Part 14 (1/2)

Thus we see ill.u.s.trated what has just been said, less guns and thinner armour, to allow for more engine power and higher speed. Or, to put it the other way, we observe how higher speed was attained at the expense of the guns and the armour.

But just as the _Dreadnought_ was followed by other still greater improvements in the same direction we get, in 1910, the famous s.h.i.+p _Lion_, a vessel not unknown to the Germans, a ”super-Invincible.”

This s.h.i.+p has a tonnage of over 26,000 and 70,000 horse-power. It was designed to do 28 knots.

We saw the use of these s.h.i.+ps in the Jutland battle, when, using their high speed, they attacked the German battles.h.i.+ps and kept them engaged while the slower battles.h.i.+ps came up. Though they suffered severe losses, which probably the more heavily armoured battles.h.i.+ps would have escaped, they held the Germans so that it was only the failing light which saved them from utter destruction.

Another example was the way in which they hunted down Von Spee and his squadron off the Falklands, when they caught the Germans because of their higher speed and then sank them by means of their heavier guns with practically no loss to themselves.

We saw them again in the Heligoland battle, coming up to the a.s.sistance of the lighter vessels just in the nick of time and scattering the enemy like so much chaff.

A fact little known to most people and productive of much surprise is that these battles.h.i.+ps and cruisers are not such very large vessels, when compared with those of the merchant service. The _Lion_ is 660 feet long and 86 feet wide, the _Aquitania_ is 930 feet long and 98 feet wide, and the _Olympic_ is 882 feet long and 92 feet wide.

The mighty _Orion_ makes a poorer showing still in point of size, since she is only 545 feet long and 88 feet wide--little over half the length of the _Aquitania_.

It is difficult to compare the tonnage of a wars.h.i.+p with that of a merchant s.h.i.+p, since they are not measured in the same way. The former is the ”displacement” or actual weight of water displaced: in other words the precise weight of the vessel in tons of 2240 lbs.

The tonnage of a merchant s.h.i.+p, however, has nothing to do with weight but is based upon capacity and is arrived at by a purely arbitrary rule, thus: all the enclosed s.p.a.ce in the s.h.i.+p is measured in cubic feet and the total is divided by one hundred. That gives the gross tonnage. To arrive at the net tonnage the s.p.a.ce occupied by the engines and all other s.p.a.ce necessary for the working of the s.h.i.+p is excluded.

Originally the tonnage of a merchant s.h.i.+p was the number of ”tuns” of wine which it could carry.

Thus, you see, comparing the tonnage of a wars.h.i.+p with that of a merchant s.h.i.+p is somewhat like comparing a pound with a bushel. Net registered tonnage is generally considerably less than the displacement tonnage of the same s.h.i.+p, so that a wars.h.i.+p is usually less than a merchant s.h.i.+p of the same nominal number of tons.

And now let us turn to some of the internal arrangements of these wonderful s.h.i.+ps, more particularly to the means for working the guns.

Each turret is placed over the top of what we might call a well, running right down deep into the inside of the s.h.i.+p. At the bottom of this well is the magazine, where the sh.e.l.ls are stored and also the cartridges containing the explosive which drives the sh.e.l.l from the gun.

Underneath the turret, forming a kind of bas.e.m.e.nt to it, is a chamber called the working chamber, and up to it the sh.e.l.ls and cartridges pa.s.s by means of lifts. For safety's sake only a small quant.i.ty of explosives is kept here at any one time, but it is from here that the guns overhead are fed. Sh.e.l.ls and cartridges alike pa.s.s up as required by means of hoists right to the guns. Indeed, the hoists are ingeniously contrived so that in whatever position a gun may be the hoist stops exactly opposite the breech, or opening at the back of the gun through which it is loaded. Then a mechanical rammer drives the sh.e.l.l or cartridge into its place in the gun.

The hoists are worked by hydraulic power or electricity, and in most cases by both, arrangements being made so that either can be used at will, thus serving as alternatives in case either should get out of order.

The turrets themselves are also turned by power. Indeed, so heavy are the weights involved that only by the use of carefully designed machinery is the operation of such great weapons made possible. A single sh.e.l.l of the 135-inch gun weighs 1250 lbs.

Around each turret there is placed a wall of thick armour plate as high as it is possible to make it without interfering with the movement of the guns. This is called the barbette armour and the s.p.a.ce enclosed by it, in which the turret stands, is called a barbette, an old fortification term meaning a place behind a rampart.

The turret is covered over, as has already been remarked, by a steel hood, so that altogether the guns and their crews are about as well protected as it is possible to be.

That all this means a considerable burden upon the s.h.i.+p is shown by the fact that a pair of 12-inch guns with their turret and barbette armour will weigh something like 600 tons, and if there be five of them that means 3000 tons in all.

Down below in the magazine there are lifting appliances whereby the sh.e.l.ls can be readily picked up and run to the hoist. Moreover, there is elaborate machinery for keeping them cool. Our allies the French had, years ago, several bad accidents through the explosives going off spontaneously in their s.h.i.+ps, and this is quite likely to happen if the magazines become too hot. So refrigerating apparatus is installed similar to that employed in meat-carrying s.h.i.+ps, which provides a constant flow of cool air into the magazines.

The s.h.i.+ps also are subdivided to the greatest possible extent consistent with efficient working, so that in the event of a collision or a torpedo making a hole below water the s.h.i.+p may not sink. As far as possible the divisions or bulkheads are made to run right from top to bottom without any openings, but that obviously is a very inconvenient arrangement, so in many places there have to be doorways through them, leading from one part of the s.h.i.+p to another. In such cases these are closed by water-tight doors, which can be shut before the s.h.i.+p goes into action or into any dangerous region.

The engines of these vessels are now always turbines. This type of engine has many advantages over the older type, in which certain parts move to and fro, that motion being changed by cranks into a round and round action. For one thing, they are lighter for a given power, so that more power can be put into a s.h.i.+p without adding to the weight. That means higher speed. Then there is less to get out of order. Anyone who has been into a s.h.i.+p's engine room where to and fro or reciprocating engines are at work will realize this, for there is a maze of rods and cranks all moving together, and many parts which need to be oiled while in motion and which would get hot and tight if they were not carefully looked after. All this in an enclosed s.p.a.ce with possibly an uncomfortable motion of the whole s.h.i.+p used to make the engineer's life at sea a very hazardous and unhappy one.

But the turbine is entirely enclosed. There is nothing to be seen moving at all. Indeed, there is only one moving part, and that is coupled directly to the propeller-shaft, so that nothing could possibly be simpler.

CHAPTER XVII

HOW A WARs.h.i.+P IS BUILT