strut is used to provide clearanc-e--~--'::;.:g pinnedstrutiSj be tween the back into mast jenny stay and roach stays rear edgel of the mainstrut. strut is 31/4" from mast mast is center to back raked back stay, note "0" . ; _ center of the mast is Illug- ged~ with waad--side stay thro hook to pick up headboard on . mainsail, 1/4"-0 screw i·i ~ fore stoy ~ \: stainless steel wire '. jib halyard " 1/2"0.d, jackline-- sail hooks hard wood top mast dural attach to this line. extends into 1/2" jib halyard and ·o.d. durol main the fore stay are ma It a bout 2". attached to the loop made by the o hook picks up jib headboard side stay sto through the i-'-A-_--:":(---J-_-14-,,0-, .., B- 2" K- 26" C- 2 1/2" L- 32" D- 3" M-37" E-33/4" N-40" F-41/2" - P-55" G-IO 3/4" 0-47" H-1I5/S" R-61" sail and mast dimen- L sions. sheets, halyards and note how the side stays attach to backstay-- irish linen the chain plates--the stays I or braided nylon. meet these about 2" rearward jackllne and all of the base of the most. I I other stays are vane gear used to steer the yacht I '. stainless slee I _ ~ fishing leader. after Ihe sails are set. it mounts on the stern near the rud- der post. rudder port is 3/16"i.d. tu 2" long and is flush with Ihe bottom plaflk and is 2" forward of the DELTA CLASS transom. EYE PLATE BICIIG YACHT HAROLD C. KETHMAN stay sai I hooks are dress hocks stainless spaced 5" apart, steel hook up hook. an .ails. most e~ralAl.' , . Plate 1 SITUATION AT THE held to deck qr mast OUTHAUL RACKS lower end of ma~,t is "FOREFOOT" OF THE With twa 1/4 -0 screws. slatted-- a 1/16 pin JIB--SHOWING THE "" is mounted through nut ARRANGEMENT OF slots are 3/8 to 1/2 apart the slot to prllvent THE JIB CLUB SWIVEL. • the mast from spiral line-wound around " ,#,,"" ""~ sliding an the the mast- holds the jack line close to the mast. ~~~\~6oJ..,j.I.\~\\ mast step. dural or brass ~~~~~\ q moat step is I 3" to 4" lono. ) side sta y mainsail attaches to a hook 1/16" mounted to bridle--note hole in mast. jib club-- maximum diameter of a wooden ~;:;: ""ClUb is 3/4". 3/8" - 0 brass screw used with ail fittings which fasten to the the lower portion of deck. th,i,s . as~embly is,,knawn as the kicking strap, the mainsail is tightened,or slack­ ened, by adjusting the turn­ buckle, this action varies the curvature, or "lift", of the sail. 3/8"-0 screws use 3/8" to 5/S" o.d, these are used to wooden dowel used to reinforce mast at base and gooseneck! tubing with a heavy wall. lighten or ad just holes (Ire larger than the SITUATION AT GOOSENECK & the stays, halyards diameter of the line and or sheets. they are KICKING STRAP--SHOWING NO SCALE are pitched inwards insure not used with wire. MOUNTING OF THE MAIN DRAWING 10 holding power. BOOM TO THE MAST. 3~ BOAT MODELS Left and Above: "Venus," the first of the Delta Class model yachts, pulls slowly away from the shoreline guided by its automatic steering mechanism-the vane gear. The large balsa feather acts as a weather vane' to hold the rudder true-to-course. Note the simple flowing lines of this double-end hull design. DELTA CLASS RACING YACHT by Harold C. Kethman Here's a low-cost, easy-to-build model racing' yacht that any average modeller can build quiCkly without ' special tools • If you've been looking for a compara­ Full-Size Plans are available from the into these pieces. Note that the inwales tively inexpensive, easy-to-build model author, as noted at the end of the article. and chine logs are inclined to one another racing yacht which retain.s the racing -make sure that this is taken into con­ featu.res and qualities of yachts built to BUILDING THE HULL: Start by cut­ sideration when angling the blocks. The the more complex M.Y.R.A.A. classes ... ting out the bulkheads, using the dimen­ stem block mounts on top of the batten if you want a model racing yacht which sions shown on Plate 2. Note that hal/­ backbone. Tack-glue these blocks on the is interesting to sail for both the novice bulkhead outlines are shown, for the left building board. and the veteran skipper .. your search sides only. Add the matching right sides is over! when drawing the bulkheads on 1/4" KEEL STRUT: Dra'IV a grid of 1" Even if you have to buy all the fittings, waterproof plywood. squares as shown at the bottom of Plate 2 rather than make them yourself, the total Cut out the bulkheads with a coping and plot the curve of the strut onto a sheet cost of the necessary materials for our saw. Don't try to short-cut the building of %" dural. Cut out the strut, using a yacht-including the vane gear, mahog­ process by eliminating the center cut­ metal-cutting blade in a coping saw any, glue, etc.