SAFETY OF SHIPS

Evening Star, Issue 23127, 29 November 1938, Page 11

SAFETY OF SHIPS

ON THE HIGH SEAS Once a liner leaves the shipbuilders’ yard and is commissioned and put into service, the work of the naval architect has—to all intents and purposes—been completed. He will be interested in noting bow the vessel fulfils her desired functions, in checking by how small or great a margin she exceeds the estimates of performance on which her design was based, in observing the effect of external commercial factors upon her revenue-earning capacity, and in gathering data for future reference in later designs; but until such time as stress of competition, change of habit, or taste on the part of the most important classes of passengers, new developments in machinery, or some other equally disturbing commercial or technical factor arises to necessitate largescale alterations, the man most deeply involved in the successful creation and production of the vessel will retire back-stage, leaving the handling, running. and maintenance of the vessel herself in the hands of the operating staff.

One of the .most important aids to navigation that has_ been developed during recent years is wireless direction finding, and apparatus is installed in. the Queen Mary enabling the navi-, gation officers to sweep the horizon and locate the direction from which wireless signals reach the vessel—either from shore' stations when the vessel is approaching land, or from ship in the vicinitv. When the range of _ visibility t is small, the wireless direction finder is of great assistance in both events; in the one case it is possible to bring the vessel safely and on a_ straight_ course to within limits in which effective use can. be made of sounding machines, and in the other case to pick up and keep track of the course of another shin on a converging or opposite courseunder fog conditions, when otherwise no certain knowledge would be available as to the direction from which the other vessel was approaching, even though her whistle could he heard. Two ingenious electrical instruments installed in the Queen Mary enable soundings to he taken very rapidly, and these soundings are recorded automatically. Both instruments work on the principle of sending wave impulses to the bottom of the ocean and noting how long the reflections of these impulses take to return to the ship. Another piece of sound-detecting apparatus is fitted in the silent cabinet, which locates the direction from which the impulses resulting from the ringing of an underwater bell are approaching the ship. With this latter apparatus is supplied a table giving the positions of light vessels fitted with such hells and particulars of the characteristics of the iimpulses, sent out in each particular case - , . . , , A timing device is placed over the instrument,’ and this permits of an estimate being made of the distance the sound has travelled —based oiy the time elapsing between the reception ot each sequence of impulses—thereby enabling the ship’s actual position to be plotted on the chart. LOOK-OUT STATIONS.

Wireless direction finding apparatus, electrical sounding machines, and submarine sound detecting apparatus are all extremely useful aids to navigation even m clear weather. When making a landfall in fog,' the service they render is invaluable. For navigating in the neighbourhood of other vessels, however, there is nothing to equal the eyes of the men on the bridge. Normally the master has at least six men on duty on the bridge —a senior and a junior officer, two quartermasters and two boys, in addition to the men at the usual look-out stations. . For their convenience and to assist the naked eye, two large discs of glass rotating at very high speed are provided in the bridge front—known as “ clear view ” screens—while two of the windows are also fitted with hinged anti-glare screens. It is easy to appreciate the importance of these various details when it is remembered that the Queen Mary, steaming at speed, covers nearly 36 land miles every hour.

imagine her approaching another vessel on an opposite and slightly intersecting course, and assume that the other vessel is steaming at only twothirds of the speed of the Queen Mary. It is obvious that these two vessels will be nearing one another at a speed of nearly 60 miles an hour—impressive figures in relation to movements on land, much more so when it is remembered that the Queen Mary weighs over 80,000 tons.

To ensure that the muster shall have full and instant control of the vessel at all times the usual engine-room tele-

graphs are duplicated in the Queen Mary. Special telegraphs of somewhat similar type are fitted on the wings of the bridge for controlling operations on the forecastle when anchoring, and others for maintaining cont rol_ at both ends of the ship when she is being docked.

Instant steps can bo taken to render assistance to persons who have fallen overboard; two lifeboats immediately abaft the bridge and under the direct charge of the bridge officers are kept immediately ready for taking the water. Should collision appear imminent at any time, the master, from the bridge, can instantly close every watertight door in the ship by bringing powerful hydraulic gear into action through the operation of a single valve. By the time that the power reaches the operating cylinder local alarm bells will be operating automatically, warning men in the vicinity that the doors are closed while there is no fear of men being trapped below, since egress can be made from every underwater compartment after the doors have been closed. CHECKING OF STABILITY. It should also be remarked that the master is entirely responsible for maintaining a constant.check on the stability of the vessel. This is worked out frequently, an essential precaution in the case of such a vessel as the Queen Mary, consuming huge quantities of oil and requiring the transfer of fluid weight from one section to another of the double-bottom tanks. At all times, further, the master has undbr his control a highly-trained fire brigade, having their base of operation in a strategically disposed fire station, equipped with comprehensive and reliable fire detecting and extinguishing apparatus covering every single compartment in the ship, together with means for equipping fire-fighting squads for instant action. An alarm of lire reaching the fire station from the automatic detectors would he communicated straightway to the bridge through a special loud-speak-ing telephone. Having at his command on the bridge switches for controlling all fans and electric radiators in every section of the vessel, means for closing all water-tight doors, and means for sending alarms and instructions to the engineers, crew, stewards, and. if necessary, to the passenger accommodation spaces the master would be able at once to take immediate and complete control of the situation. .