds should then be cut out, care being taken to make each one the correct height above the datum line. Notches should be cut out for the keel and the two inwales. The depth of the notches for the keel should be taken from the construction plan, and their widths made to suit the thickness of the stem and stern pieces. The level of the edge of the inwale having been marked on each mould, the slots to receive the inwales can then be cut, the depth and width being made to suit the section of the inwales, Blocks of wood about 1 in. square, and 4 to 6 in. long should be screwed to the base of each of the moulds, by means of which the moulds can be secured to the building-board. Care must be taken to ensure that the centre-line on the mould is correctly lined up with the centre-line of the building board. In positioning the boards, they should be fixed so that the after surface is on the line representing the station for the moulds forward of the midships, and the forward surface of the mould for those aft of amidships. Photograph No. 2 shows the building board with the moulds in position. The keel should be made next. The fin is built up in layers, their shape being taken from the sheer plan on which the half section of the keel is usually drawn on the waterline for the respective sections. Note that each layer must be cut to its wider and longer shape, irrespective of whether the wider surface is the upper or the lower. The thickness of the layers is made equal to the spacing of the waterlines. The uppermost layer (or the lower one with the hull in its building position, upside down) will be wider than the others, and will contain the rebate for the garboard strake, this being the lowest plank on each side. The lead keel should be ignored at this stage and the keel made completely in wood. When the hull is finished, the portion representing the lead can be cut off and used as a pattern for the lead casting. The stem piece and stern piece should now be cut to the outline on the tracing of the construction plan. If the position of the different ” stations ” is marked on Page 15 the side, they can normal transom it be inserted in the should be fitted into a slots in the moulds block of wood out of which will give an which the transom is indication of the formed. See Fig. 2. The amount and angle level of the top of the of the bevel restern is lower than that quired. It must be of the stem, so after alremembered that lowing an extra 1⁄2 in. or the bevelled surthereabouts on the face should be 1⁄8 transom block for in. proud of the screwing down, the curved surface of remainder should be the moulds, to almade up by a block of low for the thickwood of the correct ness of the ribs. Slots thickness. This can be Fig. 1: The keel at the stem. should be cut at each screwed to the transom mould to accommodate and then screwed down the ends of the ribs, which are 1⁄8 in. thick and to the building board as shown in Fig. 2. With 5⁄16 in. to 3⁄8 in. wide. There will be no rebate the stem and stern piece in position on the on the stem and stern pieces where the hull is mould and secured at the ends, the inner of a flat “V” section, but at the curve of the ends should be trued up and made parallel stem where the angle becomes acute, a rebate with the datum line. The keel can then be laid should be cut so that solid wood is left at the in position, and the position of the holes for prow. Elsewhere along the centre of the boat the screws marked through from those althe planks simply meet, their ends being ready drilled in the stem and stern pieces. bevelled to suit. The stem piece should have These pieces should then be removed from an extra piece- allowed at the forward end as the moulds and glued and screwed to the shown in Fig. 1 so that it may be screwed keel, making sure that all three sections are in down to the building board during construcline. The assembly can then be replaced in tion. The after end of the stern piece is fitted position on the moulds and the ends screwed into a block which forms the transom. Where down again. the transom is extremely narrow, or is non- Photo 2: The moulds on the strongback existent, in which case the boat would be a double ender, the stern may be in one piece, as is the case with the stem. But with the The inwales should be fitted at this stage. They should be 1⁄4 in. thick, and 1⁄2 in. or 5⁄8 in. wide for a 10-rater and even larger for an A- Page 16 Class; we must have something substantial to which we can secure the deck. Slots to receive the ends should be cut at the stem and in the transom, their positions being 1⁄8 in. below the sheer line as shown in the construction plan. These, in conjunction with the slots already cut in the moulds should receive the inwales, holding them in an easy curve from stem to stern. The surface of the inwales should lie flush with the surface of the moulds and the slots in the keel assembly should be trued with the moulds so that their depth brings the inwales flush. Finishing The Framework In order to be able to remove the building board after the hull is