The Model Yacht: Volume 8, Number 3 – Winter 2004-2005

LINCOLN MEMORIAL POOL, WASHINGTON, D.C. NEWSLETTER OF THE U.S. VINTAGE MODEL YACHT GROUP VOLUME EIGHT, NUMBER THREE Winter 2004 – 2005 NEWSLETTER OF THE U.S. VINTAGE MODEL YACHT GROUP VOLUME EIGHT, NUMBER THREE Winter 2004-2005 Editor’s Welcome All I can say is we’re getting less late each issue, and hope to be back on schedule by the next issue. Even so, it is with a certain amount of pride that we close out our eighth year of publication, a mark that, of course, we could not have attained without the steady support of our readers, for which we are deeply grateful. In this issue we include as wide a range of subjects as we ever have, from a simple “grandparent’s boat” to a glass-over-balsa version of the J boat Whirlwind to sail alongside Yankee III. For the scale model enthusiasts we offer an essay on sail nomenclature and plans for a great little cruising yacht. 2005 is going to a heavy travel year for us, and we hope to see many of you at Woods Hole, Clayton, New York, or Spring Lake. And of course in June we’ll be free sailing in the United Kingdom at the historic venue of Gosport and Bourneville. A full report will appear in our next issue. We do ask that you take a moment to check the number that follows your name. This is the volume and number of the last issue we think your subscription runs to. This is Volume 8, Number 3, so if the number is “83” it’s time to renew and there should be a note to that effect and a self-addressed envelope. As always, if you think we have it wrong, let us know and we’ll fix it right up. Earl Boebert Ebbs and Flows The President’s Message Vintage Membership VMYG annual membership remains at $20 for three issues of our newsletter – “The Model Yacht”. It is $25 for members outside of USA to cover mailing costs. 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 at 781-6314203 or visit VMYG Web Page at: www.swcp.com/usvmyg 2005 VMYG Activities April 16 & 17 Biennial Woods Hole Model Boat Show, Cape Cod, MA. Overall coordinator is John Snow, VMYG President at 781-631-4203 and: jsnow@drc.com for inside Vintage and AMYA model exhibits. Show’s AMYA invitational regatta is April 16th at Eel Pond; contact Jim Linville for regatta details and entries at 781-925-0045 and: jimisu@comcast.net June 3&4 Family Day, Antique Boat Museum, Clayton.NY. Coordinator is Pete Maxson, AMYA Region 1 Director at 585-637-3603 and: pmaxson@rochester.rr.com Page 1 Over and under 40 inch R/C model sailing demos are planned plus possible model displays inside Museum. September 9-11 VMYG 11th VM National Regatta, Spring Lake, NJ. Coordinator is John Henson, VMYG VM Coordinator and Spring Lake MYC Commodore at 732-458-1370 and: senlivjh@aol.com R/C VM racing and display, with possible V36 model sailing as well. Traditional Watercraft Regatta, Calvert Maritime Museum, Solomons, MD. Coordinator is Parker McClellan, Solomons Island Model Boat Club Commodore: February 2005 issue of Sail magazine will have six-page story on sport of R/C model yachting. It will include sidebar on launching of Bill Bithell’s new Ranger III R/C A Class model at Redd’s Pond, Marblehead in November 2004. This model is based on original 1947 Ranger design, which won 1949 World Championship as free-sail vane boat with Bill as its skipper and builder. Note Bill is now 94 years young, with Ranger III being co-launched by Bill and his son Larry. VMYG Material September 23-25 VMYG Annual shadow1954@earthlink.net R/C schooner and skipjack-type traditional models regatta and displays, with additional racing for VM and V36 models. VMYG “how to” book and video package on plank-on-frame construction, plus new “how to” Yankee III J Boat model building book are available via VMYG Web site. Also, copies of 2004 The World of Model Yachts exhibit catalog are still available. John Snow New Mid-West Representative VMYG has new Mid-West representative, Tom Pratt, who scratch-builds traditional sailing craft models. He currently has two R/ C models of Bluenose fishing schooner. Feel free to contact Tom on VMYG activities in his area, about hosting vintage event and VMYG support for it, and traditional schooner-type models. Tom’s contact info: Tom Pratt, 6517 Morrow-Rossburg Road, Morrow, OH 45152; 513-899-4748 tomsbarn@go-concept.com Vintage Etcetera Vintage 36-Inch (V36) Models VMYG continues to monitor interest in V36 designs. Earl Boebert and John Snow