-should be well within outs of the bulkheads-these are neces­ frame. After shaping the strut, drill the your means. And no whittling is required sary so the yacht can "breathe'," permit­ keel bolt and lead-flow holes. Use fine -no expensive special tools-no years of ting the inside of the hull to dry if water emery cloth to polish the strut and re­ laborious constructiori! There's one plank seeps in. move scratches and scars. on each side and two planks on the bot­ The yacht must be assembled upside­ tom, all over a simple framework sup­ down on a 52" x 2" x %" clear pine build­ LEAD TORPEDO: This is elliptical in ported by six bulkheads, with light bat­ ing' board. Note that the bulkheads are shape and circular in cross-section. Make ten-backbones spliced into a central keel mounted between wooden blocks. These a mold using two blocks of 14" x 4" x 11h" mount. And the design has been tested are beveled 2° as shown in Figure A, by clear pine. Mark the outline of the tor­ and proven successful over a period of making the bottom 1 / 16" narrower than pedo accurately on each half of the mold more than two years! the top. as the cavities must match when the What 'are you waiting for? Mount the blocks flush with the edge mold is closed. Gouge out the cavities to This model is only one of the many de­ of the bulkheads and tack them to the the contour of the torpedo, making both signs possible in a new class of model bulkheads (not to the building board) sides as equal as possible, and sand racing yachts, appropriately named after with I" brads. When these assemblies them smooth. and identified by the Greek symbol Delta have been mounted on the board, they Four V4" aligning pin holes are drilled, (an equilateral triangle), used in mathe­ will be inclined 88° aft (to the rear) . one through each corner of the mold. A matics and physics to denote a change. Next, mark the bulkhead locations on cut-out is required to seat the blocks Rating restrictions have been kept to an the building board, following the dimen~ around the strut. It is also necessary to absolute minimum-the major restriction sions shown in the half top-view on Plate cut out a pour hole and a series of small is ' on sail area, which is limited to 600 2. Then; drill holes in the board ' so that diameter vent holes so that the lead can square inches. The Delta Class was wood screws can secure the mounting be poured into the mold. evolved by Jim Dempsey, Bob Leopold, blocks to the board from below. (After Insert and center the keel strut and put and the writer-all members of the Long . the hull has been fully planked, the four aligning rods into the holes in the Island (N.Y.) Model Yacht Club. screws are removed) . mold to keep the unit from shifting. Then, Carefully check the Bill of Materials clamp the unit together with a large "C" and gather together the necessary ma­ STEM & TRANSOM BLOCKS: These clamp or in a vise. hogany, plywood and other lumber before are cut from pine or mahogany-the di­ Approximately eight pounds of lead are trying to begin construction. If you have mensions are shown on Plate 2 (inside 2A required to make the six pound torpedo. ' difficulty securing any of the materials and 3F) . Bevel all edges correctly as the Melt it in a steel or cast iron pot such as locally, check the sources of supply listed. planking and batten backbones must fair those used by plumbers. These have a BOAT MODELS 35 inwale / ioIIl:---------- ALL MATERIAL IS HARDWOOD OR MARINE PLYWOOD. DON'T USE BALSA! side view of .: : this hu II is not ·.·········.... shown as it is ".' . not necessary =UI "" "" to the COll- 1 .g.;;:: struction. ,.,'" this is a NO s..c.A1.E d r ow­ ing -- follow the dimensions! rudder post (2" 1/4"above top of rudder) ~-T--T-~r-~ BALANCED RUDDER Made from 24ST Dural eheet. DELTA CLASS DCIIG YACIT-U) LENGTH OVERALL _ 50 DESIGN BY: HAROLD C.