Memorandum Surveying the Progress made in rendering ships more immune from danger of destruction by Cordite fire or explosion due to enemy action

1.	During the war the British Navy lost 8 ships due to Magazine explosions. 4 in action, as a result of gun fire i.e., "Queen Mary", "Indefatigable", "Invincible", "Defence". 4 blew and sank in harbour i.e., "Bulwark", "Natal", "Vanguard", "Glatton" (explosion did not sink the ship, which was intentionally sunk later to prevent further explosion due to fire following the first explosion). In 2 others namely "Russell" and "Britannia" explosions in magazines consequent on explosion of mines or torpedoes contributed to the loss of the ships. In 2 lost at Coronel the magazines were probably a contributory cause.
2.	Charges were stowed in metal weakened cases in the magazines, the magazines being open to the handing room in action.
1914.	The precautions existing against flash in those days were roughly :— A "broken" or "indirect" hoist from the guns to the handing rooms, including flash doors in the gunloading hoists and cages. The cordite was carried in a more or less closed cage in all stages during its passage from the handing room to the gunloading position. There were no antiflash arrangements for the secondary armament supply. The normal ships orders in vogue up to Jutland made it sure, by keeping all cages, waiting trays, etc. loaded with cordite, that there was an excellent train of cordite laid from Gunhouse to Magazine.
3.	Jutland. Loss of ships showed that the danger had been gravely underestimated.
1916.	"Queen Mary", "Indefatigable", "Invincible", and "Defence" lost. In "Lion" some time after Q turret had been hit, charges became ignited in the turret; flash penetrated to the shell room, but the magazine doors had previously been closed [Added in pencil: & the mag flooded] and the ship was saved. "Malaya" saved from explosion of 6" magazine and consequent loss by action of individual men only: flash from cordite fire penetrated the shell room to which the magazine was open.
4.	Antiflash arrangements. AFTER JUTLAND.
1916.	Immediate action taken to provide protection against flash danger. (a) Doors of all turret magazines kept closed in action, except when actually passing cordite, pending fitting of flashtight scuttles, trials started in "Excellent" to determine most suitable form of flashtight handing scuttles for Turret Magazines. (b) Handing rooms were built for all Secondary Armament B.L. Magazines, and a series of trials carried out in "Excellent" to determine the best type of scuttle for these handing rooms. No handing rooms were considered necessary or were fitted to Q.F. magazines, where the cartridges, being in brass cylinders were considered safe from flash. (c) Leather aprons fitted between fixed and revolving trunks of turrets. (d) Tops of ammunition hoists in older turrets covered in and trunks of all turrets examined and made as flashtight as possible. (e) Open batteries, fireproof fearnought screens fitted between gun positions. (f) Ammunition passages, fireproof fearnought screens fitted to isolate the different compartments. (g) Special procedure laid down for supply of cartridges both to turrets and secondary armaments to obviate as far as possible having a continuous train of charges from gun to magazines. (h) Splinter proof boxes provided at gun positions for protection of the cordite cases containing ready use cartridges. (i) Clarksons cases were re-introduced for use with hand-worked B.L. Guns.
1917.	The above precautionary measures having been carried out without ship trial it was decided to carry out trials to ascertain whether the arrangements that had been fitted were satisfactory and what further action if any, was required. "Vengeance" was selected for the trials and these shewed that the whole of the measures already taken were successful. Summary of conclusions reached (as recorded in 1917). (a) It is desirable to provide a passage for vent from any compartment to which it is of particular importance that the bulkheads should not be damaged. (b) The antiflash fittings introduced since the battle of Jutland, and modified as a result of these trials, are satisfactory. (c) The general effect of a cordite explosion is in an upward direction, and it should therefore be fairly easy to make the lower turret compartments flashtight. It was also found that:— (a) Magazine doors are not necessarily flashtight even when tightly closed. (b) Ventilating trunks are liable to conduct flash to a magazine. (c) Ignition of the contents of a cordite case in a magazine need not necessarily cause the magazine to blow up, this refers to weakened cases and spontaneous ignition of cordite, which subjects are not dealt hereon.
