Chapter 2

Hulls

When you have obtained the plans for your ship model, your first job will be to construct the hull.

If your model is to be a replica of the original, its hull, above all things, must be carefully shaped according to the accurate hull lines given in the drawings. To do this in the quickest and easiest way, you must follow some standard method of procedure.

Of course, the most workmanlike process would be to build the hull of tiny ribs and thin planks like a real vessel. This, however, is a big undertaking and much too difficult for the average amateur. Besides, there are other and easier ways of obtaining the same effect.

Simplest of all standard methods of model hull construction is the "bread and butter”method of lifts. This particular method gets its name from the fact that lifts of wood, cut approximately to the various horizontal sections of the hull, are placed one on top of the other and glued together. When first assembled, the side of a glued-up "bread and butter”hull resembles a series of narrow steps.

Most ship model plans provide for building the hull by this particular method, but any ship model drawings can be adopted. In either case, your first step will be to measure the depth of the lifts, making them all the same, and buy wood of this thickness. If wood of the exact thickness is not obtainable, take a size larger and have it planed down. What may be still easier, however, is to redesign the lifts to suit the thickness of the wood you can get. To do this, mark the desired thicknesses on the body plan and from that plan make a new half-breadth plan by marking the widths from the body plan on a new set of construction lines. These construction lines, of course, must coincide with the vertical lines on the original sheer plan. Just what these various plans represent is shown in Fig. 1. In any redesigning of the lifts, be sure that the deck does not cut entirely through the top lift at any point.

If the plans you have do not show the lift method of construction, this same procedure can be followed in planning the lifts and developing a half-breadth plan to agree.

With the lumber on hand, your next job will be to transfer your half- breadth plan lines to the lifts so that they can be shaped and assembled. Take a piece of tracing paper and from the half-breadth plan mark the line center line, all the construction lines, and one pf the half-breadth lines (the to which the particular lift is to be cut). This will give you one half of the curve. Then turn the paper over and, with the center line and other construction lines coinciding, draw in the other half, making a closed curve.



Do this with all of the lifts, using the same construction lines throughout. However, after each lift line is completed, pin the tracing paper to the strip of wood that is to be used for that particular lift and transfer the outline and the construction lines by means of carbon paper. (See Fig. 2.)

Next, cut each lift to within about 1/16 in. of the outline and, finally, hollow out all but the top and bottom lifts. This can be done by marking on the bottom of each lift the outline of the lift below and cutting to within about 1/4 or 3/8 in. of that with a coping saw as in Fig. 3. An extra allowance of wood for the final finishing also should be left at both ends of each lift. Hollowing the center lifts not only makes the hull lighter but lessens its tendency to warp.

When the lifts all have been cut to size, you are ready to start assembling your hull. Most experts work from the bottom up, placing their bottom lift flat on a bench or table, and gluing on the next lift, lightly nailing it in place from the inside (Fig. 4) to hold it. When all the lifts have been built up, one on top of the other, clamp the entire hull with hand screws or place it in the improvised clamps shown in Fig. 8 of the preceding chapter.
Once the "bread and butter”lifts of your hull have been assembled, you are ready for the roughing and final shaping. However, do not pass over the cutting of your lifts lightly. The more accurate you are in cutting them to the exact lines of your plans, the easier it will be to get the finished effect that is necessary if your model hull is to look real.


FIG.-4-

For the final shaping, you will need a series of templates cut to the shape of the lines in the body plan (Fig. 5). Cut these from cardboard, tin, or thin plywood and mark on each the exact point where the joint of two center lifts will come. This will give you a reference mark that will allow you to hold the template at the right height. Also, mark the deck line carefully at the edge of each template.

In use, the templates are placed along the hull at their respective positions at right angles to the keel. The bottom edge of each template, of course, should coincide with the center line of the hull.
If the hull slopes considerably from the water line to the deck line, cut the templates vertically upward in a straight line neglecting the "tumble home,”as this slope is called. Then, later on, when the rest of the hull has been shaped, the extra wood above the widest part of the hull can be shaved down to the deck to agree with the tumble home.