planked, the screws which secure the blocks on the moulds to the building board should, after the moulds are all in position, be replaced by screws from the underside of the building board. The original screws are shown in Figs. 1 and 2, and these must be removed before planking. The screws shown holding down the stem and the packing under the transom piece may remain, as they are accessible after the planking is completed. The transom piece is held down to the packing by screws from underneath which can be removed after the building board has been taken away. As already explained, the moulds are 1⁄4 in. less all round than the section Shown on the body plan but the transom piece should be only 1⁄8 in. smaller, as in this case, only the planking has to be allowed for. The removal of the moulds after planking is sometimes quite a problem, especially if the pins securing the planks to the ribs are allowed to project even ever so slightly into the moulds. The moulds can be removed from inside the ribs by tapping thqm gently toward amidships, after which they can be turned slightly fore and aft so as to clear the inwales. The moulds in the centre between the stem and stern pieces can be turned easily, as they are not notched to fit the stem but the other will need sloping until the notch is clear of the backbone of the hull before they can be turned. Another method is to make each mould in two halves, dividing them along the centre line. The two halves are held together by the block which secures them to the building board. Nearer the keel a thin piece of wood, about 1 in. wide by 3 in. long can be nailed on as additional security. These pieces can be prised off after the planking is finished, and the screws securing the moulds Fig. 2. Transom Piece with Keel and Inwales to the blocks are near enough the edge to be removed without difficulty. The two halves can then be pushed to clear one another, after which they can be taken out quite easily. It is important to prevent the glue used in planking from adhering to the moulds. To do this it is advisable to give the moulds a coating of one of the non-adhesive varnishes made for use with modern resinous glues, working it around the edges and in the notches for the inwales and the keel. Another scheme is to lay a sheet of thin paper or cellophane between the mould and the ribs. In speaking of the slots for the inwales in the transom and stem, we said that they should be such that the inwales would be flush. Some builders, however, make the slots deeper to the extent of the thickness of the ribs, so that the inwales are parallel to the planks throughout. This is, of course, correct boat building practice, and looks better, but there is no disadvantage in having the inwales closing up from the first and last moulds to touch the planks at the ends of the hull, and the flush inwale makes a better foundation on which to secure the planks. Before fitting the ribs, the builder should obtain a batten about the length of the hull–one of the strips for planking will do-and test the moulds for fairness. In any fore and aft position the batten should touch each mould without strain. If some moulds are below the batten the high spots on the adjacent moulds should be rubbed down with a rasp until all the lines are fair. For the best results the moulds should be bevelled so that the batten is in contact with the mould throughout its width. This rather increases the difficulty of getting the rib to lie nicely along its surface, Page 17 but is worth while as otherwise the rib itself must be bevelled and in some cases this reduces the thickness of the rib on one edge until it may be too thin for its job. The ribs should be made of ash or elm or some similar wood which is reasonably tough, and which can be steamed or bent. They should be cut to length, each pair being long enough to project about 1 in. below the inwale at their respective moulds. Steam or boil the strips until they are quite pliable, then fit them one by one into the notches in the keel or backbone of the hull, securing each one with glue and a screw. As they are fitted they should be pinned to lie closely to the moulds, leaving the pins or brads projecting so that later they can be withdrawn. The lower ends can be tied across the mould with cord so that they are in close contact with the inwales. This will be seen on Photograph No. 3. Before the cords are drawn tight, the ribs should be glued to the inwales, and after the cord is in position a small screw can be inserted to make doubly sure, care being taken that the point of- the screw does not project through the inwale and into the mould. The 1 assembly should now be put away for a few days, until the glue is quite hard and everything is set. On resuming work, the ribs should be finally faired with a batten as already described for the moulds. The rebate in the wide layer of the keel where it joins the hull (see Fig. 3), should be trued up at this stage. It should come to a point at each end of this layer as will be seen in Photograph No. 1. The ends of the ribs should