plan to attend third biennial International Challenge Cup Regatta in UK from June 18-26. Racing involves two free-sail regattas with Vintage 36 Restricted Class design models and competing US and UK skippers. Historic UK model yachting venues will host these V36 races at Gosport, June 18 & 19, and Bourneville, June 25 & 26. Graham Reeves, US VMYG representative in UK, is overall coordinator of these events and can be contacted at: ga.reeves@virgin.net Publicity Porty It doesn’t get much simpler than this. A single block of wood for a hull, another for a fin, some ballast and rig material and you’re in business. The design was used by the Industrial Arts Department of the Portland, Oregon school system, probably for 9th grade or so. Based on the appearance of the original plans and some pencilled notes on the back of a different set acquired at the same time, I estimate the design dates from the 1945-1950 time frame. Perhaps the sight of these plans will jog the memory of one of our members. The missing stern dimension on the plan, which was pencilled in on the original, is “1/ 2 Beam.” Despite its simplicity, Porty is a handsome little boat and would make a great project for a grandparent or a workshop class. If you’re nervous about casting lead ballast, the shape is simple enough to be sawed out of a slug of copper or brass and filed to shape. Polish that up nicely, match to a nice paint job and bingo! Instant heirloom. VMYG will again be featured in AMYA’s Model Yachting magazine in 2005 Spring issue. We have 20 pages inside plus cover. Page 2 Earl Boebert Page 3 Page 4 Page 5 A Model of Dodge Well, that didn’t take long. Two issues ago we printed the plans for Dodge, a neat little “plank on edge” catboat from the 1880’s. Member Al Borchardt built one to 3/8 scale. Not 3/8 inch to the foot, but 3/8 full size – the prototype was only fourteen feet, nine inches long. At 3/8 full size she’s just five and a half feet long, leading Al to describe her as “a hefty little craft in a great size for transport.” Here’s what Al said about building Dodge: When setting up the strongback and frames I put 2 large cuphooks between each station. The hull is planked with 5/32 thick cedar edge glued with Elmer glue. Rubber bands are slipped on the cup hook, over the plank and down to a frame corner or cloths pinned to the shear plank. I build my hulls to the inner keel. After sanding to the finish shape. its glassed with 1 oz cloth and west epoxy. Then the exterior keel and dead wood are laminated with epoxy. The cloth doesn’t have any sharp corner to lay down to and if something does nick the keel, water integrity is not lost. The mast is an arrow shaft with a cedar over lay. A turned hardwood fitting at the near bottom of mast. The Dodge boom is drilled oversize of the arrow shaft and cupped to swivel on the mast. The arrow shaft then rest in the mast step cup glued to the deck with a pan head screw in its center, to adjust the mast vertically for clearance of the boom. Not to be outdone, member Jeff Stobbe is building a Dodge to 12 inches to the foot – full size. Now all we need is a picture of Al’s boat sailing alongside Jeff’s.! Earl Boebert Page 6 Ben Bow William Atkin was easily the most prolific small boat designer in the first half of the twentieth century, accounting for nearly six hundred sail, power, and auxiliary vessels. In 1929 he designed this seaworthy little cruiser called Ben Bow. The design was evolved from the celebrated double-ended designs of Colin Archer, which in turn were derived from boats of the Norwegian lifeboat service, whose legacy goes back to the Vikings. It is rare to encounter a design which can be scaled down exactly and still sail well, but such is the case here. At a scale of one inch to the foot, a little Ben Bow would be about 28 inches LOA with a 9 3/4 inch beam and 5 1/2 inches of draught, displace a bit under ten pounds and carry 520 square inches of sail. A great little “windling” model, at home in the roughest of water. Earl Boebert Page 7 Yacht Sails This 1939 book is by Terence North, who was trained on the full rigged ship William Mitchell. It contains a wealth of information on traditional sailmaking, and was finished by his friends when he met with a fatal accident. The illustrations are by H.H.R. Etheridge, and are a delight. I have extracted here the section on sail terminology. While this follows U.K. practice, it is close enough to American