Construction Lines

Tin, Plywood, Or Cardboard Template

FIG. 5

Side Block <- _

Another method that is often used in making a hull, especially on models such as galleons and other older types of ships having long beakheads and high poops, can be referred to as the "half-hull and centerboard” method. It consists of assembling the hull from two solid sides and a plywood centerboard. (See Fig. 6.)

It is merely a matter of sawing the centerboard to the outline given and cutting out the two sidepieces from either solid or built-up blocks. The sidepieces can be shaped at the start from rectangular blocks cut to the right length and width. Mark the construction lines on them all the way around. Then mark the greatest beam line on the top and cut down to this. On the vertical side, mark to the profile, including the sheer, and cut to these lines. The two sides, of course, must be cut right and left so that when they are placed on each side of the centerboard they will form asmooth, symmetrical curve. When the two halves have been completely shaped with the aid of templates, they are glued to the plywood centerboard.

Hulls for small models are sometimes carved from a single block. This method, while appropriate for anything under 12 or 14 in., is not particularly well suited to larger models. Large, smooth-grained blocks of wood are difficult to obtain and the weight of a single-piece hull would make it difficult to handle in the shaping and smoothing processes.

Although relatively new, another ingenious method of hull construction is fast gaining popularity with many model makers. Like the "bread and butter”method of lifts, it is simple and timesaving. It consists of jig-sawing all the sections or lifts from a single board, cutting them one within the other, and then telescoping them out to form a hollow hull which can be carved with the least possible work.
How this is done is shown in Figs. 7 and 8. For the purpose of illustration, a Chinese sampan or rowboat has been used as the model. The same method of construction, however, can be applied to any hull that does not require a long beakhead or a built-up poop. In this method, the hull is made almost entirely with motorized tools, mainly jig saw, sanding disk, drum sander, and rotary file. The same work, of course, could be done with hand tools with the exception of the jig-sawing which, because of the angular cut, really requires a machine.

Board Saw Table (Tilted)
	Pc-Clamp Nontilting Table-

 
While the final result is not unlike that obtained with the bread and butter method, this new jig-sawing process does not waste any wood. Also, it reduces labor; a single saw cut serving for both the inside of one section and the outside of the section below. Completed, the jig-sawed hull consists of layers, but instead of being glued face to face as in the bread and butter method they are glued edge to edge, the joints running vertically instead of horizontally.
In selecting the stock for a hull to be constructed by this method, be sure to obtain wood that is at least one and one-half times as thick as the lifts specified in the model drawings. To play safe, you can obtain lumber almost twice as thick. For example, if the finished lifts are laid out as 1/2 in. thick, the wood should measure in the neighborhood of 1 in.

Since the actual sawing will be done with the bottom of the plank uppermost, the lift lines you draw will, in reality, be the lower edges of the lifts.

For the actual cutting, the table of the jig saw must be set at a slight angle to the saw blade. If your jig saw is not of the tilting variety, a supplementary table can be made from a thin board and two wedge-shaped blocks as in Fig. 8. The correct angle will be equal approximately to the thickness of a saw cut.

To obtain just the right cutting angle to allow the lifts to telescope the desired amount may require some experimenting. It best can be obtained by taking a piece of wood the same thickness as your stock and cutting a circle in it with the table set at what you think is the approximate angle. Then, remove the inner piece and mark the required depth of the lifts. Finally, push it into the outer piece and check to see if it comes through to the mark when tight. If it does not, adjust the saw one way or the other and try again. Of course, a very slight allowance must be made for the lining of glue that will be needed in the joint. In judging the thickness of the glue, allow a very little for casein glue, a trifle more for liquid glue, and still more for carpenter's hot glue.

Any one lift can be made deeper than the rest merely by varying the angle of the saw. Simply remember that the greater the angle of the cut, the shallower will be the lift. Of course, the top lift will have the full thickness of the wood, but in the case of most hulls this will be an advantage as it will allow the additional stock needed for shaping the deck curve.