now be cut off level With the edge of the inwales. Preparing to Plank Various woods have been recommended as material for planking. Cedar or Parana pine1 are suitable if the hull is to be painted, but if it is left in its natural colour and varnished, the best material is undoubtedly mahogany. In this case the keel, the backbone and the transom should also be made of mahogany, although the transom piece may be of pine or similar wood, so long as it is covered with mahogany on its after surface. In preparation for planking, the width of the planks should be marked on the rib at the midship section. Photograph No. 3. Early stages in the planking. A species of pine from Brazil. –Ed. Page 18 For a 10-rater or an A-class hull the planks should be about 3⁄4 in. width amidships. If they are made wider they do not sit nicely on the ribs and the outside surface is inclined to be ridgy. The planks should taper gradually toward each end, but nowhere should they be less than say 3⁄8 in. in width. Even then very few of them will reach to the ends of the hull, the others meeting on the backbone, the joint being on the centre line. The run of the planks up to these joints should be symmetrical in appearance, as this is one of the features of a well-built hull. The sheer strake which is the uppermost one at deck level, may be slightly wider and not quite so tapered as the others. Most builders commence with the garboard strake, which is the one nearest the keel, and while some carry on and finish with the sheer strake, others fit the sheer strake next after the garboard strake and work both ways, finally meeting about half way, at the turn of the bilge. The object of this is to be able to see the run of the planks more clearly, and to enable them to get the taper of the planks spread evenly throughout. It is the easiest thing in the world to start planking, and to find by the time the sheer strake is reached that the last planks are too tapered or too parallel. In either case it spoils the look of the job. A hull built with the planks nicely tapered throughout is one of the most beautiful examples of woodwork to be seen. This even taper can be worked out on the body plan before the planks are cut. Fig. 4 will make this clear. A tracing should be made from the full sized body plan, this time making the outlines 1⁄8 in. inside the actual lines on the plan, as this represents the surface of the ribs and the inner surface of the planking. The lines A and B represent the upper and lower surfaces of the uppermost layer of the fin keel, and CC the extent of the rabbet for the garboard strake. Lines from CC to the upper surface A represent the rabbet in the keel running from C amidships to each end of the layer. If the width of the planks on the midship section is then marked in, lines can be drawn from each point to the centre line, making them flow symmetrically as indicated in Fig. 4. These lines represent the joints between the planks, and the points for each section should be transferred to the appropriate rib. If the planks are fitted to these points as the work proceeds, they will be found to be gradually tapering from amidships towards each end and the finished hull will have the desired symmetrical appearance. Planking We are now ready to begin the actual planking of the hull. Each builder has his own particular method or order of procedure, but the one described is based on the writer’s own experience, and has been found to produce satisfactory results. Commence with the garboard strake. To get the correct shape for this’ take a piece of fairly stiff brown paper a few inches larger than the plank and about 3 in. wide and lay it along the side of the fin approximately in the position where the plank will lie. Then rub it with the hand and fingers so that the edge of the rebate is indicated by a depression in the paper. With somewhat grubby fingers on a light coloured piece of paper, the edge of the depression will be quite obvious. The vee along the top of the stem and stern pieces can be indicated in a similar manner. Care must be taken that the paper lies easily along the hull and is not creased or forced out of position. The paper should then be cut along the rubbed depres- Fig. 3. Notch for ribs and rebate for garboard strake. sion, after which one edge of the planks can be shaped to its outline. On offering this up to the boat it will be found to fit the rebate fairly closely. Any slight discrepancy can be removed by means of a fine rasp or file until the fit is perfect. When the plank is correctly fitted along one side its width must be con- Page 19 sidered. Mark off along its length the position of each rib, numbering them as you go, and then with a pair of dividers scribe, at each point, the width of the plank at its particular station. These widths are taken from the markings on the ribs, which were explained in our last issue. It will be found that the length of the plank is much greater than the length of the rebate owing to the amount required for the bevel at each end where it meets the plank on the other side. See