The champions of wooden ships urged in response that it would be impossible to build an all-steel fleet in season to meet the emergency. Conceding that the steel ship was the better they insisted that the time required for building yards suitable for this form of construction and the delay that would necessarily attend the furnishing of steel by mills already overcrowded by orders for munitions would postpone to the distant future the completion of a fleet which should be ready to take our soldiers to the theater of war and carry over the supplies necessary to maintain them there. Nor did the advocates of wooden ships fail to point out the special advantages possessed by their form of construction in this particular emergency. We were building to beat the submarine. Of all vessels the steel ship suffers most from the explosion of a torpedo beneath her hull. A hole of from five to ten feet long, and equally broad is torn in the thin "skin of the ship," which is not more than three-fourths of an inch thick at most, and the weight of the hull, deprived of interior buoyancy causes it to sink immediately. Many steel vessels of considerable size were totally engulfed in less than two minutes after sustaining a torpedo shock.

.. A wooden bottom, on the contrary, is not so badly shattered by a torpedo explosion, while the natural buoyancy of the hull, unless laden with a particularly heavy cargo, will keep it afloat for some time after being torpedoed. In nearly every instance of the destruction of a wooden craft the submarine was forced to make her work complete by shell fire, or by sending a party aboard to put the torch to the victim. The annals of the sea are full of stories of wooden derelicts that floated for years after being abandoned by their crews as in a sinking condition.

MILES OF SHIPYARDS GROWING WITH INCREDIBLE SPEED UPON A MARSH

Like most hotly contested public questions this controversy was finally ended by a compromise. While the chief tonnage was to be of steel, considerable recognition was given to the builders of wooden ships. At the end of 1917 contracts had been awarded for 353 wooden vessels, and for 58 composite vessels, making a total of tonnage other than steel of 1,460,900. In the eager search

for ways in which the fleet might most rapidly be increased marine architects turned to concrete as a shipbuilding material. To the unprofessional mind a ship of stone seems as ridiculous a conception as seventy-five years ago a ship of iron appeared to the multitude. But even before the war concrete barges had been employed, and the method of construction was reasonably perfected.

It was urged that the steel rods and bars used in reenforcing the concrete construction could be made at the smaller mills and thus avoid interfering with those engaged in producing material for steel ships. Concrete could be made anywhere; was easily handled and molded to any desired form. After careful consideration a standard design for a concrete ship of 3,500 tons was adopted and contracts let. One such ship had been completed at the time of the publication of this book-the "Faith”— 336 feet long with 45-foot beam. She had in the first six months of her service made the long run from Seattle to a Chilean port, thence through the Panama Canal to Chili again. An officer said of her, "She may not be good to look at, but she certainly delivers the goods." Her service afloat has as yet been too brief to justify conclusions as to the merit of concrete as a shipbuilding material. Its opponents argue that a hull of concrete would lack elasticity, and being rigid, would crack and yield under the weight of the cargo in the racking strain of a heavy sea. But its advocates deny this, alleging that a re-enforced concrete ship has all the elasticity of an allsteel ship. In fact, scientific tests have shown that steel and concrete have practically the same co-efficient of elasticity. From the standpoint of economy concrete leads all materials, it being estimated that the material for a 5,000-ton monolithic ship would cost $60,000, while the steel for a freighter of the same size would cost $300,000. Although the experience of the United States with this material has been too brief to be of much value, Norway has built and operated successfully many "ferroconcrete" ships. A curious fact is that the method of construction there compels their launching keel uppermost. They are righted in the water by a system of airtight compartments.