As in all jig-saw work, a starting hole will be required to receive the saw blade. However, if a jeweler's saw blade is used, the hole will be small and can be bored almost anywhere without showing in the completed hull. The hole, of course, should be drilled to agree with the angle of the saw cut. Each lift should be completely sawed out in one cut if possible. If the wood is too long, however, for the sweep of the saw frame, bore entrance holes at each end of the curve and saw halfway along from each hole on opposite sides. Then remove the wood with the saw blade, reverse it on the table, tilt the saw table the other way until the blade is again upright and can be refastened, and complete the sawing.
When all the lifts have been sawed out, mark the desired depth on each and push them through to see if they come to the marks. If they do not, a little sand papering here and there can be done to even matters.

When you are satisfied with the fit, brush your glue evenly on the outside edges of each lift, push them through to the depth marks, and set the hull aside to allow the glue to dry.

If the model you plan to build by this method has high-wall sides, it will be necessary to add a separate section as well as a deck to the top of your telescoped hull. Similarly, for any hull having sides that slope in (tumble home), a second series of lifts can be made tapering the other way, meeting the first at the widest water line.

With the exception of the "half-hull and centerboard”method of construction in which the hull is shaped in halves before assembling, there is one point where all other methods converge. That point is the final shaping. As already described, carefully shaped templates should be used in bringing the curves to their proper contours.

There are many ways of holding a rough hull while it is being shaped (Fig. 9). One method consists of screwing it bottom-side up to a suitable block that can be held in the vise. Another and more flexible method consists of screwing the hull bottom-side up to a separate supporting stick having octagonal ends which can be turned and clamped in any one of four positions in two vises of the machinist's type fastened to the outer edge of your bench. Or, if you have a regular wood vise, you can clamp it in that, shaping it from the center toward the ends. In the final shaping that requires continual shifting, it can be held between your knees in the same way that a shoemaker holds a shoe. When the sides have been shaped with whatever tools are available files, chisels, gouges, spokeshave, and round-bottom plane shave down the top of the hull block to within about 1/8 in. of the deck level. Then shave down from the fore-and-aft center line to the edges, giving the deck a slight, even crown. Before the hull is completely shaped, the forecastle head and poop pieces should be glued on.

The next step will be to place the stem, sternpost, and keel. These can be set in shallow rabbets or merely glued and nailed on. The important thing is to try out cardboard replicas of the pieces first to make sure that the hull sides approach them sharply and neatly. Any hollows or bumps should be removed before the actual pieces are set in place.

To make a bulwark, take a piece of thin whitewood or white pine about twice as wide as the depth required. Lay this along the side of the hull, fastening it temporarily with thumbtacks, and with a sharp pencil mark the outline of the deck. If the forward end is to flare out, the strip should be held in this position during the marking operation.

Cut the strip accurately to this line and, measuring from that edge, mark the right height and cut down almost to it. Then glue and lightly nail it in position, either in a rabbet or against the waterways as shown in Fig. 10. In some cases, it may be necessary to steam the forward end of the bulwarks to twist them into the required flare.

FIG . 10

If, as in many small models having no deck, the inside of the hull must be gouged out and smoothed, it will be necessary to devise some convenient method of holding the hull during the work. Of course, it can be clamped top-side up in your woodworking vise, but a better method is to construct a special jig for the purpose. Such a jig or clamp is shown in Fig. 11.
It consists of a base and two cradle-like jaws cut from scrap lumber, 1-in. stock preferred. One jaw is attached securely with glue and screws to one end of the base, while the other, identical in shape, is fastened to the opposite end with screws only so that it can be removed easily. The jaws are padded with strips of soft cloth or felt to protect the hull.

In use, the hull is slipped under the cradles and the removable jaw tightened. Then, a third, but smaller cradle-like block is wedged under the center of the hull to hold it firmly in place. For protection, this wedging block also is supplied with pads. The base of the clamp can be held in the jaws of your woodworking vise or braced against the bench stop.