1918.	Early in the year further trials in the "Vengeance", exploding 2 and 3 15" [Added in pencil: Full] charges in the handing room showed that the new small stiffened access doors to magazines were flashtight only when protected with a screen door of light plate in front: the doors were however too stiff to form efficient vent to magazine. The question of doing away with access doors to Magazine from Handing room was then considered. There were objections to this from a constructional point of view, and therefore further efforts were made to provide an efficient door, trials being carried out in "Prince of Wales" in 1919.
1919.	The new circular door with locking ring proved successful, both in antiflash qualities and as a vent. In this year venting plates and explosion trunks were abandoned as being non flash tight. Trials carried out in "Prince of Wales" of the venting properties of the magazine hatches fitted to secondary armament and Light Cruiser magazines showed that these were unsatisfactory.
1920.	Further trials were carried out to render the circular access door water tight, and to provide an efficient locking arrangement. It was decided that this type was only to be adopted for new Capital Ships. Note. The access doors actually fitted in "Nelson" and "Rodney" are 18" square doors and provided with light plate covering doors. No venting plates are fitted to the 16" magazines in "Nelson" and "Rodney".
1922.	It was decided to fit antiflash scuttles and handing rooms to Q.F. Magazines in new construction, where the magazine was like to be open in action. A new design of antiflash scuttle was being produced, a vertical double compartment revolving type, resulting in economy of space. Pusher hoists introduced - these are much more flashtight than dredgers or whips and have flashtight scuttles at bottom, free venting at top and venting plates on the side of the trunks. Endless chain cordite hoists (6") "Nelson" and "Rodney" have flashtight "heads" carrying the charges in Clarkson's cases. Venting valves are fitted in the "heads" venting upwards, these are the automatically closed when the heads are on their downward journey. Flash proof scuttles are fitted at the bottom and venting plates fitted in the sides.
1923.	A Trial carried out in "Excellent" of igniting one of the lower of 5 4" Fixed Q.F. rounds in a pusher hoist failed to ignite any of the remaining rounds.
1924. 1926.	A Trial carried out in "Excellent" of igniting one of the charges in an endless chain cordite hoist gave fairly satisfactory results. In consequence of this trial venting plates have been fitted to the sides of these trunks as an additional precaution.
5. 1915.	Protection of Bare Charges. (a) The following extract from a translation made in I.D. [Intelligence Division] early in 1915, of a German Ammunition Handbook is quoted as being of interest in connection with this subject. After describing the main cartridge for the 11" gun the book goes on:— "The 11" fore-cartridge. "The large "action" charge of the 11" Q.F. guns consists of main cartridge and fore cartridge........ "To obtain a convenient diameter, these 24 kgs "(the weight of the fore cartridge)" are tied together in half tube lengths in a special cartridge without igniter, over which a cartridge bag is drawn, and to guard against premature ignition the whole is encased in a fore cartridge case of thin sheet brass. "The lid of the fore cartridge is strong and of the same shape as the cartridge case lid, consequently when loading the fore cartridge can slip over the extractor: it is held fast by a silk band. The base of the fore cartridge case is .1 m.m. (.004") thick like the lid of the main cartridge." A similar description of the fore charge for the 8.3" gun states "......The base of the fore charge case is only .1 m.m. thick, like the plate of the charge case lid, so that the flame is as far as possible freely transmitted to the fore charge." No importance was apparently attached to this information at the time as the danger from flash was not then realised. [Marginal note in pencil: Who says so?]
1916.	(b) After Jutland it was realised that the igniter was the danger point: and trials were carried out "Excellent" to ascertain the freedom or otherwise of charges with and without igniters from being ignited due to flash from other charges, molten lead dropping on them, or hot splinters from shell hitting them. The suggestion was also made that the igniter might be supplied separately, and be attached to the charge immediately before loading.

Primary Sources

• The National Archives. ADM 116/2348.