Page:Popular Science Monthly Volume 91.djvu/487

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Popular Science Monthly

��471

��An Outboard Motor Made of Pipe and Fittings

A SERVICEABLE and satisfactory out- board motor for a rowboat can be con- structed from a second-hand motor-cycle engine and ordinary pipe and fittings. Either the one-cylinder or a "twin" motor can be used, the only difference being in the mounting, which can be worked out by an amateur mechanic.

While the stern transoms of rowboats vary somewhat in size, the dimensions herein given will suffice for the average boat. Any increase or decrease in the length of the upright supporting the motor can be adjusted by varying the length of one of its sectional parts, as shown in the drawing.

There are two essential parts to its con- struction; the motor and pro- peller frame and the supporting board. Sections A, B, and C are made of i^-in. pipe. The parts D and E are the same size cross tees while F is a \ x /i-\n. coupling with a J/£-i n. threaded opening in the side at G. Thetotaldistance from the flange H to the bottom of E should be sufficient to im- merse the pro- peller-blade at least 3 in. under water, and the distance from G to the center of E must be at least 6 inches.

The propeller / should be not over io in. in diameter and of shallow pitch, to allow for the usual high speed of motorcycle engines. This is connected with a tool steel shaft revolving in the proper bushings in E. The other end of the shaft carries a large sprocket wheel /.

The rudder hanger K is made of 3^-in piping by means of two straight pieces and an elbow. Fit the lower end with a tee to receive the bottom rudder-peg. A cor- responding piece of 3^-in. pipe is threaded into G.

Thread a small hole in one side of E and

���The parts in detail for making and attaching a motor- cycle engine to a rowboat for an outboard motor

��fit with a thumbscrew, then bore a 3^-in. hole about 2 in. under the flange on A and through the side of the pipe.

The mounting of the motor must neces- sarily be left to the builder, as each of the varied types and makes of motors must be mounted in its own way. The semi- circular strap shown in the drawing can, however, be adapted to several different standard makes. In any case be sure that the small sprocket M is lined up with / and that the crankshaft is long enough and pinned, to accommodate a starting handle. The rudder N can be cut out of heavy galvanized sheet iron and riveted to the rudder rod 0. This rod extends up as far as the base of the motor and is connected with the tiller by an elbow. The tiller is swung off at an angle so that it turns either way to clear the motor ancf frame.

Connect the two sprockets with a light motorcycle chain and cover well with heavy grease.

Thesupporting board can be made of a piece of heavy oak 18 in. long and 12 in. wide. Curve the top edge to con- form with the curve on the edge transom.

Have a black- smith make two heavy iron brack- ets P and Q and fit the short ends with thumbscrews as shown. Bolt one bracket to each end of the board, counter- sinking the bolt-heads on the underside. The smaller brackets, R and 5 should be sufficiently heavy to hold the motor and frame by means of a steel pin passing through the holes in the ends of the brackets and the hole in the pipe A.

Bend a short piece of i-in. pipe so that the curve will equal the arc made by swinging the suspended motor frame back and forth on the pin. Then secure the pipe to the board by means of a wide flange so it will travel through E. The motor can be held at any point along T by the thumb- screw, according to the pitch of the transom. — L. B. Robbins.

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