One-Piece Ships of Stone 



Already a company has been formed and financed to 

 design and build concrete ships of 4,500-ton capacity 



By Joseph Brinker 



Broadside view of 550-ton concrete barge used by Arundel Sand and Gravel Company of Baltimore, Md. 

 This picture was taken just before the barge was launched. The barge has been in use for several years 



GONCRETE ships are possibilities. 

 They may be built in addition to 

 steel and wood vessels to offset the 

 acute submarine peril. According to au- 

 thorities, the German' U-boats are sinking 

 Allied and. neutral tonnage much faster 

 than it can be renewed. This cannot go 

 on. If it does, we shall lose the war. Even 

 our Government-controlled shipbuilding 

 program for steel and wooden ships will 

 not produce -sufficient tonnage to offset the 

 present U-boat toll unless this tonnage is 

 greatly increased by the use of some 

 new substance. 



Concrete seems to be this sub- 

 stance. Already a large com- ^.Wood ra 

 pany has been formed and 

 financed in San Francisco 

 to design and build sea-go- 

 ing vessels of 4,500-ton ca- 

 pacity to be made of re- 

 enforced concrete. Plans 

 now drawn up show these 

 vessels to be three-hundred 

 feet long, with a beam of 

 forty-six feet and a draft of 

 twenty-four feet. The con- 

 crete hull is to be six inches 

 thick and the steel re-enforc- 

 ing rods are to be welded 

 together to reduce the quan- 

 tity of steel required to a 

 minimum by avoiding the 

 waste from laps and bolting 

 otherwise necessary. 



It has been calculated 

 that the steel re-enforcing for 

 the vessel will weigh less 

 than the bolts needed in a 



wood ship and that the completed hull will 

 weigh less than that of a wood boat of 

 the same carrying capacity. Allan Mc- 

 Donald, the designer of the ship, estimates 

 that it can be built in ninety days and 

 that turbine engines of two thousand five- 

 hundred horsepower will be sufficient to 

 drive her at a speed of fourteen knots, 

 which is considered enough to enable a 

 boat to escape a submarine under ordinary 

 conditions. 



There is no question about the avail- 

 ability of the concreting materials and that 



The Mid -Ship Section of a Concrete Boat 



It would be made up of light steel framework with wire re-enforcing on the sides. The 

 concrete covering is shot into place by compressed air. The bottom of the vessel is 

 cast in forms in the usual way. Poured concrete has much less density than that shot 

 into place and is liable to be more porous than the kind placed under pressure. A slice 

 is shown cut out of the boat from lower deck to lower deck in order to indicate the 

 position of the steel re-enforcing rods placed longitudinally through the framework 



556 