Fig- 5. The plank should now be planed to the correct width, care being taken to maintain a smooth run throughout. I use a plane with a blade about 1 in. wide. It will usually be found that the garboard strake is wider at each end than amidships. A second plank should now be made, using the first as a template. On offering this up to the other side of the hull, it should be found to be a good fit. Any slight discrepancy there may be can be put right by a touch from the plane. The long pointed ends of the garboard strakes, and in fact of all the strakes, which meet one another on the underside of the stem and stern pieces can be planed with a slight bevel so that the next strake above it (when the boat is in its normal position) overlaps it slightly. This will help to protect the pointed ends of the planks, especially when sailing if the overhangs of the boat run up on to the bank at the edge of the sailing water. This entails a little extra care in fitting the plank to the one preceding it, especially towards the ends, but is well worth the trouble. Another scheme is to continue the rebate from the stem right along the stem piece and into the fin. The tapered ends of the planks would then be fitted into this rebate, forming a flush surface. The stern piece would be treated similarly, and a projection corresponding to the raised centre piece should be left on the transom piece. An alternative method for getting the shape of the edge of the plank is to use what is known as a “spiling plank.” This is a piece of wood about 1⁄8 in. thick by 3 in. wide. It is bent over the ribs with one edge touching the rebate at a, see Fig. 6, and equidistant from the ends of the rebate as shown by b, c. Having this distance in the dividers, points c are scribed on the plank from the rebate. as shown in the drawing. These points are continued at each end from the centre line of the stem and stern pieces to give the bevel which will make the joint with the plank from the Fig. 4. Diagram showing run of planking opposite side. A line drawn through the points c, c, c, indicates the shape of the edge of the plank which fits into the rebate. The other edge giving the width of the plank can be obtained as already explained. It will be observed that the plank has a definite curve. The object of going to the trouble of finding this curve instead of forcing a straight plank to follow the curves of the hull, is to ensure that the planks will lie on the ribs in their proper places without any strain. If the planks are strained into position the hull will be full of internal stresses, and sooner or later, under varying atmospheric conditions, it will be twisted and pulled out of shape, thus rendering it useless for accurate sailing. Another point to be noticed is that whereas the curve of the garboard and its adjacent strakes is in one direction, wrapping themselves around the fin, so to speak, the curve of the sheer strakes is in the opposite direction. This explains why the lower strakes are wider at the ends than in the centre. As we approach the sheer strakes, the fact of the perimeter at the stem and stern being less than that at the midship section causes the opposite effect, viz., that the planks are wider amidships than at the ends. The transition takes place somewhat below the bilges, at which point the plank is more or less parallel throughout its length. Having satisfied ourselves that the garboard strakes are a perfect fit, they should be fixed in position by means of small brass screws, size 0 x 1⁄4 in. or 3⁄8 in., two at each end. Where Page 20 Photograph No. 4. Fitting planks at the bilge. they cross the ribs the strakes should be pinned by means of 1⁄4 in. panel pins.1 The next pair of planks should be fitted in a similar manner, the paper strip or spiling planks being used to get the shape of the edge next to the garboard strakes. The planks must be fitted in pairs as the work proceeds so that any strain that may be set up by bending the planks over the ribs is equalised on each side of the hull. The second and subsequent pairs of planks should be glued, at each end, at each rib, and along the edge joining the preceding planks, before screwing and pinning in position. The last few pairs of planks will fit into the rebate at the stem, and on the transom piece at the stern. Where the width of the plank warrants it, two pins should be -driven in at each rib, one being forward and one aft of the centre line, so that there is no possibility of splitting the rib. The widths of the last pair of strakes before the sheer strakes are a little wider, and more parallel than the lower strakes. If the ribs have 1 been marked as recommended, and the marks strictly followed as the work progressed, there should be no difficulty in this. The sheer strakes should be 1/8 in. above the inwales, and the ends of the ribs, from end to end. Finishing the Planking The individual planks, being flat when fitted, present a surface which is a series of flats stretching from end to end of the hull. In rubbing down, the action at first should be across the grain, using a diagonal or circular motion, in order to get an easy curve throughout the entire surface. Towards the finish the action should be in a fore-and-aft direction, and the finest grade glasspaper must be used. Only sufficient rubbing down to take out any flats, and to produce a smooth surface, should be used, as any excess will tend to produce ridges at the ribs where the heads of the pins form a surface somewhat harder than the remainder of the wood. I have seen planked hulls where split As will be described later, toothpicks are preferred for this task.