How to Build a Timber Jubilee
Setting Moulds in Place
Attaching the Planking
The purpose of this article is. to describe, with the aid of carefully drawn diagrams, the steps to be taken in building a Jubilee Class 18-foot yacht. This entails a description of materials and tools to be used, directions for the initial planning, and a sequence of diagrams with accompanying text. The diagrams are for use in conjunction with the official plans and specifications for a Jubilee, and cannot serve as a substitute for them.
Although building advice given here naturally concerns the Jubilee alone, much of it will apply to all types of small sailing craft, and amateur builders with: little previous experience will find in this article some very useful guidance for their future work.
The man who undertakes to build his own Jubilee has the satisfaction of knowing that he is building a yacht of sound, trustworthy design, proven in nearly fifty years of racing and pleasure sailing. It may be granted that a Jubilee is not a particularly simple boat for an amateur to build, but at least two dozen very successful Jubilees have been built by amateurs; and the thrill of building your own "Jube" is surpassed only by that of taking her out with a dozen of her sister yachts on a really hard day, when the crews of many other small craft are watching from the pier.
Plans and specifications for a Jubilee are obtainable from the Jubilee local controlling body in each State. Before you start building, make a detailed examination of any well-built Jubilee and ask the advice of a boat builder or a qualified amateur about any intricate or difficult points of its construction. A close study of the plans and specifications is also essential.
Because some timbers originally specified are hard to get, specifications have been amended to allow the use of almost any of the timbers now used in boatbuilding. Overleaf is the list of materials needed to build a Jubilee.
List Of Materials
Keel. -1 4877mm X 178mm X 64 mm (16' X 7" X 2 1/2") dressed, Jarrah, Spotted Gum or Blue Gum, etc.
Stem. -2 762 mm X 152 mm X 102 mm (2'6" X 6" X 4") dressed, Jarrah, Spotted Gum or Blue Gum, etc., or natural-grown crook of N.S.W. Ti-tree or equivalent.
Stern Knee. -1 457 mm X 178mm X 51 mm (1'6" X 7" X 2") Jarrah, Spotted Gum or Blue Gum, etc.
Sternpost. Off-cut from keel.
Plate Case Posts. -2 610 mm X 51 mm X 19 mm (2' X 2" X 3/4"), Jarrah, etc.
Planking. -2 305mm X 14mm (12" X 9/16"). Cut two planks. Kauri, Oregon, Maple or equivalent.
-2 2134mm X 178mm X 25 mm (7' X 7" X 1"), Kauri, Oregon, Maple or equivalent.
-2 2438 mm X 127 mm X 51 mm (8' X 5" X 2"), Kauri, Oregon, Maple or equivalent.
Gunwales. -2 5791 mm X 64 mm X 38 mm (19' X 2 1/2" x 1 1/2"), Oregon.
Plate Case. -2 1422 mm X 610 mm X 29 mm (4'8" X 24" X 1/8"), Red Pine, Oregon, etc.
Floor Bearers. -40 57 mm X 25 mm (2 1/4" X 1"), Oregon, etc.
Flooring. Off-cut from planking.
Bilge Stringers. -2 3353mm X 38 mm X 38mm (11’ X 1 1/2" X 1 1/2"), Oregon.
Carlins. -3 3048 mm X 44 mm X 44 mm (10' X 1 3/4" X 1 3/4"), Oregon.
Shelf. -2 1219 mm X 51 mm X 25 mm (4' X 2" X 1"), Oregon.
Tabernacle. -2 813 mm X 152 mm X 25 mm (2'8" x 9" X 1"), Oregon.
-1 1829 mm X 229 mm X 38 mm (6'X 9" X l 1/2")|
-1 1829mm X 152mm X 32 mm (6' X 6" X 1 1/4")|
-1 1524mm X 152mm X 25mm (5' X 6" X 1")|
-6 1219mm X 102mm X 25mm (4' X 4" X 1"), Oregon.
-1 2057 mm X 178 mm X 25 mm (6'9" X 7" x 1")|
-1 1524 mm X 229 mm X 25 mm (5' X 9" X 1"), Oregon, Kauri or equivalent.
Decking. -1 85344 mm X 102 mm X 16 mm (280' X 4" X 5/8"). T. & G. lining, Oregon or Baltic Pine.
Coamings. -2 3353 mm X 178 mm X 13 mm (11' X 7" X 1/2") planking material. 1. 838mm X 178mm x 13mm (2'9" X 7" X 1/2"). 9144 mm X 13 mm X 38 mm (30' X 1/2" X l 1/2") quad mould.
