54 



Popular Science Monthly 



Hoisting the concrete boat which weighs more than 

 a ton. It is giving as good service as a wooden boat 



presented it to the U, S. Naval 

 Reserve Force Auxiliary, at 

 Chicago, which is a part of the 

 Great Lakes Naval Training 

 Station. The boat has aroused 

 great interest, principally be- 

 cause it is the work of a man 

 with practically no knowledge 

 of shipbuilding and with very 

 little knowledge of concrete. 



The boat is eighteen feet, six 

 inches long, with a beam of four 

 feet, six inches. It is propelled 

 by a six-horsepower engine and 

 despite the fact that the hull 

 was not smoothed off it is cap- 

 able of making a speed of ten 

 miles an hour. Concrete, con- 

 sisting of one part Portland 

 cement to one and a half parts 

 of sand, was applied with a 

 trowel on a carefully designed 

 framework of steel ribs, and was 

 allowed to harden under cover. 

 The boat weighs two thousand, 

 three hundred pounds, twice as 

 much as a wooden boat. 



The Great Lakes Training Station 

 Gets Its First Concrete Boat 



FOR many years concrete has been 

 successfully used for barges and 

 pontoons, but it is only recently that it 

 has been used for other types of vessels. 

 Norway has completed a concrete boat 

 of three thousand tons, and a much 

 larger boat is now 

 being constructed 

 in San Francisco. 

 Montreal and 

 Seattle are centers 

 of concrete ship- 

 building and New 

 England ship- 

 builders are 

 watching the ex- 

 periment with in- 

 terest. 



The accom- 

 panying illustr;-.- 

 tion shows a con- 

 crete boat built by 

 Walter N. Dow- 

 sey, a lumberjack 

 of Iron River, 

 Michigan. He 



The axle periscope 

 inspector to examine 

 comotivc axle and to 



Looking Through a Steel Axle with 

 a Periscope 



THE periscope, so efficient in trench 

 and submarine warfare, now has 

 a pacific application. It promises to 

 avert many accidents resulting from 

 defective locomotive axles. 



The axle is bored longitudinally, the 

 size of the bore 

 being ample to per- 

 mit insertion of the 

 periscope, which is 

 about forty inches 

 long and one and 

 one-half inches in 

 diameter. At one 

 end is a magnifying 

 mirror upon which 

 a light is thrown 

 from the handle. 

 Looking through 

 the periscope, in- 

 spectors obtai/i a 

 clear view of every 

 part of the axle 



^, , ., . and are enabled to 



enables the railroad ^ • ^ j.\ a 



every part of the lo- detect the flaWS m 



locate flaws instantly the steel. 



