Raymond F. Yates

“ In this way the model engineer will be able to design and construct model steam-engines according to his own ideas and in accordance with the raw materials and miscellaneous parts he may find in his workshop. Unless the young mechanic is in possession of a very well equipped workshop, it is quite impossible to construct a steam-engine according to certain specifications. However, if he has in mind the fundamental principles of steam-engine design, he can go ahead and design his engine, for which he will have no trouble in machining or producing the parts that enter into its construction. ”

“ BEFORE taking up the construction of any of the model power boats described in this book, it will be well for the young boat-builder to become acquainted with such terms as buoyancy, displacement, center of gravity, etc. Knowledge of these subjects is more or less necessary if successful boats are to be made. Aside from this, they are terms that every boy who claims an interest in boats should understand.
"How does a steel boat float?" is a question that many boys ask. The reason they usually designate a steel boat is probably because steel is so much heavier than water. ”

“ But many things heavier than water can be [4] made to float if they are in the form of a boat. Concrete, for instance, is now being used in ship construction, and this substance, when reinforced with steel rods, is very much heavier than water.
Before learning how a boat floats, what is known as "specific gravity" must be thoroughly understood. Gravity is a force that is continuously "pulling" everything toward the center of the earth. It is gravity that gives a body "weight." Some substances are heavier than others ”

“ It is not practical to sail a model yacht dead before the wind without an automatic rudder. With the use of an automatic rudder the erratic movements shown in Fig. 148 can be entirely overcome. The action of the rudder is such that every time the boat leans over to luff up into the wind, the weight of the rudder causes it to swing out, and thus prevents her from losing her course. As a different type of rudder is required, according to the course in which the yacht is sailing, the weight should be adjustable if the same rudder is used. ”

“ The boiler coils, being red-hot, cause the water to flash into steam the instant it reaches them. By the time the steam has reached the opposite end of the boiler coils, it is no longer steam, but a hot, dry gas at a terrific pressure. From the boiler coils the steam passes into the steam-chest of the engine, and thence into the cylinder, where it expands, delivering its energy to the piston. ”

“ The influence of a sail upon the speed of a boat also increases with the angle that it makes with the center line of the hull. The more the yachtsman slackens out his sail, the more it will help the boat along. The reader will see that these two conditions interfere with each other, and therefore the trimming of the sails becomes a compromise. It is good for the young yachtsman to remember to sail his boat with the sails as slack as possible, as long as she keeps a good course. ”

“ Every body, no matter what its shape, has a center of gravity. The center of gravity is really an imaginary point in a body, at the center of its mass. Oftentimes engineers are heard saying that the [10] center of gravity of a certain object is too high or too low. Fig. 5 shows the center of gravity in a boat. If the center of gravity in a boat is too high (as illustrated in Fig. 6) the boat is said to be topheavy and unsafe. When a boat is topheavy or its center of gravity is too high, the boat is liable to capsize. ”

“ This is very simple to construct and makes a pleasing craft when finished. The hull is formed by two blocks. One of these forms the raised deck on the bow of the boat. The cabin is built up on this raised deck. It will be seen that the part of the hull that rests in the water is formed by one block. In building boats of this nature the constructor should be careful to keep them long and slender, since torpedo-boat destroyers are always of this type. They are high-speed craft, and their displacement must therefore be as small as possible. ”

“ If it is not the container should be gone over again with solder to assure its being leak-proof.
Before operating the engine with steam, it can be tested with a small bicycle pump through the opening for the safety-valve. The engine should turn over briskly at every stroke of the pump, providing it does not come to rest at "dead center." If it does come to rest at "dead center," where no air can enter the piston, the crankshaft should be given a little twist and the engine will then start. Before steam is applied it will be well to experiment until the engine runs with the air-pump. ”

“ The port-holes in the deck-house and hull are made by little pieces of brass forced in place over a small piece of mica. The life-boats, which are carried on top of the engine-house, are whittled out of a solid piece of wood and painted white. Life-boats are always painted white, regardless of the color of the boat upon which they are used. The life-boats are held by means of string and small dummy pulleys to davits made of heavy stovepipe wire. A rub-streak made of a piece of 1/4-inch square pine is tacked to each side of the hull just below the sheer-line. ”

“ There are probably few sports more interesting than that of model power-boat racing. The Central Park Model Yacht Club of New York city is one of the most progressive clubs in America, and its members not only have a sail-boat division, but they also have a power-boat division. ”

“ It must be remembered, however, that water is unlike a solid substance and it "gives." When a man places his oar against the bank and pushes it, the bank does not move, and all of the man's energy is used in starting the [44] boat. Water, however, does not remain stationary when the paddles push against it, and therefore all of the power it not utilized in moving the boat—part is used in moving the water. ”

“ The hull is made according to the built-up principle, and the constructor will have to cut his templates before attempting the shaping of the hull. Owing to the depth of the model, it will be necessary to use about ten planks. The plank that is used to form the bottom of the boat is not gouged out. Every other plank is gouged out with a saw and chisel. [93]
The bottom plank is shaped with a knife to conform to the lines of the boat. In building up the hull with the planks, they should first be smeared with glue, and when put in place a few brass brads should be driven in. ”

