The Boy Mechanic Part 86

** Insulating Aluminum Wire [306]

Aluminum wire plunged hot into a cold solution of carbonate of soda becomes coated with a strong layer of oxide which forms an excellent insulator to electricity.

** How to Build an Ice-Yacht [307]

Condensed from an article by H. Percy Ashley in Rudder.

The plans and specifications shown in the ill.u.s.trations are for making a 400-ft. cla.s.s ice-yacht, having a double c.o.c.kpit to accommodate four persons. The weight of the persons in the forward c.o.c.kpit keeps the boat from rearing when in a stiff breeze. The forward c.o.c.kpit can be removed if necessary. The materials used are: backbone,

[Ill.u.s.tration: Ice-Yacht Complete]

white pine; center, clear spruce; sides, white oak caps; runner plank, ba.s.swood, b.u.t.ternut or oak; c.o.c.kpit, oak; runners, chocks, etc., quartered white oak. All the iron work should be first-grade Swedish iron, with the exception of the runners, which are soft cast iron.

It is not necessary to go into detail with the measurements as they are plainly shown in the sketches. The backbone is 37-1/2 ft.

over all, 12 in. in the center, 5 in. stern, 3-1/2 in. at the nose; width 4-1/2 in. All wood should be selected from the best grades, well seasoned and free from checks. In Fig. 1 is shown the complete ice-yacht with general dimensions for the sail and main parts. Other dimensions are shown in Fig-, 2. The backbone is capped on the upper and lower edges full length with strips of oak, 4-1/4 in. wide and 5/8 in. thick. The lengthwise side strips of spruce are 1-1/4 in. thick. The filling-in pieces placed between the side pieces are of seasoned white pine, leaving the open places as shown in Fig. 2. The parts are put together with hot glue and bra.s.s screws.

The runner plank should be placed

[Ill.u.s.tration: Details of the Ice-Yacht Parts]

with the heart of the wood up, so as to give the natural curve from the ice so that it will act as a spring. The plank is 16 in.

wide in the center, 14 in. at the ends; 4-1/8 in. thick at the center and 2-3/4 in. at the ends.

Details of the runners are shown in Figs. 3, 4, 5, 6, 7, 8 and 9.

The cast iron shoes are filed and finished with emery paper, making the angle on the cutting edge 45 deg. on both sides. The runners are 7-1/4 in. wide over all and 2-1/8 in. thick. The soft iron casting is 2-1/4 in. deep. The shoes are fastened by 5/8-in.

machine bolts. These are shown in Figs. 3 and 9. The rudder is 2-3/4 in. thick, 5 in. deep, including wood and iron, and 3 ft.

long. The cast iron shoe is 1-7/8 in. deep and fastened on with four 1/2-in. machine bolts. A bra.s.s plate, 1/4 in. thick, 2 in.

wide and 7 in. long, is inserted on each side of the runners as shown in Fig. 9. Three holes are drilled through for a 3/4-in.

riding bolt that can be shifted as desired for rough or smooth ice. The runner chocks and guides are 1-7/8 in. thick and 4-1/2 in. deep. They are set in the runner plank 1/4 in. and fastened with glue and 1/2-in. lag screws. These are shown in Figs. 6 and 7.

The aft c.o.c.kpit is stationary, while the fore or pa.s.senger c.o.c.kpit can be removed at will. Both c.o.c.kpits are the same size, 42 in.

wide and 7 ft. long over all. Each one has a bent rail, 1-1/2 in.

by 4 in., grooved 1/2 in. by 7/8 in. before bending. The flooring is of oak, 1-1/2 in. thick and 4 in. wide, tongue-and grooved. The forward c.o.c.kpit is made in halves and hung on the backbone with wrought-iron straps and bolts. These are shown in Figs. 41, 43 and 44. Two pieces of oak, 1/2 in, by 4 in. are fastened with screws to the flooring, parallel with the backbone in the forward c.o.c.kpit. The runner plank which pa.s.ses under this c.o.c.kpit gives it stability.

The spars should be hollow and have the following dimensions: Mast, 23 ft. 3 in.; heel, 3-3/4 in. ; center, 5-1/4 in.; tip, 4 in. ; boom 23-1/2 ft.; heel, 3-3/4 in. ;center, 4 in.; tip, 2-7/8 in. at ends; gaff, 12-1/2 ft.; center, 3-1/2 in.; ends, 2-1/2 in.; jib-boom, 10-1/2 ft.; 1-3/4 in. at the ends, 2-1/8 in. at the center. The gaff is furnished with bent jaws of oak, Fig. 17, and the main boom with gooseneck, Fig. 12.

Galvanized cast-steel yacht rigging, 5/16 in. in diameter, is used for the shrouds; jibstay, 3/8 in. in diameter; runner plank guys, 5/16 in. in diameter; bobstay, 3/8 in. in diameter; martingale stay, 1/4 in. in diameter. The throat,and peak halyards are 3/8 in. in diameter; jib halyards, 1/4 in. in diameter.

The main sheet rigging is 9/16-in. Russian bolt rope; jibs, 7/16-in. manila bolt rope, 4-strand; jib-sheet, 3/8-in. manila bolt rope. Four 1/2-in. bronze turnbuckles, Fig. 34, are used for the shrouds; one 5/8-in. turnbuckle for the jibstay and one for the bobstay; four 3/8-in. turnbuckles for the runner plank stays, and one for the martingale stay.