Chafing Battens. -2 5791 mm X 38 mm X 25 mm (19' X 1 1/2" X 1"), Jarrah.
Rudder. -1 1219 mm X 229 mm X 29 mm (4' X 9" X 1/8"). 1- 686 mm X 229mm X 29mm (2'3" X 9" X 1/8"). 2. 610mm X 178mm X 19mm (2' X 7" X 3/4").
Mast. 9449 mm X 102 mm X 89 mm (31' X 4" X 3 1/2" ). light Oregon or laminated Spruce.
Boom. 3810mm X 64mm X 64mm (12'6" X 2 1/2" X 2 1/2"), Oregon or laminated Spruce.
Crosstrees. -2 1067 mm X 64 mm x 25 mm (3'6" X, 2 1/2" X 1"), Oregon.
Deck Canvas. 5791 mm X 1829 mm wide X 339 g/m2 (6 1/3 yds. 72", 10 oz.) canvas.
Miscellaneous. 4.54 kg X 32mm(101b 1 1/4") copper nails for planking. 70. 76 mm (3") copper nails for gunwales and stringers. 2.72 kg 10 mm (6 Ib. 3/8") copper roves. 1.81 kg (4 Ib.) red lead to preserve all timber junctions.
Tools You Will Need
Panel Saw for general use.
Rip Saw for ripping the keel, planking, mast, etc.
Ball Peen Hammer for riveting.
Claw Hammer for general use.
Pair of Riveting Dollies for riveting.
G. Clamps 4 or more required, 200 mm (8") opening.
Bar Clamps 2 or more required, 1000 mm (3') opening. For planking the hull and general purposes.
Chisels 25 mm (1") and 10 mm (1/2"), for use in shaping the keel and stem.
Screwdriver for general use.
Brace & Bit for drilling the rivet holes in the stem and keel and centre plate base, etc.
Rule and Square 1000 mm (3 ft.)
Smoothing Plane to fit and dress the planks, etc.
Rabbet Plane for cutting the rabbet in the keel.
Throating Plane is needed to hollow some of the planking, so that this will fit snug with the ribs.
Spokeshaves for shaping the rudder and stem, and for general use.
Wheel Brace for drilling each copper nail position in the hull.
Laying Out Full-Size Pattern
First practical step in building a Jubilee is to make a full-scale draft of the entire hull, with its details, from the official plans.
Sheets of wall board or thick paper measuring 6000mm X 1200mm (18 ft. X 4 ft.) will serve for this purpose. A black pencil line drawn perfectly straight at the bottom of this full-scale plan will be your "base line". The stations are marked along this base line from the stem to the stern, and are drawn at right angles up from it. The heights ofthe keel from the base line are marked at each station, and the camber of the keel, shape of the stem and angle of the transom are then drawn on
Details of the stem, stern post and knees, and the rabbet of the stem and the keel must also be indicated.
Shaping Stem and Keel and Stern and Transom
Making use of the full-size drawing of the stem as a pattern, shape the stem post from a natural crook of suitable timber, or else construct the stem in two sections, scarphing and riveting these sections firmly together. Particular attention must be given to the angle of the rabbet in the stem, to ensure that it will fit accurately when the planking is attached to it, and will have no tendency to develop a hollow or a bluff bow.
It is advisable to leave the stem post full, so that it may be trimmed later to fair off in line with the planking. The junction of stem and keel needs careful attention, and reference to the full-scale drawing will give the correct angle of the stem scarph to fit the keel scarph. The angle of the rabbet at this spot also needs careful attention.
The keel is set out from a full-size drawing which you are advised to make from the full-size sections shown on the plan. It is advisable to have this checked by an experienced man before attempting the arduous work of shaping the keel and cutting the rabbet. This is done by ripping out the broad shape of the keel and hand-shaping the parts of the keel to conform with dimensions given on the plan. The rabbet is cut the length of the keel, with the exception of the few inches where the stern post is halved to it. A rabbet plane greatly facilitates this job. The keel is checked to receive the timbers and slotted for the centre plate, and a rabbet is run at an angle on either side of the keel at the top of the slot, to receive the plate case.
The angle of the sternpost to the keel is of great importance. Reference to the full-scale drawing you have prepared will give the angles to which the stem post knee and stern post halving, which is to fit the keel halving, should be cut.
