The Boy Mechanic Part 117

** How to Make a Cruising Catamaran [423]

A launch is much safer than a sailing boat, yet there is not the real sport to be derived from it as in sailing. Herein is given a description of a sailing catamaran especially adapted for those who desire to sail and have a safe craft. The main part of the craft is made from two boats or pontoons with watertight tops, bottoms and sides and fixed at a certain distance apart with a platform on top for the pa.s.sengers. Such a craft cannot be capsized easily, and, as the pontoons are watertight, it will weather almost any rough water. If the craft is intended for rough waters, care must be taken to make the platform pliable yet stiff and as narrow as convenient to take care of the rocking movements.

This catamaran has been designed to simplify the construction, and, if a larger size than the dimensions shown in Fig. 1 is desired, the pontoons may be made longer by using two boards end to end and putting battens on the inside over the joint. Each pontoon is made of two boards 1 in. thick, 14 in. wide and 16 ft.

long, dressed and cut to the shape shown in Fig. 2. Spreaders are cut from 2-in. planks, 10 in. wide and 12 in. long, and placed 6 ft. apart between the board sides and fastened with screws. White lead should be put in the joints before turning in the screws. Cut the ends of the boards so they will fit perfectly and make pointed ends to the pontoons as shown

[Ill.u.s.tration: Details of the Pontoons]

in Fig. 3, and fit in a wedge shaped piece; white lead the joints and fasten well with screws.

Turn this sh.e.l.l upside down and lay a board 1/2 in. thick, 12 in.

wide and 16 ft. long on the edges of the sides, mark

[Ill.u.s.tration: Completed Boat]

on the under side the outside line of the sh.e.l.l and cut to shape roughly. See that the spreaders and sides fit true all over, then put white lead on the joint and nail with 1-3/4 -in. finis.h.i.+ng nails as close as possible without weakening the wood. Slightly stagger the nails in the sides, the 1-in. side boards will allow for this, trim off the sides, turn the box over and paint the joints and ends of the spreaders, giving them two or three coats and let them dry.

Try each compartment for leaks by turning water in them one at a time. Bore a 5/8-in. hole through each spreader in the center and through the

[Ill.u.s.tration: Crosspiece and Rudder Details]

bottom board as shown. The top board, which is 1/4-in. thick, 12 in. wide and 16 ft. long, is put on the same as the bottom.

After finis.h.i.+ng both pontoons in this way place them parallel. A block of wood is fastened on top of each pontoon and exactly over each spreader on which to bolt the crosspieces as shown in Fig. 4.

Each block is cut to the shape and with the dimensions shown in Fig. 5.

The crosspieces are made from hickory or ash and each piece is 2-1/2 in. thick, 5 in. wide and 6-1/2 ft. long. Bore a 5/8-in.

hole 3 in. from each end through the 5-in. way of the wood. Take maple flooring 3/4 in. thick, 6 in. wide, 74-1/2 in. long and fasten with large screws and washers to the crosspieces and put battens across every 18 in. Turn the flooring and crosspieces upside down and fasten to the pontoons with long 5/8-in. bolts put through the spreaders. Put a washer on the head of each bolt and run them through from the under side. Place a thick rubber washer under and on top of each crosspiece at the ends as shown in Fig.

4. This will make a rigid yet flexible joint for rough waters. The flooring being placed on the under side of the crosspieces makes it possible to get the sail boom very low. The sides put on and well fastened will greatly a.s.sist in stiffening the platform and help it to stand the racking strains. These sides will also keep the water and spray out and much more so if a 12-in. dash is put on in front on top of the crosspiece.

The rudders are made as shown in Fig. 6, by using an iron rod 5/8 in. in diameter and 2 ft. long for the bearing of each. This rod is split with a hacksaw for 7 in. of its length and a sheet metal plate 3/32 in. thick, 6 in. wide, and 12 in. long inserted and riveted in the split. This will allow 3/4 in. of the iron rod to project from the bottom edge of the metal through which a hole is drilled for a cotter pin. The bottom bracket is made from stake iron bent in the shape of a U as shown, the rudder bearing pa.s.sing through a hole drilled in the upper leg and resting on the lower.

Slip the top bracket on and then bend the top end of the bearing rod at an angle as shown in both Figs. 6 and 7. Connect the two bent ends with a crosspiece which has a hole drilled in its center to fasten a rope as shown in Fig. 1.

