To go into the subject of designing at any length is outside of the scope of our present work, but a short description of the method of drawing and tools used, will enable the beginner to do all the work necessary for a small boat, and will also serve to introduce him to a most fascinating employment for his leisure hours, the importance of which to the intelligent and progressive yachtsman or boat sailor is now generally admitted.
The amateur will require a drawing-board, which for canoe work need be only a smooth piece of white pine three feet long, one foot six inches wide, and three-quarters of an inch thick; the lower and left hand edges being straight and at a right angle to each other; a T square about thirty-six inches long, one or two triangles of wood, or better of hard rubber, a pair of dividers with plain and pencil points, several ship curves of various patterns, scales and splines. These latter are long flexible strips of wood or rubber, and are used for drawing curves. They are usually held in place by lead weights at short intervals, but an easier and cheaper way is to confine them by small pins driven into the board. The best scales are those printed on strips of bristol board, eighteen inches long, costing twenty cents each. They may be had with any desired number of parts to the inch. The most convenient scale for a canoe drawing is two inches to the foot (one-sixth full size), or one and a half inches, in which case a common two-foot rule may be used, each division of one-eighth of an inch on which will represent one inch. For the sail plan the scale may be one-quarter of an inch to the foot.
A good paper for working drawings is the "roll detail paper" which is strong, buff in color and may be had of four or five feet in width and of any length. Some drawing pins are also needed to fasten the paper to the board, or if it is to remain there for some time, small copper tacks may be used, as the square and triangle will work over them more easily. A few pencils and an India rubber will complete the necessary outfit, a drawing pen being added if the drawings are to be inked in when completed, as they should be. If much work is proposed a few more curves may be added, a pair of small spacing dividers, bow pen and pencil.
Three views are always used in delineating a vessel, as shown in Plate I. These are called the sheer plan, half breadth plan, and body plan. The sheer plan is a vertical section, lengthwise of the boat, showing the curve of stem and stern, the rabbet lines, the sheer or deck line a b c, and the buttock lines, as curved lines; and the water lines, Nos. 1, 2, 3, 4, and the frame lines, 1 to 13, as straight lines.
The half breadth plan shows the width of one side of the boat at the deck and at each of the water lines, these lines being curved (as well as the diagonals Nos. 1 and 2), the frame and buttock lines being straight. The body plan shows the cross section at every frame line or square station (1 to 13); also, the line of the deck, a b c, as it appears from a point directly in front of the boat. The lines in the right-hand half (1 to X) are the sections of the forward body, and those to the left (X to 13) the after body. The water lines, buttock lines and diagonals are all straight in this plan.
The general type of canoe being decided on, we will make out a table of dimensions for reference in drafting, as follows:
DIMENSIONS OF CRUISING CANOE
Length, over all 14 ft. Beam, extreme 30 in. Beam, at water line 29 in. Draft of water 7 in. Depth, water line to rabbet (distance fh) 5 in. Depth of keel 2 in. Freeboard, bow (distance a e) 11 in. Freeboard, midships (distance b f) 5 in. Freeboard, stern (distance c g) 9 in. Sheer at bow 6 in. Sheer at stern 4 in. Round (or Crown), of deck 3-1/2 in. Thickness of plank and deck 1/4 in. Keel, sided (thickness) 1 in. Keel, molded (depth) 2-1/4 in. Stem and stern, sided (thickness) 1 in. Rake of stern post 2 in.
With the paper stretched as tightly as possible, and the board on a table of convenient height before us, the light coming from the upper left hand corner of the paper, we first draw a base line, A B, near the lower edge of the paper and in length equal to 14 ft. on our scale, using the T square with its head held firmly against the left-hand edge of the board. Now starting at 0, the right-hand end of the base line, we lay off with the dividers 14 spaces of 1 ft. each, numbering them from 1 to 14 as in the drawing, and, shifting the T square to the lower edge of the board, we draw vertical lines at each point of division, or 15 in all, prolonging them sufficiently to cross the sheer plan above.
Now at a distance from A B equal to half the extreme beam, in this case 30/2 or 15 in., we draw a horizontal line. Leaving a little space between the upper limit of the half breadth plan and the sheer plan, we draw the base line of the latter, C D, and parallel to it, and at any convenient distance apart, the water lines, Nos. 1, 2, etc., drawing in first the load water line at a distance f h above C D, equal to 5 in.