The transom is marked out accurately from a full-scale pattern. The angle at which it is cut is determined by the direction of the planking meeting the transom.
Some form of foundation-or base must be made, on which the hull can be set up and built. This foundation must be quite rigid, for any movement caused by the great stresses during construction will throw the shape of the hull and keel out of their correct alignment. A large log or a beam about 6000 mm (20 feet) long, similar in dimensions to a telegraph pole, will do very nicely for this purpose.
Diagram 3 shows a method of constructing an effective base. A straight log or beam of 100 mm X 100 mm (4 in. X 4 in.) timber, about 5000 mm to 5500 mm (16 to 18 feet) in length, has 100 mm X 50 mm (4 in. X 2 in.) stumps firmly nailed to it, at intervals corresponding to the stations of the hull. These are rigidly braced, and the log and stumps are set solidly in the ground in horizontal position, at a depth of about 610 mm (two feet). The stumps should project above ground level 450 mm (18 in.) or so at the lowest point — that is the after end — to facilitate working on the lower parts of the hull.
A base line of taut cord, or a straight edge corresponding to the base line in the large-scale plan, is now set perfectly level between uprights at stem and stern. The stumps of this foundation are then trimmed to represent the camber of the keel, by measuring at each station the heights above the base line shown on the plan.
Laying The Keel
Having completed the job of shaping the keel, stem and stern post, the next job is to set these on to the foundation. The keel, having been shaped from a flat beam of wood, now has to be bent to conform to the camber shown in the plan. This is done with the aid of long 12 mm (½ in.) diameter bolts, passed through the plate slot and on to the cross-bracing of the foundation.
The stem and the sternpost are riveted to the keel with a liberal application of red lead at the junction of the scarphs. The transom is now attached to the stern post by means of the rudder gudgeon and several 76 mm (3 in.) brass screws or copper rivets.
Now we pass on to the vital stage of hull shaping and construction. And let the reader remember that the basic principles discussed in this article are applicable to the building of most small craft using a type of construction similar to that of the "Jube".
Unless it is possible to hire or purchase a set of correctly shaped Jubilee moulds from a boat builder or other reliable source, it will be necessary to construct these from the table of offsets shown on the official plans. In all there are six moulds, one at each station. A study of diagram 4 will give an idea of construction of the moulds, which can be made from 15 mm or 20 mm (5/8 in. or 3/4 in.) thickness of Oregon or other pine.
Setting Moulds in Place
The moulds are placed in position at their respective stations on the keel and are temporarily supported. Temporary gunwales of 50 mm X 25 mm (2 in. X 1 in.) hardwood are attached at the stem and are secured to each mould and to the transom by brackets. The moulds are trued, and a batten is attached along the centre line of the hull, to the top rail of the moulds and to the stem post and transom.
Having been attached to the keel, the moulds are now given rigid support, either from struts to the ground on each side or preferably by means of a solid overhead framing, as shown in diagram 4.
Attaching the Planking
Twelve or thirteen planks on either side is the usual number required to plank the hull. The centre mould should be spaced off around its edge, so that narrower planks are used where the sharpest curves occur in the hull. Alternate moulds and stem and transom are marked in the same manner.
It is important that this spacing of the planking be carefully considered. Keep a thin, narrow plank handy; you will find it of great assistance in this respect, and also as a template for establishing the shape of each plank to be fitted.
Keep in mind that each of the twelve or so planks must be shaped from a very narrow part at the stem, to broaden out as the beam increases, and then to taper off slightly to the stern. You must realise that narrow widths of planks must be used to take the sharper curves of the bilges. This will ensure a smooth rounded hull when the planking is planed up and sanded. It follows that on the flatter parts of the hull — that is, around the bottom and after quarters — wider planks can be used.
The first plank, or garboard, usually starts at the stem and keel scarph and is attached 50 mm or 75 mm (2 in. or 3 in.) below the tuck. A stealer fills the space between the garboard and keel rabbet. A second stealer is used at the tuck and is scarphed into the second plank. These stealers are hollowed out from 178 mm X 25 mm (7 in. X 1 in.) board and 127 mm X 50 mm (5 in. X 2 in.) board respectively.
The second plank, being first attached to the stem, follows the garboard until about 2100 mm (7 or so feet) from the stern post, where it fits the tuck stealer and finishes at the transom.