terms to be useful. I’m sure all our members are salty enough dogs to know their raffee from a sprit, but just in case you want to brush up on your terminology we offer this short course. Earl Boebert Storm or Spitfire Jib The storm jib, which with the trysail is the most important sail in the ship, should be made of good flax canvas of a suitable weight dependent upon the size of the ship. Jib Jibs are triangular sails, usually set flying from the bowsprit end and forward of the fore-staysail. The are also sometimes set hanked [attached with rings] to a jib-stay. Jibs are not reefed, reduction of sail being effected by setting a smaller sail. The No. 1 jib is the largest and the general working sail. The No. 2 jib is smaller, made of slightly heavier cloth, and is set when there is too much wind to carry the first jib, but insufficient to call for the use of the storm sail. . Quadrilateral Jib I think that this sail was set for the first time in Endeavour, the America’s Cup Challenger for 1934. Page 8 Genoa Jib Jib Topsail The jib topsail is used in fair weather with the wind free, and will often stand on the wind if the breeze is steady and it is well sheeted. [This sail] has practically superseded the old balloon jibs, which could only be carried with free wind. Genoa jibs are meant for closehauled work, and are consequently made of considerably heavier and stronger canvas than was used for the balloon sails. Yankee Jib Topsail [This] is really a very large jib topsail for use in light winds, and would be replaced by the jib topsail when the breeze increased. Fore-Staysail This is the name of the triangular headsail of a yacht which is set on the forestay by means of hanks, and is often called simply the foresail or the staysail. Page 9 hoisted, it pulls away like a train, and there is a wonderful amount of satisfaction to be gained from looking at its good flowing curves and tugging sheet. Fisherman’s Staysail Double Fore-Staysail This sail was used with success by Monsieur Marin Marie in his yacht Windbelle II for the single handed passage made from Boulogne to New York. He records in his log a run of twenty-six days before the N.E. trades, during which time the helm was not touched. The fisherman’s staysail is generally used only with the wind free, i.e. reaching. Mizen Staysail (of a Yawl or Ketch) A triangular fore and aft sail… It sets with hanks on the mizen stay which runs from the mizen mast head to the deck… This sail has of late been coming into favor, in modern ocean-racing yawls, particularly in the U.S.A. Reaching Foresail No vessel should be without a reaching foresail, for in light to moderate winds it is a glorious sail. Its effect can be felt as soon as it is Page 10 Gaff Mainsail (Laced Foot) Bermudian Mainsail Sometimes known as a “leg of mutton” sail, longer on the luff than the foot. Gaff Mainsail (Loose Foot) The principal sail of a gaff rigged cutter, ketch, sloop, yawl or schooner… The angle that the gaff makes with the topmast should be about 35 degrees… The proportions which the foot, head, and luff of a well shaped cutter’s mainsail bear to each other are more or less relatively fixed. I have found from the perusal of many sail plans of gaff cutters that the proportion is relatively as follows. Taking the foot as a basis, and calling it “1,” the length of the luff is about.75 of this foot length, and the length of the head about.63 of it. Thimble Headed Trysail Used by a yacht when there is too much wind for a fully reefed mainsail. This is the most important sail in the locker and very often Page 11 the least cared for, owing, in many cases, to its infrequent use; when it is required, then it should be “all shipshape and Bristol fashion,” for the vessel’s very life may depend upon it… Its area should be approximately that of the close reefed mainsail, and it should be provided with one deep reef. Spritsail It is used exclusively as principal sail in the spritsail barges of the London River and is frequently seen in gunning punts and small fishing craft of the flat-bottomed type native to large enclosed harbours and estuaries. These boats are primarily pulling boats and only set sail with a fair wind and as the sprit sail is quickly set and stowed and does not entail the use of a lot of gear it has been found most suitable for the purpose. The Gaff Trysail In trying to claw off a lee shore the gaff trysail is to be preferred as it sets