–Ed. Page 21 Fig. 5. Fitting the garboard strake. bamboo pegs or tiny hardwood dowels have been used instead of brass pins, but this is more suitable for models of old time ships, where the dowels represent the treenails or “trennels,” which were used in the prototypes. This method certainly simplifies the rubbing down process1. We are now ready to take the hull off the building board. To do this the screws securing the mould blocks from underneath must first be removed, and then the screws holding the packing piece at the transom block and the extension to the stem. The hull can then be removed from the building board. Next the blocks must be removed from the moulds. This is quite easy as the screws securing them are accessible. If the moulds have been made in two halves the strips nailed on to hold them together near the keel can be prised off with a screw-driver, when the moulds can be pulled out of the hull without difficulty. If the moulds are in one piece the centre ones, which are not slotted for the keel can be twisted round to clear the inwales and then removed. Those which have slots for the stem and stern pieces, must be moved over towards the midship section, until the slot clears the stem or stern piece, as the case may be, after which, they can be rotated to clear the inwales and then withdrawn. A careful check should now be made to see that the beam of the boat agrees with the design. If the hull has sprung, it should be pressed back gently to the correct beam, and temporary ties screwed to the inwales to keep it the correct beam until the deck beams are fitted. These temporary ties should be fitted in any case, as the hull will be subjected to a considerable amount of handling before the deck is put on. If the ribs have been spaced anything less than 4 in. apart, it will not be necessary to fit additional ribs between them. These additional ribs are usually fitted on skiffs and similar light open boats, but their purpose is as much to protect the planks from wear and tear from the users of the boat, as to impart additional strength. 1 This is the method preferred U.S. builders. A 1/16 can be ground Fig. 6. by Diagram showing use in. of drill the spiling plank.to match the taper of toothpicks, which are used as “trennels” or (as it is sometimes spelled) “trunnels.”—Ed. 1 Page 22 The gaps between the inwales and the sheer strake between each rib should now be filled in. Slips of the material from which the ribs were made could be used as they are of the correct thickness, and will require a minimum of fitting. They should be glued in position and pinned through from the the inwales, to avoid having pins showing on the outside. The inside of the hull should now be varnished. The first coat should be thinned down with turpentine so that it penetrates well into the pores of the wood. At least two more coats should be applied, and only the best boat varnish should be used. Fin, Skeg, and Ballast The fin should be made at this stage, if it has not been made already. It is built up in breadand-butter fashion, the thickness being exactly that of the space between the waterlines on the plan. This is important, as otherwise the outline will be deeper or shallower than the correct one. The lead line may be ignored at this stage, and the fin built up as though it were made entirely of wood. The shape of the layers must be taken from the waterlines on the plan ; it is, of course, necessary to cut to the larger outline, irrespective of whether this is on the upper or the lower surface of the layer, see Fig. 7. The centre-line of the hull must be marked on all four surfaces of each layer, and the positions of the sections or ribs should be drawn across and down each side of each layer. Positions should be indicated for the bolts securing the lead, and holes for them drilled through each layer, care being taken to position them accurately. Suitable positions for the bolts may be selected from a consideration of the lead line which will be shown on the plans. As these bolts will be used later to take the handle for carrying the boat this should also be taken into consideration when deciding their position, especially in the case of a large model, where the position of the handle in relation to the centre of gravity of the boat will make a great difference to the ease and comfort of carrying it. The layers should now be glued and bolted together. If the bolt holes have been posi- tioned accurately the layers will be in the correct relation to each