The rest of the planking is done in a similar manner on both sides of the hull, each plank being carefully fitted and attached first to the stem by 32 mm (1 1/4 in.) copper nails or brass screws, and then temporarily to each mould with very thin 38 mm (1 1/2 in.) iron screws, which are later removed, the holes being carefully plugged with wooden pegs.
Each plank when first fitted should be attached with the aid of clamps only, so that any adjustments can be made before finally attaching. The plank can then serve as a pattern for the corresponding plank on the other side of the hull.
To ensure that the ribs fit up snug with the planking, some of the planks taking the rounded form of the bilge must be hollowed slightly.
Ribbing the Hull
The next step is to rib the hull, and the simplest method of preparing the ribs for this job is to soak them first for several days and then boil them for 30 minutes in a 3000 mm (ten-foot) length of spouting or a similar trough, suitably supported over a fire.
The position and lay of each rib should first be marked by lines around the inside of the hull, with the help of a narrow strap of metal of 38 mm X 1.6 mm (1 1/2 in. x 1/16 in.) gauge. An electric drill is then used to drill the nail positions through the planking around the rib lines, staggering the nail positions on either side of the line about 6 mm ( 1/4 in.) from it; 32 mm (1 1/4 in.) copper nails are next pointed in these holes, ready to secure the ribs when they are steamed or boiled and set in their place.
Commence ribbing in the mid-section of the hull, working first aft and then forward, so that any ribs broken in the after section might be used as shorter lengths in the fore section of the hull.
One man should be employed inside the hull, to carefully "tread down" each steamed rib and set it in place, while another hammers the pointed nails through the plank and rib.
It should be mentioned here that difficulty may be experienced with the ribs at the tuck. If there is trouble at this point, it is suggested that a metal template, of 50 mm X 6 mm (2 in. X 1/4 in.) iron, bent to the curve the ribs have to take, be used to pre-bend the ribs under boiling water with the aid of small G clamps and a 1.6 mm gauge (1/16 in.) metal strap passed around this template.
When the ribbing of the hull is almost completed, the moulds are removed one by one and ribs replace each mould. Temporary braces are employed to hold the hull in its correct shape after each mould has been removed.
The temporary gunwales are now replaced by permanent ones. It is perhaps as well to pre-bend these around a tree-trunk or other object, and leave in a wetted state for several weeks before fitting into the hull. After attaching the gunwales on either side of the stem and breasthook, the bend of the gunwales around the shape of the hull must be taken gradually, making use of clamps, struts and a rope tourniquet at the after ends.
The gunwales are finally secured by 64 mm or 76 mm (2 1/2in. or 3 in.) copper nails, riveted through alternative .ribs and planking and knees or brackets at the transom.
Having correctly shaped the camber of the deck beams, first fit the widest one at the mast position.
The next to fit is that at the rear of the cockpit, and the carlines are set in to the position of the cockpit. The deck beams forward of the mast are then firmly fixed into the gunwales with dovetail joints, and so are those around the sides of the cockpit. Care must be taken to ensure that the correct sheer and camber in the deck line are followed from the plan.
The sail shelf forward, the chainplate shelves and the bollard may be fitted, and after these the tabernacle is fitted according to diagram 8, which shows clearly how this is done.
The stringers are next bent down to their positions around the bilges by temporary struts or braces, and firmly riveted through the hull with 64 mm or 76 mm (2 1/2 in. or 3 in.) copper nails at each alternate rib.
The centreboard case needs to be well and securely fitted, to prevent leaking due to the strains imposed on the centre plate. The slot for the centre plate should be sufficiently long and wide enough to allow for the end posts of the centre plate case to protrude through the keel and finish flush at the base of the keel.
Diagram 8 shows the rabbet which is run on an angle on either side of the centre plate slot in the keel, to receive the side boards of the plate case, which are angled to fit the rabbets in the keel. After laying a felt strip along the keel rabbet and red-leading the job, clamp the sides of the plate case down and rivet or bolt through the end posts to form the plate case.
Ten 150 mm long X 8 mm diameter (6 in. X 5/16 in.) copper rods are driven up slightly smaller holes through the keel into the plate case sides, to secure it firmly.
The thwarts are fitted next, the centre thwart passing across the rear of the plate case and attached to it to give rigidity. The after thwart is attached to cleats across several ribs, or to the after ends of the bilge stringers.