better, and has more driving power than the jib header. Dipping Lug Sail This is one of the old fashioned lug sails, and its particular difference from the “standing” and “gunter,” is in the dipping of the yard to the new lee side of the mast when going about. It is invariably set loose footed, the tack usually being fastened to an iron hook on the stern or just abaft of it. Jackyard Topsail This type of topsail is in common use, and is set in vessels having a pole mast. Where a tall topmast is carried there is no necessity for a topsail yard, the luff of one sail being laced to the topmast. Page 12 Jib-Headed Topsail Used off the wind and increases the after sail area. It can be set in a stiff breeze. It is probably the most useful type of topsail to have aboard, being the easiest to set and take in, and not requiring yards. It can only be used, however, in vessels which have a sufficiently long topmast. Parachute Spinnaker [This sail] is cut with a large amount of belly, and has been termed a “Mae West” spinnaker by American professional yachtsmen. Circular anti-wind-cushioning holes are sometimes cut it down the last. It is often set in large racing yachts, being practically confined to this type of vessel. Yard Topsail [This] is a very old-fashioned sail, and is not seen nowadays in yachts… All the London barges set a type of yard topsail although the yard in this instance is only 6 to 8 feet in length and is known as the “head stick.” Watersail This sail is seldom used these days. It is sometimes seen in use on Dutch barge yachts where it is used in fair weather when running and is laced to the mainsail boom… As far as I know, a watersail and a bonnet are two names for the same sail. Page 13 The following is an extract dealing with the raffee from Mr. Conor O’Briens book On Going to Sea in Yachts: –“I can’t praise the raffee too highly. It is easy to hoist if you haven’t got a foresail set as well; it comes down with certainty in any conditions; it pulls nobly four points off the wind if the sea is smooth enough to make such courses profitable, and it goes on pulling when you’ve rolled all the wind out of the fore-and-afters.” Terence North (1939) The Vintage 36 Inch Class Squaresail The sail is set when running, and in extended ocean cruising, when many days are spent running before the Trades — a time when fore and aft rig would be subjected to a vast amount of chafe and wear and when the headsails are of no practical use. There are several methods of rigging the gear for this sail, some yachtsmen preferring one method, some another. Many yachtsmen have discovered a particular method of setting the sail which best suits their vessel, some going so far as to proclaim it the only seamanlike way: for this reference however the adage “different ships different long splices” has much truth in it. The goal of the V36 Class is to encourage economical, easily transported, good sailing boats of traditional form. We hope to encourage beginning builders to “test the waters” with this class, so our provisional rules emphasize published designs while still leaving room for those who like break out the ducks and battens. As always, we ask skippers to interpret the rules in the “vintage spirit” and keep the “sea lawyer” microscopes in storage. We’ll test these rules for two years, and in2007 have a vote of registered owners to determine their final form. Please register your boats with the V36 Coordinator, Alan Suydam: 22347 Goldenrod Drive Great Mills MD 20634 and asuydam@peoplepc.com Provisional Class Rules Published Designs prior to 1970 Any of the follow- Raffee The “raffee” is a fine weather sail used when running, and is set over the squaresail… ing: The MYRAA 36 inch junior rule. This rule defines a “sharpie” very similar to John Black’s Starlet, for which we have plans and full building instructions. Any pre-1970 published design of 36 inch LOA or 25 inch LWL. Examples include Yankee III, Pirate, Chico II, and the Detroit 36 Inch Any pre-1970 design to the UK 36R Rule. This rule restricts the hull shape to one that will fit in a box 36 by 9 by 11 inches deep. Page 14 New Designs Hull 36 inches LOA including bumper and 9 inches maximum draft. Rig limited to 600 square inches, calculated using the same formula and restrictions as the VM rule. about your boat or boats and tuck it in the hull to be discovered by later generations. Earl Boebert Materials Limits For all designs, materials