The other water lines, one above and two below the load water lines, are spaced 2 in. apart as the most convenient division in this case. The middle buttock and bow lines, and any others that may be necessary, are now drawn in the half breadth and body plans, and the diagonals are also drawn in the latter.
To avoid confusion of the many lines necessary, it is well to draw these "construction lines," which are the frame work on which the drawing is constructed, in red; then when the drawing is completed, the water lines and diagonals in the half breadth plan are drawn in blue, the latter lines being broken, the former full. The remaining outlines are drawn in full black lines. The base line C D is supposed to pass through the lowest point of the hull of the boat, exclusive of keel, which point, in nearly all canoes, would be the bottom of the planking at midships, next the keel.
Having the paper laid off, we will begin with the sheer plan, laying off between stations 7 and 8 the least freeboard, b f or 5 in., making a small circle to mark the place. Now at the bow we measure up a e or 11 in. from the water line to the deck line, at the same time measuring in the width that our stem is to be, outside of the rabbet, 1-1/4 in.; and similarly at the stern, measure up 9 in. and in 1 in. to the points a and c. Taking a long spline, we will lay it on the drawing so as to pass through these three spots, confining it by lead weights or by small pins on either side of it at each point. If it does not take a "fair" curve without any abrupt bends, other pins or weights must be added at various points until it is true and fair throughout, when the line may be drawn in with a pencil.
Next the outline of the bow, bottom of keel and stern may be drawn in with a spline or the curves, and also the rabbet line, showing the ending of the plank. The height of the crown of the deck at midships may also be laid off, and the middle line of the deck drawn. The center line of the midship section is E F, the manner of finding its position being given further on, and on each side of it at a distance equal to half the extreme beam. the perpendiculars s s are drawn; then, using a small spline or a curve, the midship section is drawn, according to the taste of the designer, the line beginning at rabbet in the keel, and ending at the point b, which is, of course, as high above the water line as the corresponding point in the sheer plan. The midship section is completed by drawing in the other half, measuring with the dividers the breadths from E F on each water line, and transferring them to the opposite side, afterward drawing a curve through all the points thus found. The round of the deck may also be drawn in the body plan, joining the two extremes of the midship section.
Now proceeding to the half breadth plan we will first draw in the half breadth of the keel, stem and stern. In a keel canoe the breadths will be the same throughout, from 7/8 to 1 in., but in a centerboard boat the keel must be wider amidships, to allow room for the trunk. In this boat the width at the bow and stern is 1 in.. so we lay off 1/2 in. and draw a line parallel to A B, to represent the "half siding" of the keel, as it is called. The same distance is laid off on each side of E F in the body plan, being other views of the same line.
The keel being laid off, the half breadth at the deck is taken from the body plan and set off at X on the half breadth plan. The side line of the deck, of course, passes through this point, its ends meeting the side of the keel at the points a and c, the distances of these points from stations 0 and 14 respectively being the widths of the stem piece and stern post outside of the plankng. A spline is bent through the three points so as to give the desired fullness at bow and stern, and the "side line," or half breadth, on deck is drawn in.
The breadth on No.2 water line is now laid off at X and the endings of the line determined by squaring down from those points in the sheer plan where No.2 water line cuts the rabbet of bow and stern to the siding of the keel in the half breadth plan. To test it we will run in some of the intermediate sections in the body plan, beginning with No. 4.
Three points of the water line are now determined, and to obtain others we refer to Table I. in the Appendix and find first, that in most of the canoes there described the midship section is placed at about the middle of the loadline, which in our boat would be 2-1/2 in. aft of Station 7, the length on loadline being 13 ft. 4-1/2 in., the fore body being 6 ft. 8-1/2 in. and after body 6 ft. 8 in. An inspection of the tables shows that the length of the "middle ordinate" (k l) in canoes of a medium type is about 37 per cent of the beam at the water line. Taking 36-1/2 per cent of 29 in. we have 10-1/2 in. as the half breadth at the middle of the fore body.