“ The trim of the sails will depend upon the wind. If the boat is to sail against the wind, that is termed "beating to windward"; with the wind is called "scudding." With the wind sideways it is called "reaching." If the boat is sailed with the wind blowing midway between one of the sides and the stern in such a way that it sweeps from one side of the stern across the deck, this is called "three-quarter sailing" in a "quartering" wind. A model yacht will continue for a great distance on a reach or while scudding ”

“ If there is one way in which a model-builder can destroy the appearance of a model boat, it is by using badly proportioned masts. The average boy seems inclined to use a mast of too great a diameter, which makes it out of proportion with the rest of the boat. It is better to have a mast too small rather than too large.
The method of producing railing is shown in Fig. 106. The same small brass rod that was used for the davits can be used for the rail stanchions. One end of the stanchions is hammered flat and drilled out. ”

“ The young boat-builder will readily understand that it would be very impractical merely to bore a hole in the hull of the boat to put the propeller-shaft through. In this way water would surely leak into the hull and the boat would sink in a short time. Some method must be evolved to keep the water out of the hull, and yet allow the propeller-shaft to revolve freely.
The propeller-shaft is arranged within a brass tube, as shown at Fig. 38. The brass tube should be about 1/8 inch larger in diameter than the propeller-shaft. ”

“ Cutting a model boat-hull from a solid piece of wood is by no means a simple or easy task, especially for beginners. Of course, after several hulls have been produced in this fashion, the worker becomes practised in cutting them out. ”

“ If the builder desires to increase the capacity of the pumps and install a more powerful boiler and engine, only one pump will be necessary. Otherwise the water will not be pumped from the hull very rapidly.
When the builder has finished the pump units, he should turn his attention to the remainder of the fittings. Two small cranes are made, and one is placed at each side of the hull. They are made of tin. The cab of each crane measures 21/2 inches high by 2 inches long by 13/4 inches wide. A small roof is fitted on, and a piece of wood fitted to the bottom to serve as a floor. ”

“ This type of hull is extremely easy to produce and it is capable of carrying a considerable load. However, it is not a good type to use for all kinds of boats. It makes a splendid little pleasure yacht or submarine-chaser, but for a torpedo-boat destroyer or a freighter it would not be suitable.
The young model boat builder is advised not to try to construct hulls from metal. This is a very difficult task even for the thoroughly experienced mechanic. Wood is much easier to work with and will produce the same results. ”

“ When a machine screw is turned around just once, it moves forward a certain distance, as a glance at Fig. 36 will show. The distance the screw moves forward will depend entirely upon the distance between the threads. The distance between the threads is called the pitch of the thread. If the threads are 1/32 inch apart, then the screw will move 1/32 inch every time it revolves.
If a propeller acts in the same way as a screw, then it too must have a pitch. The pitch, or the distance that a propeller will advance in one revolution, is measured in inches. ”

“ The D plank will be cut from the center of B, but will have to be shifted two sections forward.
Having transferred the various shapes from the drawing on to their respective layers, you saw out each carefully with a bow or a keyhole-saw, care being taken not to cut inside the lines. It is better to cut full, and trim down to the lines with a chisel or plane. A good deal of trouble can be saved by the expenditure of a few cents for having them machine-sawed, in which case ask the sawyer to use his finest-toothed saw. ”

“ The hull of this boat can be formed by two 11/2-inch planks. These will require a little hard work to cut out; but, on the other hand, the effort will be entirely justified by the pleasing appearance of the little craft that can be produced in this way. A bow and stern block to raise the deck are cut out and nailed in place, as shown. A cabin is also placed on the stern of the craft, and this is formed by a block with a piece of cigar-box wood placed on the top. The cigar-box wood should project a little over the edges to form a canopy. The center of the deck can be raised by a third block ”

“ A fine cord or string, well stretched and oiled, is attached [83] to the wheel and led through two screw-eyes on the deck. From this it is led through an opening in the coaming to a drum on the steering column, which is turned by another small wheel similar to that used on the rudder-post, but with a round edge. The steering column is merely a piece of 1/8-inch wire, held in place by two small screw-eyes fixed in the coaming and with a tube-brush soldered on to keep the wire in position. The drum is simply a hard-wood bushing driven tightly in place. ”

“ The jib-boom is slightly less than 1/4 inch parallel.
All spars should be treated with clear size and fine sandpaper before varnishing. This will prevent discoloring by the latter, and will also allow the India ink markings to be made, which latter will be a guide for the trimming of the sails.
In order that any yacht, model or otherwise, may be able to perform her best, it is essential that she should have well setting sails. In fact, in a model a badly setting sail will sometimes even be enough to prevent her going to windward at all. ”

“ If there is more than one mast, all the sails carried abaft the mainmast serve to turn the boat in the direction A. The work of sailing depends greatly upon the skill in balancing these two effects so that the boat will progress in a straight line. ”

“ This angle of the blades causes them to force water back as they cut through it when the propeller is revolving. This forcing of the water back tends to produce a forward motion of the propeller, and in this way the boat on which the propeller is mounted moves through the water. The propeller is [45] caused to revolve by a steam-engine, steam-turbine, or gasolene-engine, as shown in Fig. 35 . Longer boats have more than one propeller. A boat that has two propellers is called a twin-screw boat. A boat driven with four propellers is called a quadruple-screw boat. ”