limited as in the VM Class. Final Comments These rules are very much a “work in progress,” and no skipper should be deterred from attending an event during 2005 and 2006 because they think they would be protested or disqualified on a technicality. Also, our experience with VM regattas tells us that theoretical boat speed of one design vs. another really doesn’t show up on the water because of the short courses we typically sail. So pick a design that you like and come join us at the next V36 event! Alan Suydam and Earl Boebert Bits of Oakum The Model Yacht is published three times a year by the U.S. Vintage Model Yacht Group. Copyright 1998 to 2005 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 for nonprofit research and educational purposes. Editorial Address: 9219 Flushing Meadows NE Albuquerque NM 87111 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 Southeastern Vice-President: Thom Mclaughlin Vintage M Class Coordinator: Charles Roden 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 New Plans We have acquired full-size plans for two John Black designs, Starlet and the 6 Meter Kiltie. We have offered a newsletter for some time which has the Starlet article and full-size patterns. The full size plans will be a help in planning radio layout. Plans alone, $25.00 postpaid to the masthead address. For Starlet, plans and the newsletter together for $30.00 postpaid. To help “jump-start” the V36 class we offer plans of Chico II including a sheet showing Alan Suydam’s radio installation for $30.00 postpaid. Document That Boat! The 2004 exhibit generated the usual number of requests to have boats identified and dated. It’s always a little sad to read an email that says “this was made by my father/ grandfather and I don’t know anything else about it.” So take a moment and write a note Page 15 Whirlwind Jr. Background Since the designs of the full-size J boats were tightly constrained by the Class rules, it is possible to apply the method used to model Yankee III to any of the J Class designs. The bulk of this method was developed by John Black in 1934: 1. Scale the hull to 1/42 size. This was chosen so the model would come out an even 36 inches. 2. Drop the keel to six inches draft. 3. Start with a 1/ 42 sail plan and multiply all linear dimensions by 0.9. Then reduce the foot of the mainsail further to 16 inches, yielding about 450 sq in of sail area and making the sailplan look taller. My modest contributions were a one inch wide hollow fiberglass keel to hold ballast and the batteries and a simplified “double-headed” rig. So the question then was, “what J to build next?” The obvious choice was Whirlwind, because she was built right beside Yankee and the Lawley yard in Neponset and launched the very next day. History Excitement ran high in yachting circles in the Fall of 1929 when three contenders for Defender in the upcoming America’s Cup races were announced: Enterprise, to be designed by Starling Burgess, Yankee, by Frank Paine, and Weetamoe, by Clinton Crane. There was much press speculation about a fourth “mystery ship” – this turned out to be Whirlwind. She was the only New York boat not developed under the aegis of the New York Yacht Club. One member of her syndicate had successfully raced a double-ended M Class1 boat, Istalena, designed by L. Francis Herreshoff, son of the celebrated Nathanael. Herreshoff stayed close to the successful hull design of Istalena, which was ahead of its time in many areas, including having the point of maximum beam well aft of the fashion of the time. The double-ended design enabled her to be the only J that carried a permanent backstay. Her syndicate got a late start, which lead an overworked L. Francis to specify a “composite” construction of mahogany planking over steel frames, because the other three J boats under construction had absorbed all the relevant metalworking metalworking materials and workers. While her hull was conservative in both form and material, her rig and other details bristled with innovation. She was plagued with problems during shakedown and the Defender trials. A particular point of difficulty was her steering gear. Never sailed up to her potential, she was broken up in 1935. Page 16 1. Classes under the Universal Rule were assigned letters, J being the largest and S the smallest. Istalena was 87 feet overall and 54 feet on the waterline. 