other, and with centre lines and station lines all matching perfectly. In bolting together the layers of the fin after gluing, packing pieces should be used under the nuts and under the bolt heads, to avoid making depressions in the wood. The bolts will provide sufficient pressure for holding the layers until the glue is set. The fin should then be carved approximately to shape, leaving the final shaping to be done when it is in position on the hull. Holes for the bolts should now be drilled in the lowest layer of the hull, and, if they extend to this position, through the feet of the stem and stern pieces where they are secured to it. It is important to position these holes accurately. To finish the fin, bolt it firmly in its position on the hull and shape it accurately, using templates to match it at each station with the corresponding position on the hull. It should then be detached and the lead-line marked on. The portion representing the lead can then be cut off, and should be used as a pattern from which to make the lead casting. Unless the builder is anxious to make his own casting, and has some experience in the art, he would be well advised to take his pattern to a small foundry and get them to make it. 1 Suitable bolts of the correct length should be installed in the lead, the heads being embedded in it, and the screwed ends projecting. The fin, with the lead in position, should now be glued and bolted to the hull, great care being taken to see that it is truly vertical to the L.W.L. or the deck line. When set the lead should be filed and scraped to its correct form, as shown by the templates already used in shaping the fin. The skeg must be made next. Some builders prefer to form this in one piece with the stern piece, but as it is quite thin in section, as compared with the stern piece, it is better to make it separate. Of recent years many modifications have taken place with regard to the shape of the skeg. Instead of the wide, shallow rudder, usually used with the Braine steering gear, the vane seems to call for a nar- There are, of course, few if any of these left. There are two viable options for ballast. One is to laminate the shape from sheet lead flashing, available from roofing suppliers, epoxied together and then shaped with a wood plane copiously lubricated with mineral spirits. The other alternative is to build the ballast up from copper or brass. This requires linear dimensions to be expanded by 5%. 1 Page 23 row deep rudder, especially when the rudder is placed well aft. Naturally, this has affected the shape of the skeg and the present-day tendency is to make this quite short in fore and aft direction. However, the designer to whose drawing you are working will have his ideas on this point, and unless the builder has had a wide experience in designing and sailing model yachts, he will be well advised to stick to the shape shown in the drawing. The fore and aft position of the skeg should be marked out on the outside of the planking, and a series of holes of a diameter about 1⁄16 in. less than the thickness of the skeg should be drilled through the planking and through the stern piece. The holes should be vertical, or in other words at right angles to the L.W.L., and not at right angles to the shape of the profile at this point. In this way it is easier to ensure the correct location of both the skeg and the rudder stock. The wood between the holes should be split away and the slot opened out with chisel and a fine rasp until it is a tight fit for the skeg. It is advisable to include the hole for the rudder tube in the slot for the skeg. This means that the slot will be squared at its forward end, but rounded at its after end. See plan in Fig. 8. This obviates an awkward drilling operation, and ensures that the rudder tube fits snugly against the after side of the skeg, which should be hollowed to fit it. The skeg should now be glued into position, taking care that it is pushed well forward in the slot to allow space for the rudder tube. The ends of the planks, which were cut away when making the slot, should fit snugly along each side of the projecting skeg. If the model is to be painted, a fillet of plastic wood along each side of the skeg would be an advantage. In a varnished hull this would look rather unsightly. The rudder tube should now be fitted. This is made from a light brass tube of from 1⁄4 in. to 5⁄16 in. diameter, according to the size of the boat. It should be cut off to such a length that when flush with the bottom of the skeg, the upper end will project about 1⁄4 in. above the level of the deck. The lower portion outside the hull should be filed away to rather less than half its diameter. A brass plate of i in, or more in diameter should then be drilled to fit closely on the outside of the tube. It must be eased slightly fore and aft, and then pressed down on the tube at such an angle that it lies snugly on the inner side of the stern piece. It should then be soldered to the tube, which Fig. 7. Construction of fin and lead keel may be done in position, or, if preferred, the