that when the fire-engines are working the pressure from the fire

main is prevented

from affecting the

how the valves at the ship's side are geared to be worked from the level of the pump, and also from the main deck if desired.

To pump any compartment out, all the valves between the fire-engine or Downton and the compartment must be opened. Thus for a forward compartment all the bulkhead stop valves

COTTER WITH

PADLOCK

must be opened between the pump and the compartment, besides the valve on the particular branch.

A book is issued to each ship, and, among other things, it is stated how each compartment may be drained or pumped, and where the valves are worked from. A specimen page is given at the end of this chapter. Take, for instance, the forward boiler-room. It can be drained into the engine-room through the main drain; the 13-in. S.V. is worked near the valve, and also at the main deck, the deck-plate being between stations 71 and 73 on the port side. The boiler-room can also be pumped out through the branch from the main suction. The 4-in. S.D.N.R.V. on this branch is opened from a deck-plate on the middle deck between stations 71 and 73.

In "protected" cruisers suctions are taken down to the bottoms of the upper bunkers to clear water away. These ships would get water above the protective deck if the thin side were riddled.

In working a valve it should be noted that the valve is not necessarily closed when the indicator points "shut," as after some wear of the gearing it is necessary to work beyond this point to get the valve well down on its seat.

Flooding. In order to permit flooding of the compartments of the double bottoms, the valve 2 in Fig. 95, and the valve to the particular compartment, both of which under ordinary circumstances of pumping act as non-return valves, can be lifted up off the seats so that flooding can take place. This, however, can only be done deliberately, as the valve cannot be lifted right up unless a locked pin is withdrawn (see Fig. 97). In order,

therefore, to flood a double-bottom compartment we have to open a number of valves (Fig. 95), viz. Kingston (K) valves A and 1, unlock and lift up valve 2, and also unlock and lift up the valve leading to the particular compartment. The book above-mentioned states from which Kingston each compartment is flooded.

The wing compartments are flooded direct from sea valves placed as shown in Fig. 91. It will be noticed that each pair of wings has a flooding valve. The trimming tanks forward and aft can also be flooded direct from the sea.

Special arrangements are made for flooding magazines direct from the sea. Usually one Kingston supplies a number of magazines, etc. Besides the valve at the Kingston a valve is placed at the magazine, both of these being locked valves, which must be deliberately released to allow flooding to take place. They can be worked from the main deck or at the valves as may be desired. For trial purposes the outer, valve would be first opened so that the connecting pipe would be filled. This valve is then closed and the magazine valve opened. The water which then enters can be caught in a bucket. Where a Kingston valve is used only for magazine flooding, it is only necessary to fit one locked valve close to the magazine in addition to the Kingston. Where a Kingston serves other purposes a valve must be fitted at the Kingston, so that it may be open without flooding the magazine floodingpipe (see Fig. 100). No means are provided for draining magazines.

Dry Dock Flood.-Fittings are also provided for flooding magazines when the ship is in dry dock. A pipe is taken, between the Kingston and the magazine (Fig. 100), to the upper deck, and fittings, to take hose connections, are placed on this pipe above the main and upper decks. In the event of fire, hoses could be taken from the dockyard and the magazines flooded. In recent ships the hoses from dockyard are arranged to connect on to the Kingston direct, by means of a fitting which can be secured to the Kingston opening when the ship is in dry dock.

Air Escapes.-When flooding any closed compartment it is necessary to provide an escape for the air. Pipes are led from the crown of the compartment, as in Fig. 93, with plugs on the upper ends. These plugs, when unscrewed slightly, allow the air to escape, and when the compartment is full they can be readily screwed up again. Plugs are also provided on the manhole covers (Fig. 48).

The air escapes from the magazines are constructed with a

simple lift valve, as Fig. 101; the pipe is led well up above the crown of the magazine and bent round, with the end perforated. In ships in which the crown of the magazine is near the waterline, these air escape valves are provided with a spring to

LEATHER

MAGAZINE

NETTING

TOP

GRATING.

cause them to lift easily under the

small pressure.

Fire Main (Figs. 102 and 103).The fire main and its system of pipes is obviously a most important set of fittings in a war-ship. The fire main itself in a large ship is a copper pipe 5 in. diameter, running all fore and aft under the protective deck. It is connected in the engineroom with the fire and bilge pumps, stop valves being fitted to shut off the fore-and-after portions of the system as desired. The fire main system. can be charged from the Downton pumps if required, but the connection is fitted with a non-return valve, so that the pressure in the fire main may not affect the Downton pumps. The fire main is not rigidly connected to the protective deck, but is either supported from bulkheads or from slings connected to the deck. Branches are taken from the fire main to each stokehold, to submerged torpedo-rooms, capstan engine-room, ammunition passages, etc., with connections at each place for attaching a couple of hoses.

FIG. 101.-Air escape to
magazine.

Rising mains are led at intervals to the upper deck, two of these are led up under protection inside the barbettes. Each rising main has a stop valve beneath the protective deck at its junction with the fire main, and these valves are placed in accessible positions so that they can be worked from below the deck if desired. They are also geared to work from above the deck. To most of the rising mains there is also a stop valve beneath the main deck, to shut off the pipe above that deck in the event of the pipe being damaged in action. Branches are taken from the rising mains for flushing w.c.'s, washing out ash-shoots, washing out barbette guns, etc. One-inch bib valves are placed on rising mains between middle and main decks, main and upper decks, and in ammunition passages for drawing off small quantities of water if desired.