1/2 Full Size Making a Sailing Model of Whirlwind To save space, I am only going to describe those areas where Whirlwind Jr. is different from Yankee III. Experienced builders will be able to work from the drawings and apply their own preferences for rig, radio layout, etc. Beginning builders are advised to work from the detail designs and advice given in the book. Rig All rig fittings, materials, are as described in the book. The sailplan is as shown. The only difference is the jumper stay, which is a “V” stay instead of the single strut on Yankee III. competitive skippers in the 1980’s and 1990’s. It’s certainly possible to carve a balsa hull – in fact, that’s the way the first Yankee III prototype was built. A planked hull is more traditional, but planking the kind of full-keel hull the J boats had is very difficult. The problem is the reverse curve at the garboard, the point where the fin meets the main body of the hull. The solution I used was inspired by the design of the late Ted Geary’s Pirate model, many of which have been constructed by students in Seattle. Geary used a hybrid technique where the lower part of the hull was carved and the upper part planked. This is done on Whirlwind Jr. by making a two inch wide keel laminated out of 1/4 inch balsa sheet. The outer laminations, or “cheek pieces,” are made smaller to save material and work. A slot is left where the fin is attached to simplify the process of hollowing. The hull and keel plans are 1/4 full size. To check your enlarging, the hull 1/32 Ply Deck Waterway 1/8 x 3/16 Spruce Toe Piece Sheer Strake Laminated From 1/8 x 3/16 Spruce Balsa Planking 1/4” Balsa Sheet Keel Laminations Deck Whirlwind had a narrow waterway, which scales out to just a bit under 1/4” wide at the point of maximum beam. Her deck was raised, so the toe rail is placed underneath rather than above as on Yankee III. Hull Since Whirlwind was, basically, a wooden boat, it seemed inappropriate to use hightech material such as I did with Yankee III. A cedar hull would be “iffy” with regard to weight, so the logical choice was fiberglass over balsa, a well-tried technique used by Page 17 1/4” Balsa “Cheek Piece” A typical hull section, showing the wide laminated keel. The deck is sealed with “Stick-Tak>” Page 18 Keel “Stub” 1/2” (2 Laminations) Wide 1/2” Spruce Center Block 11 10 9 8 6 Keel Ends of Center Slot To Ease Hollowing Top of Fin 7 Baseline 5 4 Plan 2 Edge of 1/4” “Cheek” Piece Profile 3 1/2” Spruce Center Block LWL 1 40” Above 36” Above’ 1.25 x 2.5” V Spreader 25” Above 1.5” Roach 1” Roach 20” Above 40.5 37.35 34 25 18.5 17 11.5 16 4.5 2 1/4 5 12.5 Page 19 should be 37.3 inches long. The section plans show the outside of the hull; subtract planking thickness to make the shadows. I planked with 1/8” balsa but 3/32 would probably work as well. Getting the sheer strakes right is a very important step, as the sheer line really determines what the boat looks like on the water. For Whirlwind Jr. I used the same technique as with Yankee III: curving the strakes in plan (top view) ahead of time by laminating them out of smaller strips, then springing them to proper profile on the hull, in this case on the shadows. exact shape of a plank is transferred from the hull to a board. It is particularly useful when fitting the garboard plank. Whirlwind is a good boat to learn it on, since it has such nice fair lines. There are two basic methods. One involves transferring a curve to a “spiling board” and then to a plank. This takes an extra step but can be more economical of material. The second, illustrated here, transfers the curve directly to the board which will become the plank. 1 Make sure you lay out the strakes to the inside of the planking, as shown in the crosssection diagram. The strakes fixed in place only at the ends and at two stations, No. 5 and No. 9. The distance from the baseline to the top of the strakes at each measured position is as follows: Stem 0.32 Station 5 0.80 Station 9 1.06 Stern 0.85 Leave room at the other stations to let the strakes spring to shape, and sight down them to make sure they lay fair. Don’t worry if you have to adjust the attachment points to get them there. As always, remember Alan Vaitses’ parting words in his classic textbook, Lofting: “A fair line supersedes any given measurement.” The planked portion of the hull is a simple, convex canoe shape which lends itself well to the planking technique called “spiling.” The first picture shows the hull before planking, with the wide keel set onto the “shadows,” or temporary frames. The angle of the photograph is from the stern forward. The laminated sheer strakes have been set in place. The stub keel sticking up and the notch forward of it will be used to align the foam keel which will be hollowed later. You can also see temporary alignment pieces which go up through the “slot” that will be used to hollow the keel after glassing. Don’t cut the ends of the keel the way I did — it was a mistake that had to be fixed later with filler blocks. 