RISKS REDUCED.

Auckland Star, Volume LXIII, Issue 219, 15 September 1932, Page 10

RISKS REDUCED.

SAFETY OF SEA TRAVEL.

UFE ON MERCHANT SHIPS.

GYRO COMPASS AND RADIO.

The most important event of 1032 in shipping circles had been the ratification of the International Convention for the Safety of Life at and of the International Load Line Convention by the Government of Great Britain, said Mr. G. E. Breeze, M.l.Mech.E., of Wei lington, in an address in Christchurch this week on the safety of merchant ships at sea. Much experience affecting safety at sea had been accumulated by maritime powers during the Great War, Mr. Breeze said. An International Convention was held in 1929 which set up important, provisions which were agreed upon by all the contracting Governments. This convention was followed by an international load line conference in 1930. ' .

The theory of the load line was that there was a maximum load which a given ship could carry ia safety. If this line was placed too low, there would be a loss of carrying power. If placed too high, the ship would suffer from strain, her speed would be reduced, and there would '•be a risk that she would be lost. In the British Mercantile Marine ships had first been marked with line in 1875. In 1890 sailing ship tonnage was disappearing, and steel was replacing iron, so that revised load line table's had to be drawn up, these being adopted by other maritime countries in 1900. The United States owned a large number of "tankers" —an improved type of ship, Which had developed during the last two decades. It was possible to load these tankers much more deeply than ordinary cargo ships. Safety of Passengers. In regard to ship design, Mr. Breeze said a difficult problem was the determination of the degree to which the hull should be divided into water-tight compartments. An unsinkable ship was impracticable, but water-tight compartments were essential to ensure some prospect of the vessel remaining afloat long enough for assistance to be obtained. Loss of stability and consequent capsizing were caused by the force of wind and sea, flooding below or on deck, shifting of cargo, distribution and loading of cargo and passengers, or the heeling of the ship in turning due to the action of the rudder. Every ship must have a reasonable margin of stability against such contingencies. In passenger vessels with several decks and requiring to carry heavy boats and launching gear, provision »vas made for stability by increasing the beam. However, a large number of factors affecting stability were under the control of the captain. He decided where cargo had to be placed and had to exercise great care in storing cargoes liable to shift. • Passenger ships were surveyed annually and cargo ships at least once every five years. A vessel undergoing complete survey was placed j in dry dock and a surveyor tested all plates and rivets with a hammer. The most frequent defects were corrosion and slack rivets. The main engines and all other, machinery were examined once a year. Every three years it was necessary to withdraw the tail shaft or shafts and inspect them for wear, flaws and corrosion. Fracture of the tail shaft frequently caused serious damage to the hull and perhaps the sinking of the vessel, as was instanced by the loss of the Tahiti in. 1930. Aids to Navigation. There were certain aids to navigation which made life at sea much safer. The gyro compass was becoming popular. This compass was not affected by any magnetic influence, but derived its control from the rotation' of the earth.. It was more accurate than the magnetic compass. The leader cable which enabled ships to make port in foggy weather, the direction finder and the range finder were further aids to safety at sea.

Outbreaks of fire on vessels were caused mainly by spontaneous combustion, Mr. Breeze said. The combating agents were water, steam and gases antagonistic to combustion. The two methods of extinguishing a fire were reducing the temperature below firepoint or cutting off the supply of oxygen. The only satisfactory way of dealing with an oil fire was by the exclusion of oxygen, as water often extended the fire zone by sinking through the oil and providing a surface for floating the blazing fuel. Every passenger ship was required to carry two wireless transmitters, the main one having a range of 1,00 nautical miles and the emergency installation a range of eighty nautical mijes. Wireless communication had thus been one of the greatest means of ensuring safetj' of life at sea. In his concluding remarks the speaker stated that a standard of absolute safety had not been reached, as an unsinkable ship could not be made a commercial success, but that travel by sea was safer than it had ever been, and 110 less safe than travel on, land.