When the shaping is completed, it will be well to make either a permanent or temporary base to hold the hull perfectly upright and horizontal before attempting to apply the bulwarks and other trim. A padded cradle support similar to the clamp shown in Fig. 11 can be used or, since a regular decorative support will be needed when the model is completed, the finished mounting can be used.

In preparation for the final painting of your hull, you can apply the ground coats and mark the water line, the latter being drawn in with pencil or scratched with a scriber (a sharpened nut pick will do) on the ground coat. How this is done is shown in Fig. 12.

First, a suitable block of wood is obtained. Since it is to serve as the supporting gage for the pencil or scriber, it should be thick enough to bring the marking point up to the desired height of the water line. When the proper thickness is obtained by planing, attach the pencil or scriber to the top surface of the block with staples. Be sure, of course, to keep the lower surface of the block perfectly flat.

Hull With Ground Coat Of Paint Applied


Using a square, the hull is then held in a true vertical position on a bench or table and the pencil (or scriber) and block moved around it in the manner of a surface gage. Line the square up with some true, vertical edge on the hull and hold it there during the entire marking operation. Of course, if the water line is higher at the stern, the bow of the model should be raised the required amount with a block.

If you are modeling a wooden ship of the type used around the middle of the nineteenth century, you probably will want to obtain the effect of copper sheathing below the water line. This can be done in two ways. You can apply actual copper to the hull or imitate it with copper paint and touches of green to give the effect of verdigris. The actual sheathing, of course, gives a more realistic appearance.

Generally, shim copper about .001 in. thick is used for model sheathing. Cut in strips equal in width to about one-third of the hull surface on each side, it can be shaped to the curves and fastened in place with glue. To obtain the effect of nail heads outlining the plates, you can mark the back surface of each strip with the improvised tool shown in Fig. 13. Simply mount the sprocket wheel taken from an old watch in a fork of metal supplied with a suitable handle. Then, before gluing each sheathing strip in place, run the wheel over the copper to form tiny rectangles. Full size, most sheathing plates are approximately 1 ft. wide and 3 ft. long, so you can arrange your marks accordingly to agree with the scale of your model.

To obtain the effect of verdigris on the sheathing, rub the copper lightly with a soft cloth soaked in a solution of strong vinegar to which a pinch of salt and a little household ammonia have been added. After allowing it to dry overnight, brush off the superfluous green that has formed and, using steel wool, polish the copper slightly at the bends and high points in the hull. Finally, to preserve the final effect, apply a thin coat of clear lacquer. Although a completely planked model is a difficult undertaking, the amateur can obtain the same effect by applying tiny external "planks”to the exterior of an ordinary carved hull. The small stock that will be required can be secured by dismantling several Japanese wall pockets of the type that can be purchased at almost any variety or notion store. Thin veneer cut into strips also can be used.,




The strips are glued and tacked with very small pins to the carved hull (see Fig. 14). Because of the differences in girth at the various points along the side of the hull, it may be necessary to taper the planks slightly where they approach the stem, sternpost, and keel. If the hull bends sharply at any point, it will be easier to force the strips into position if they are first soaked in hot water to make them pliable.
 
The steel plates of modern ships can be imitated in the same way by applying small rectangles of drawing paper to a carved hull. If small pins are used to hold the "plates”in place, they can be spaced in imitation of actual rivets.

After the hull has been painted, shallow lines can be cut in the deck with the toothed tool shown in Fig. I of Chapter I to represent the deck planking. On smaller models, the planks can be drawn in with a 4H pencil.

The deck then can be given a coat of thin varnish, but do not strive to get it too shiny.

In this general description of the various methods of hull construction, little has been said about the types of woods used. While a great deal depends on what woods you have available for the work, some varieties are better suited than others.
For the hull proper, clear, straight-grained white pine free of knots will prove the most satisfactory and easiest to work. For the smaller pieces such as the keel, stem, sternpost, and bulwarks, some harder wood gumwood is excellent will be stronger and less likely to give way after it has been fastened in place.

When cutting wood for a hull, always save the scraps and extra pieces. They will form excellent stock for making many of the deck parts and fittings later on in your work.

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