1. The first step in spiling is to lay a batten down the hull at the outer edge of the “floor,” or the flatter part of the hull. Let the batten lie naturally in a nice fair line. This line will be the outer edge of the garboard, plank. Mark where the edge of the plank goes with softtip pen on each shadow. Spiling Spiling is a basic technique of wooden boat building. It is the method whereby the Page 20 bevelling here and there to get tight. Then (not shown) copy the width of the plank at each station from the marks you made whey you first laid the batten on the hull. In the case of Whirlwind this will be very close to a straight line. 2 5 2. Lay a balsa board that is wider than the maximum width of the garboard plank along those marks. Set a calipers or divider to the widest distance between the edge of the keel and the edge of the plank. This may not always be at a shadow. 3 5. Subsequent layers, or “courses” of planks are done the same way: batten, distances, plot curve, cut and fit. This shows the second course. I got lazy and did the hull in three courses; it would have been better to have done it in four. Finishing the Hull The fin is carved from foam off the hull and given one layer of 2 oz glass before assembly. I used scrap foam left over from one of the Yankee III prototypes, but any insulating or any foam will do. 3. Now lay out and mark this distance from the keel onto the board at each station point. By doing this you are “sampling” the curve that must be put into the garboard plank for it to nestle tightly against the keel. 4 4. The next step is to lay this curve out on the board with a thin batten and pins. Trace with a soft-tip pen, being careful not to distort the curve shape when doing so. Cut carefully and lay against the keel. It should fit very accurately, requiring just a little sanding and The fore and aft ends of the fin are hollowed out to fit the mounts on the hull. The fore mount is rounded to accept the shape of the fin, and the aft is tapered. The fin is then mounted to the hull with CA glue. This method makes it easy to align the fin properly. Page 21 Longevity Here the foam has a distinct edge. It is waterproof and non-absorbent, so any water that seeps in through cracks or damage will have no effect. Balsa, on the other hand, will deteriorate rapidly if it gets wet. The hull has been roughly faired and covered with Micro-Fill in preparation for final fairing and glassing. The Micro-Fill will go on easier if you dampen the hull before rubbing it in. Wearing rubber gloves will shorten cleanup. Rub the filler into all the cracks, let harden well, then final fair with a hard block and 400 grit sandpaper. Long sweeping strokes, and as always sand diagonally and not directly fore and aft. The final hull, faired, glassed and with the sheer cut. All the mechanical details, etc., are the same as for Yankee III. Comparison With Glass Over Foam Having made two similar hulls by the traditional glass over balsa and the newer glass over structural foam techniques, it’s interesting to compare the two approaches. Weight Unsurprisingly, since the foam has the same density as balsa, the hull weights came out about the same at twelve ounces. The Book This is book that has all the construction details I left out of the article. Available from the masthead address for $30.00 postpaid. Special combination deal: the book plus the 2004 exhibit catalog for $40.00 postpaid. Strength Again, much the same. Ease of Working The foam gets a slight edge here, owing to the absence of grain and the ability to cut and shape in any direction. Of course, there’s a special pleasure in working in wood. Mess and Cleanup The trick of spraying yourself with antistatic (“Cling Free”) spray doesn’t seem to work with balsa shavings and dust. The foam dust doesn’t float as much and is easier to sweep up — if you keep the static under control. Page 22 Earl Boebert