Facts About Warships

Grey River Argus, 12 August 1925, Page 5

Facts About Warships

There are some peculiarities about th o American warships. The lattice masts of the battleships which are vis.ting Wellington and Auckland fui example, are peculiar to America, for though the American naval authorities will have no other, those masts have never been adopted elsewhere. It is claimed for this form of construction that it is light as compared with the tripod mast, which the British naval authorities have adopted for all the newer warships. It is also claimed that lattice construction makes it relatively difficult to destroy the masts viith gun fire, as a mast might be struck repeatedlv without collapsing. Still tripods have stood after two of the "legs’’ have been shot away. The objection that Briti’h na.val men have to. the lattice mast is lhe excessive vibration when th- ship is steaming under full power This affects the range-finding instruments, and makes it difficult to take absolutely accurate observations from the spotting stations, which in its turn of course affects the nccuraev of gun fire. I’OWER. AND SPEED.

Though Britain retains on the , number of powerfully armoured lightly armoured and very speedy battle-cruisers, such as the Hood, Repulse, and Renown, the Americans have abandoned this ;ypc altogether Nor will Britain build any more. The extremely powerful and fast American cruisers, which were being constructed have, under the provisions of the Treaty of Versailles, all been scrapped with th- exception of the Lexington and Saratoga, which are being converted into aircraft carriers, armed with 8-inch 50-cahbre guns. These are very powerful weapons, in spite ol their comparitively small bore, sc thrt, either for defence or offence, the Saratoga and Lexington should be able to give a very good account of themselves. As their propelling machinery develops 180,000 hors?-poup-r, or 40,030 horse-power more than that of the Hood, they will be extremely speedy. If deirtroyers he excepted, they will be indeed, the fastest as well as the most, powerful vessels afloat. It is expected that they will be completed in July, 1926. In appearance all classes of American warships differ onsid.wnbly f rom tin? British. A certain lightness ot outline, perhaps, is what distingu.slies them chiefly. By wav of illustrating this point- one might compare the American and British ships to the typical figures of “Uncle Sam” and "John Bull.” The short funnels, nntqual in size- and of very large diameter, which have been th- fashion in the British Novy for several yews, finds no qounlerpart in the Amerioap Navy, 'Jhe American de-ST’nl’'-i S! d ftmnt!?.

less in diameter, and much higher than the British. THE ELECTRIC DRIVE. In their newer ships the Americans have adopted electric drive, a form of indirect drive. Steam turbines are not economical,’ unless they revolve at high speed. On the other hand propellers, tu be efficient, should not revolve at more than 170 revolutions a minute. Indirect drive-—whether electrical, mechanical, or liydraulc—makes it possible to combine a high turbine, speed with relatively low propeller speed. In electric drive the turbines are coupled directly to- electric genera tors, which supply current to electric motors coupled directly to the propeller shafts. In recently built Ameri can battleships there are two generators which supply current m tour motors, one motor he.ng. coupled to each of the four propeller shafts. In cruising on© generator only would be used, and one, two, or three of the four miitors might be ’•cut out according to the speed that it is desired to attain.

A* to the advantage claimed foi electric drive in the “lay out’’ of the machinery in th? engine room the de signer has a far greater amount o( in vt-uide- (.ban would have with mechanical drive. If the propcllei shafts are driven by median.cal gearing from the turbine shafts it is no cessary that the two sets of shattiri.t -hall b- close togitlnr and parade., but in the case of electric drive the generators and turbines may be placed wherever it is most convenient That the propeller shafts can be mau. quite short, as it is possible to place the electric motors which drive them right, aft—how far aft depending cm the width of the hull. The Im-lucre thus afforded in the disposal of several elements of the propelling machinery makes it possibly to avoid undue concentration or weight. All these are important advantages but they are not unattended by grave disadvantages Chief of these is the increased weight In the New Mexico, for example, the weight of the propelling mach nery is 1751 b for every shaft horse power developed, in the Hood, Repulse, Renown, and other modern British war ships equipped with mechanical drive, the weight of the machinery a shaft horse-power would be less than hal: that amount. Shaft or net horse-power is the actual horse-power that ravailable for driving the ship through the w iter. It does not include that power which is lost through engine rcs'stance, friction and so forth. Triple turrets—turrets in whir, three guns are mounted —have Lorn the first been favoured by Arnot mr naval designers. Triple turrets certainly effect a large saving in weight Against this there is a “crowding'’ of

machinery in the turret, which mean, increased difficulty in serving the guns. The British Admiralty na: hitherto favoured twin or i.v.-gun turrets, but in the case of the battle ships Blenheim and Rodney, now under construction, the nite 16-inc!i guns al’e mounted in three triple turrets. In passing a unique feature, in tire disposition of the armaments of these ships may be noted. The line guns are all mounted at the bow end. In the event of a retreat, therefore, the Blenheim and the Rodney could only bring their secondary batteries to bear on their pursuers. The concentrating of the whole cf the primary armament forward is a feature that has met witn cons-derablj criticism, but, of course, the Admiralty technical advisers haive not made such a radical departure without good reason,