tube could be withdrawn from the boat, taking care not to disturb the position of the collar in so doing. When the collar is soldered in its correct position, the tube should be reinserted in the boat and secured to the after side of the skeg by means of small brass screws. The heads of these should be countersunk and finally filed flush, so that they are well clear of the rudder stock which fits inside the tube. Four holes for small screws should then be drilled through the collar and into the stern piece. The screws may have round heads. The rudder tube and its collar should be well coated with adhesive before being fixed. The plate on the bottom of the skeg is of brass, and after fitting, the corners should be rounded off smooth and flush with the wood. At its after end a brass pin is riveted in. The larger diameter of this pin is made an easy fit for the hole in the base of the rudder stock. The upper end is pointed and forms a pivot on which the rudder is supported. The lower end is reduced in diameter to form a shoulder against which it can be riveted into the strip. Preparing the Deck We are now ready to consider the deck. First, deck beams must be made and fitted in position. These may be made from any reasonably tough hard wood, or even a good quality pine would be suitable. If the deck is to be made from 1⁄8 in. thick wood, the beams in an “M” class or larger boat could be spaced from 4 in. to 6 in. apart, but if thinner wood is used, or thin three-ply, the beams must be somewhat closer together. They should be positioned so that one is near the mast position and another is near the rudder post so as to give, the necessary additional support at these places. Over the carrying handle the Page 24 deck beams should be sufficiently far apart to enable the width of the hand to pass between them, say 5 in. minimum. Two carlins or beams running fore and aft should be fitted between these beams to form the hatchway. The upper surface of the beams should be curved to suit the camber of the deck, while the lower edge should be straight to give added strength. Incidentally it has been pointed out that, although a camber on the deck gives a boat a more “shippy” appearance, it is not really necessary in a model yacht, as she never sails upright when taking water on the deck. The only purpose of the camber in a full sized ship or yacht is to allow water to run off freely. The only time water lies on a deck is when the vessel is moored and it is raining, and these conditions do not apply to model yachts. However, a camber on the deck beams above or below would strengthen them where they most need it. Recesses should be cut in the inwales to receive the deck beams. These should be a close fit for the ends of the beams, but need not be for- the full depth, as otherwise the inwales might be seriously weakened. The Deck The deck should be made from a sheet of good quality sycamore or similar close grained wood, and if possible it is better to make it in one piece. Some builders prefer to use resin-bonded three-ply 1⁄16 in. or 1 mm. thick. This is light, strong and waterproof and will not split and, provided it is sufficiently well supported by deck beams, it makes a very satisfactory deck. For shaping it should be laid on the hull and the outline marked on it all around. A second line can then be drawn 1⁄8 in. inside this, after which the deck can be cut out until the inner of the two lines is just showing. It should then be fitted carefully to the hull as, although the joint is covered later, a good fit here helps to ensure a watertight hull. It will be remembered that the sheer strakes were left 1⁄8 in. above the inwales, and the upper ends of the ribs, and it is assumed that the top of the stem piece from the ends of the planks forward was cut off flush with the sheer strakes and the remainder flush with the inwales. The top of the transom piece will be 1⁄8 in. below the sheer strakes. It is a nice refinement to cover the end grain of the transom piece and of the planks with a 1⁄8 in. layer of mahogany and this could project 1⁄8 in. above the transom piece to be flush with the planking. Fig. 8. Section and plan of the skeg and rudder Thus the deck will be completely surrounded, and nowhere will the end grain appear, or if three-ply is used, the edges will be completely enclosed. Holes for the hatch, the mast and the rudder tube, should now be cut. The hatchway should be left small for finishing later. It will be found more convenient to do the lining of the deck at this stage, rather than later, when it is in position. It is easier to make the lines straight, running parallel with the centre line of the hull, but a really smart yacht invariably has its deck planking running parallel with the bulwarks, the ends being fitted into the ” king ” plank, which runs down the centre line. Figure 10B. shows the first scheme and Fig. 10A the second. In either scheme a space between the covering board-shown black in the drawings-and the planking is left plain to represent the waterways of an actual ship. A king plank about 