POURED INTO A MOULD.

Manawatu Herald, Volume XXXIX, Issue 1737, 12 July 1917, Page 4

POURED INTO A MOULD.

BUILDING CONCRETE SHIPS. SAMPLES FROM NORWAY. Though the- eonsiruclion of concrete ships may scorn strange, it is a problem that has already been overcome in other parts of the world. Shipbuilders in Norway recently turned out a reinforced concrete vessel of over (!,0()() tons, and it is claimed to be a success. If such ships can be produced in Norway, there is no reason why Australian engineers cannot make a success of fhe same class of work, says the Sydney Sun. A few years ago the Sydney Harbour Trust took up the idea of building concrete pontoons, and when the new jetties at Circular Quay were being built several of the old wooden berths were replaced by concrete. The one in use at .Milton's Point jetty is the biggest , of its kind in Australia. It was constructed at the Glebe, and though doubt was expressed as to whether it would lloat, the launching was a complete success. The new pontoon was towed into position at the Quay, and has not since given the slightest trouble. It floats just the same as the wooden ones, and doubtless many travellers* are unaware that it is built of concrete. HOW THEY ARE BUILT. The method of constructing ships or pontoons of concrete is just the same as that applied to a reinforced concrete building. All modern steel structural buildings the merely battleships upended. In the building

of these ships it is necessary to lay down the frame very much in the same way 7 as is the case with the present ships. Moulds are made of wood and constructed to the design of the ship which is to be built. These moulds are laid down fn sections round the frame of the structure and bolted together. Inside these there will again be placed the reinforcing material, such as steel bars or wire extensions. The concrete is mixed in the usual iway, sand, grit, or gravel being used. .It is then put into the moulds and tramped down. After the lapse of a few days, when the cement is dry, the moulds are removed, and the next section proceeded with. The reinforcing material is carried on in such a way that there is no possibility of preventing it binding into solid mass almost as hard as steel itself. The impervious' nature of litis material and its absolute strength are proved by the qualities of the (loors in modern buildings, which are made of the same material. It is fireproof, and of greater resisting strength than any other materials. ONE MOULD, MANY VESSELS. With the concrete ship, it :s the case of one mould, many ships. The vessels are built in sections, each having its own mould, so that many vessels of any particular design can be constructed once a complete set of moulds is made. As each part lias set, the mould can be removed and shifted to any spot, and .again filled with concrete, which in turn would be emptied, and become part of a great line of ships, all of which would be ready for launching within a few weeks of each other. No area of water-front would lo too big or too small for the construction of this class of ship. The materials for the making of cement abound throughout the whole of: Australia, and there should bo no great difficulty in providing the steel reinforcement required for this work, it not hong of (lie nature of high-grade steels.