Attach the mast to the front crosspiece, also bowsprit, bracing them both to the pontoons. A set of sails having about 300 sq. ft.

of area will be about right for racing. Two sails, main and fore, of about 175 to 200 sq. ft. will be sufficient for cruising.

--Contributed by J. Appleton, Des Moines, Iowa.

** Alligator Photo Mounts [424]

Rough alligator finished photograph mounts will not receive a good impression from a die. If a carbon paper is placed on the mounts before making the impression, a good clear imprint will be the result.

** How to Attach a Sail to a Bicycle [425]

This attachment was constructed for use on a bicycle to be ridden on the well packed sands of a beach, but it could be used on a smooth, level road as well. The ill.u.s.tration shows the

[Ill.u.s.tration: Bicycle Sailing on a Beach]

main frame to consist of two boards, each about 16 ft. long, bent in the shape of a boat, to give plenty of room for turning the front wheel. On this main frame is built up a triangular mast, to carry the mainsail and jib, having a combined area of about 40 sq.

ft. The frame is fastened to the bicycle by numerous pieces of rope.

Sailing on a bicycle is very much different from sailing in a boat, for the bicycle leans up against the wind, instead of heeling over with it as the boat. It takes some time to learn the supporting power of the wind, and the angle at which one must ride makes it appear that a fall is almost sure to result. A turn must be made by turning out of the wind, instead of, as in ordinary sailing, into it; the boom supporting the bottom of the mainsail is then swung over to the opposite tack, when one is traveling at a good speed.

** Removing Iodine Stains [425]

A good way to chemically remove iodine stains from the hands or linen is to wash the stains in a strong solution of hypo sulphite of sodium, known as "hypo," which is procurable at any photographic-supply dealer's or drug store.

There is no danger of using too strong a solution, but the best results are obtained with a mixture of 1 oz. of hypo to 2 oz. of water.

** Drying Photograph Prints without Curling [425]

Having made some photograph prints at one time that I wanted to dry without the edges curling, I took an ordinary tin can and a strip of clean cotton cloth, as wide as the can was long, and wound it one turn around the can and then placed the prints, one after the other, while they were damp, on the cloth, face downward, and proceeded to roll the cloth and prints quite close on the can. I then pinned the end of the cloth to keep it from unwinding and set the whole in a draft for drying.

The curvature of the can just about

[Ill.u.s.tration: Rolling Up the Prints]

counteracted the tendency of the coating on the paper to make the prints curl and when they were thoroughly dried and removed they remained nice and flat.

--Contributed by W. H. Eppens, Chicago.

** Piercing Gla.s.s Plates with a Spark Coil [426]

Anyone possessing a 1-in. induction coil and a 1-qt. Leyden jar can easily perform the interesting experiment of piercing gla.s.s plates. Connect the Leyden jar to the induction coil as shown in the diagram. A discharger is now constructed of very dry wood and boiled in paraffine for about 15 minutes. The main part of the discharger, A B, is a piece of wood about 6 in. long and to the middle of it is fastened a wood handle by means of one or two wood screws. A binding-post is fastened to each end of the main piece or at A and B as shown in the diagram.

[Ill.u.s.tration: Puncturing Gla.s.s Plates]

Two stiff bra.s.s wires of No. 14 gauge and 6 in. long, with a small bra.s.s ball attached to one end of each, are bent in an arc of a circle and attached one to each binding-post. A plate of gla.s.s, G, is now placed between the two bra.s.s b.a.l.l.s and the coil set in action. The plate will soon be pierced by the spark. Larger coils will pierce heavier gla.s.s plates.

--Contributed by I. Wolff, Brooklyn, N. Y.

** A Home-Made Still [426]

Remove the metal end of an old electric light globe. This can be done by soaking a piece of twine in alcohol and tying it around the globe at the place the break is to be made. Light the string and after it is burned off, turn cold water on the globe. The result will be a smooth break where the string

[Ill.u.s.tration: The Complete Still]

was placed. Purchase a piece of gla.s.s tubing from your druggist and secure a cork that will fit the opening in the gla.s.s bulb.

Bore a hole in the cork the right size for the gla.s.s tube to fit in tightly. If you cannot get a gla.s.s tube with a bend in it, you will have to make a bend, as shown in the ill.u.s.tration, by heating the tube at the right place over an alcohol lamp and allowing the weight of the gla.s.s to make the bend while it is hot.