For purposes of comparison of the various canoes, a dividing buttock and body line is also used, being drawn in the body and half breadth plans, midway between the center and the extreme beam. The distances (rs-tv) of the intersections of this line with the load water line, afford a comparative measure of the degree of fullness of the boats, which for the bow ranges from 29 to 47 per cent. of the length of the fore body, and for the stern from 25 to 46 per cent. of the after body, the larger fraction, of course indicating a finer boat. For the fore body we will take 36 per cent as an average of cruising boats, then 36 per cent. of 6 ft. 8-1/2 in. = 2 ft. 6 in., which, laid off along the bowline from the fore side of the stem at water line, gives a point on the water line, and similarly, taking 40 per cent. (a rather large figure, but the boat in question has a very fine run) we have 40 per cent. of 6 ft. 8 in. = 2 ft. 8 in., which is laid off from the after side of stern at w l With these five points given a spline is readily set and the water line drawn in.
Turning now to the body plan (the right hand side of which represents the frames of the fore body, and the left those of the afterbody) the sheer or deck line, a b c, is drawn. The T square is laid across the board at the height of the stem; a in the sheer plan is squared across to the half-siding of the stem at a in the body plan, and similarly the heights at Stations 2, 4, 6, are squared in. Now the half breadth at Station 6 is taken from the half breadth plan with the dividers and set off to the right of E F at the proper height, then 4 and 2 are treated in the same manner, after which a curve is drawn from X through the spots to a, showing the deck line of the port side of the canoe, as it appears from a point directly in front, after which the line is drawn in the after body in the same manner. Of course this line gives the upper endings of all the frame lines, 1 to 13.
Only every other one of these is drawn in, the moulds thus being 2 ft. apart, but by laying off the stations 1 ft. apart, the bulkheads, masts, etc., are more easily located.
The lower ends of all frame lines will be on the side line of keel in body and half breadth plans, the heights being taken along the rabbet at each station in the sheer plan. Stations 4 and 10 are now completed, the breadths on the water line being transferred from the half breadth to the body plan, and curves drawn through the three points in each frame thus obtained.
Now the remaining water lines, Nos. 1, 3 and 4, may be drawn in the half breadth plan, their endings being found by squaring down from their intersections with the rabbet in the sheer plan and the breadths at 4, X and 10 being taken from the body plan. When all the water lines are fair, the frame lines at 4 and 10 being altered slightly, if necessary, to correspond, the remaining stations, 2, 6, 8 and 12, may be completed.
The design is now ready for the final fairing, for which the "diagonals" No.1 and No.2 are drawn in the body plan. These lines should be so drawn as to intersect all the frame lines at as near a right angle as possible. The distances along the diagonal from the point i to the intersection of each frame line, are taken off in turn, and laid off on their corresponding stations in the half breadth plan, and a line is drawn through the points. If the line is unfair it must be altered, the corresponding points in the water and frame lines being changed at the same time, until all coincide, the breadths and heights of every intersection being the same in all three plans, when it may be assumed that the drawing is fair.
The endings of the diagonals are found by squaring across from the points in the body plan where they cross the siding of stem and stern to the rabbet line on stem and stern in the sheer plan, and then squaring down these points to the siding in the half breadth plan. The diagonals maybe laid off in two ways, either an "expanded," as already described, or a "level" diagonal, in which the distances from E F in the body plan to each intersection are measured horizontally as g d.
As an additional test of fairness other "buttock" lines may be run in. These are drawn in the body and half breadth plans, parallel to the center lines, and are transferred to the sheer plan by taking the height of each intersection in the body plan and setting it off on the corresponding station, the curve being drawn through the "spots" afterward. The endings of the buttock line are found by squaring up from the points in the half breadth plan where they cross the deck line, to the deck line in the sheer plan.
The process of "fairing" maybe considered as completed when all the curved lines arc true and fair. and the heights and breadths of every intersection are the same in each of the three plans.
This completes the "construction drawing" from which the calculations, if any, are made. Plate II. represents the completed "working drawing" of the same canoe, showing dimensions of keel, ribs, etc., and the position of all fittings. This may be a separate drawing, or the details may be added to the "construction drawing," after which all lines are inked in, as before directed.