Two rope blocks for 3/8-in. wire rope, Fig. 10, are used for the peak and throat, and one block for the wire rope 1/4 in. in diameter for the jib halyard. Four 6-in. and one 7-in. cleats, Fig. 18, are used. The blocks shown in Fig. 11 are used for the main and jib sheets. The steering arrangement is shown in Figs. 4 and 5. The tiller is 3-1/2 ft. long; rudder post, 1-1/4 in. in diameter; shoulder to lower end of jaws, 4 in.; depth of jaws, 2-7/8 in.; length of post including screw top, 12 in. The rubber washer acts as a spring on rough ice.

In Figs. 13, 14, 15 and 16 are shown metal bands for the nose of the backbone, and Figs. 19, 20, 21, 22 and 23 show the saddles that fit over the backbone and hold the runner plank in place.

There are two sets of these. A chock should be sunk in the runner plank at each side to connect with the backbone to keep it from slipping sidewise as the boat rises in the air. The martingale spreader is shown in Figs. 24 and 25. Straps through which the ring bolts for the shrouds pa.s.s on the ends to fasten the turnbuckles for the runner plank guys are shown in Figs. 26 and 27. The bobstay spreaders are shown in Figs. 28, 29 and 30. In Fig. 31 is shown the top plate for the rudder post and in Figs. 32 and 33, the lower plate for same. The mast step is shown in Figs.

35, 36 and 37. Two positions of the jib traveler are shown in Fig.

38. The anchor plate for the bobstay under the c.o.c.kpit is shown in Figs. 39 and 40.

At the nose and heel the runner plank guys end in a loop. The bobstay has a loop at the nose and ends in a turnbuckle that fastens to the anchor plate under the c.o.c.kpit, aft. The shrouds, jibstay and martingale have loops at the masthead and are spliced bare over solid thimbles. The loops are finished in pigskin and served with soft cotton twine over the splice and varnished. The parceling is done with insulating tape. Serve the tiller with soft cotton twine and ride a second serving over the first. For the halyards hoisting use a jig shown in Fig. 46. The thimble shown in Fig. 47 is made by splicing the rope to the thimble at running part of halyard and pa.s.sing back and forth through cleat and thimble. This gives a quick and strong purchase and does away with c.u.mbersome blocks of the old-fashioned jig. The jib-sheet leads aft to the steering c.o.c.kpit. The main-sheet ends in a jig of a single block and a single block with becket. Be sure that your sail covers are large enough--the sail maker always makes them too tight. The c.o.c.kpit covers must fit tightly around the c.o.c.kpit rail. Many boats have sail and c.o.c.kpit covers in one piece.

The woodwork may be finished as desired by the builder. The dimensions of the sails are given in the general drawing, Fig. 1.

** Turning Lights On and Off from Any Number of Places [310]

This can be done by the use of any number of reversing switches such as

[Ill.u.s.tration: Wiring Diagram]

those shown at Band C. These are inserted between the two-way switches A and D. Turning such a switch up or down connects the four contact pieces either diagonally as at C, or lengthwise as at B. The diagram shows connection from A to D, when the lamps will be on, but by turning either of these four switches into its alternative position, shown by the dotted lines, the circuit will be broken and the lights extinguished. When this has been done, the circuit may be restored and the lamps lighted again by altering either of the four switches in exactly the same way, and so on.

It will be observed that a reversing switch used in this way practically undoes whatever is done by the other switches. In the accompanying diagram only two reversing switches are shown and the lights can be independently controlled from four distinct positions. Any number of reversing switches can be placed between the two-way switches A and D to increase the number of places from which the lights could be turned on and off.

--Contributed by J. S. Dow, Mayfield, London.

** How to Make an Electric Pendant Switch [310]

It is often desired to use a pendant switch for controlling cl.u.s.ters of incandescent lamps. When such a switch is not at hand, a very good subst.i.tute can be made by s.c.r.e.w.i.n.g a common fuse plug into a key socket and connecting the socket in series with the lamps to be controlled. In this way you get a safe, reliable, fused switch.

--Contributed by C. C. Heyder, Hansford, W. Va.

** Measure [310]

Never guess the length of a piece of work--measure it.

** Home-Made Water Motor [311]

The small water motor shown in the ill.u.s.tration is constructed in the same manner as a German toy steam turbine. The wheel, which is made of aluminum 1/16 in. thick and 7 in. in diameter, has 24 blades attached to it.

The lugs or extensions carrying the rim must be made from the metal of the wheel, therefore a circle 8 in. in diameter must be first described on the aluminum plate, then another circle 7 in.

in diameter within the first and then a circle for the base of the blades, 3-1/2 in. in diameter. Twenty-four radial lines at equal distances apart are drawn between the two smaller circles and a 1/4-in. hole drilled at the intersecting points of the radial lines and the innermost circle.

Centrally between each pair of radial lines and between the two outer circles, 1/2 by 3/8-in. lugs are marked out and the metal cut away as shown in Fig. 1. A 1/8-in. hole is then drilled in the center of each lug. Each division is separated by cutting down each radial line to the 1/4-in. hole with a hacksaw. Each arm is then given a quarter turn, as shown by the dotted lines in Fig. 2, and the lug bent over at right angles to receive the rim. The rim is made of the same material as the disk and contains twenty-four 1/8 in. holes corresponding to those in the lugs to receive bra.s.s bolts 1/4-in. long.

The disks PP were taken from the ends of a discarded typewriter platen, but if these cannot be readily obtained, they can be turned from metal or a heavy flat disk used instead.

The casing was made from two aluminum cake pans whose diameter was 8 in. at the base, increasing to 9 in. at the rim. The centers of these were located and a 1/4-in. hole drilled for the

[Ill.u.s.tration: Fig. 3]

shaft. The disks P are the same as used on the wheel. Six holes 1/8-in. in diameter were drilled through the flat part of the rims while the two halves were held together in a vise. Bolts were placed through these holes to join the casing when ready for a.s.sembling. One side of the casing was then bolted to two 4-in.