3⁄4 in. to 1 in. in width is shown down the centre line. In a ” laid ” deck this would be a piece of dark wood, but in our model it can be represented by staining the wood. Similar planking, mitred at the corners, should be shown around the hatchway. The remainder of the Page 25 deck should now be filled in with lines to represent the planking, making the lines 1⁄4 in. or so apart. Before drawing the lines the deck should receive one or two coats of clear size to prevent the ink running when doing the lines. Waterproof indian ink should be used for the lines and they should be drawn with a draughtsman’s ruling pen. For curved planking, as in Fig. 10A, the pen should be fixed into a marking gauge and the edge of the deck used for guiding the pen. As a refinement the ends of the planks cculd be shown joggled as in Fig. 11A or B. Fig. 11A shows the planks joggled into the king plank for curved planking and Fig. I 4B shows them joggled into the waterways for straight planking. The rules for joggling deck planking are as follows: (1) A plank must be joggled if the “snipe” or bevel is longer than twice the width of the plank, and (2) the squared end must be half the width of the plank. Rule 1 is important, and limits the number of planks to be joggled. Attention to both these rules would prevent the absurdity sometimes seen. where, with curved planks, the king plank is cut away to such an extent, that it would be useless for its purpose, which is to strengthen the deck in a fore and aft direction. The various fittings to be fixed to the deck should next be considered, and at every point reinforcing pieces must be glued to the underside to take the screws which hold down the fittings. The underside of the deck and the interior of the hull should now be varnished with two or three good coats. When all is dry the deck should be put in its place with a good layer of white lead1 on the joint. It must be pinned or screwed to the inwale, screws being preferable in case it should have to be removed later. When the deck is screwed down the heads of the screws, if projecting, should be filed flush. It is assumed that countersunk screws have been used. The covering board (see Fig. 12) should now be fitted. It should be made of mahogany or any similar dark wood, and is in three pieces, two along the sides, these being about 1⁄8 in. thick and 3⁄8 in. or 1⁄2 in. wide, and one at the stern, this being shaped to fit the transom and carried forward to butt on the end of the side pieces. This will be seen in Fig. 10. The covering board must not 1 overlap the waterways, and should be secured with light pins or fine countersunk screws. The hatchway should be tackled next. The edges of the deck at the opening must be cut and filed flush with the deck beams and the carlins, and a strip of mahogany 1⁄8 in. thick fitted and pinned in position. This should project about 1⁄4 in. above the deck to form the hatch coaming (see Fig. 13). The corners will, of course, be mitred. At this stage the deck should be varnished to seal all joints in the woodwork. The hatch cover should be of white wood, and may project very slightly beyond the coaming. A piece of cork which has been made a tight fit for the hatch should be glued to the underside of the hatch cover so that when the cover is in position it is held securely, and is watertight. The hull is now finished except for the painting. Our object in this series has been to help and encourage those who wish to build a planked hull, and who may have difficulty in translating the lines as shown in the design into the hull of the actual yacht. We have not dealt with the making of the spars, sails, steering gear and other special fittings, as these, depend on the builder’s choice of design, on the size of the yacht, and on the particular type of steering gear to be used. Anonymous (1953) The Model Yacht is published three times a year by the U.S. Vintage Model Yacht Group. Copyright 1998 to 2006 U.S.V.M.Y.G. Reproduction for noncommercial purposes permitted; all other rights reserved. Other copyrights are maintained by the original holders and such material is used here under the fair use provisions of the relevant copyright acts for nonprofit research and educational purposes. Editorial Address: 9219 Flushing Meadows NE Albuquerque NM 87111 This material is deservedly extinct. Silicone seal or other waterproof caulk should be used. Page 26 A B Fig. 10. Alternative methods for lining the deck. Email: boebert@swcp.com Phone: 505 823 1046 Officers of the U.S. Vintage Model Yacht Group: President: John Snow Eastern Vice-President: Ben Martin Western Vice-President: Dominic Meo, III Midwest Vice-President: Tom Pratt Southeastern Vice-President: Thom Mclaughlin Vintage M Class Coordinator: John Henson Vintage 36 Inch Coordinator: Al Suydam A Class Coordinator: Rod Carr U.K. Coordinator: Graham Reeves Canadian Representative: Doug McMain Historian: Earl Boebert Archivist: Jim Dolan A B Fig. 11. Joggling of planks in king plank and covering board Fig. 12. Section showing details of deck and covering board Page 27