At the forward end of the plate case is a 76 mm X 76 mm (3 in. X 3 in.) bearer, which should be the first set in. At the rear end of the case, bearers should be fitted from the sides of the case to ribs on either side of the hull, at the height of the flooring according to plan. It is not practical to make a solid bearer at the rear end of the plate case, as this would interfere with the pump. A third floor bearer must be shaped to fit between ribs at the after end. Floor bearers are also attached to the entire length of the plate case, on either side of it.
The flooring is constructed from off-cuts of the planking, in three sections. One section on either side of the plate case, from the forward bearer to the rear of the case, and a triangular-shaped section aft of the plate case. The flooring boards are nailed or screwed to cleats, which rest on ribs at the outer sides, and on the bearers along the plate case sections. These cleats are required at every alternate rib only.
Having completed the fitting out of the interior, the next stage is to lay the decking planks and clamp and nail them to the deck beams. For this purpose 38 mm long (1 1/2 in.) galvanised or copper nails are used, with an application of red lead to the seams and tops of the deck beams. The decking is trimmed off neatly to the shape of the cockpit and made to fit with a watertight joint on top of the hull planking; finally it is dressed with a smoothing plane to a smooth camber, so that no ridges of the planking show through the canvas.
Laying Deck Canvas
Having first spread the canvas along the decking, draw a pencil line centrally, from 150 mm (6 in.) from the front to 150 mm (6 in.) from the after end of the cockpit. A cut is then made in the canvas along this line. The purpose of this cut is to allow the 1800 mm (72 in.) width of canvas to be stretched to take in the 2030 mm (6 ft. 8 in.) beam of the hull at the widest point.
After the canvas has been wetted thoroughly on the top surface, it is rolled up to facilitate handling.
Commencing at the bow, apply the canvas with thick paint (or some other suitable preparation) to the decking, unrolling the canvas straight in line with the hull as you apply the adhesive. A roller or squeegee is used to stretch and flatten any irregularities in the canvas as you proceed. The canvas is then pulled down 38 mm (1 1/2 in.) around the edges of the decking about the hull and cockpit, secured with 12 mm long (1/2 in.) copper tacks at 50 mm or 75 mm (2 in. or 3 in.) intervals, and trimmed off.
The coamings are now fitted around the cockpit by the use of 50 mm long (2 in.) brass screws screwed into the carlines, and into the deck beam at the rear.
The chafing battens are shaped and secured by 76 mm long (3 in.) brass screws passed through the planking and into the gunwales.
The 9500 mm X 100 mm X 90 mm (31 ft. x 4 in. X 3 1/2 in.) length of timber for the mast has to be sawn to as near the dimensions of the mast as possible.
To do this, first scribe a centre line up the entire length of the timber on one of the 90 mm (3 1/2 in.) faces. This will be the back of the mast. From the official plans, mark out on this face, at the points indicated, the widths of the mast equidistant from the centre line. The tapering shape of the mast is then drawn in with a thin black line. This marking out should be repeated on the opposite face, which will be the front of the mast.
With the mast lying on trestles at a convenient height, proceed to rip the long wedge-shaped offcuts from each side. From the plan, the tapering shape of the mast is drawn on both new faces thus obtained, to allow a long wedge-shaped off-cut to be ripped from the front side only. Using a jack plane or draw knife, proceed to form the mast to the pear-shaped sections shown in the plan, finishing off with a smoothing plane or spokeshave, and finally sandpapering.
After consulting the plan as to the sizes of the boom, it can be shaped mainly with a jack and smoothing plane. It is advisable to give both mast and boom a coat of oil and two or three coats of varnish.
The crosstrees are shaped from two 1067 mm X 64 mm X 25 mm (3 ft. 6 in. X 2 1/2 in. X 1 in.) lengths of Oregon, tapering from 64 mm X 25 mm (2 1/2 in. to 1 in.), and streamlined to an oval section, except for 229 mm (9 in.) or so next to the mast.
Painting the Hull
Having planed and sanded the hull to a smooth surface, the entire hull and deck should be painted with a red lead primer. Each nail or screw hole in the hull should then be neatly stopped with red or white lead and putty, or an approved stopping compound. After this has thoroughly dried, the primed hull should again be sanded and painted with a reliable flat white paint, after which two coats of gloss white or any other desired colour should be given to the hull. A light cutting with wet and dry sandpaper after all but the final coat is recommended. This painting procedure is followed on the inside of the hull also. The deck should receive two coats of paint.
All you have to do now is set up the rigging, full details of which are given in the official plans and specification booklet, and your "Jube" is ready for the water. Good sailing!