The British Army used several signal grenades from their introduction in the 20th century.
Usage
The grenades were used to communicate information through pre-arranged combinations of coloured smoke and lights. Generally smoke was for daytime use and lights at night but some light producing grenades were suitable for daytime use.[1]
List
Rifle grenades
Used with rifle discharger clipped to front of rifle and propelled by blank cartridge with 30 grains of ballistite.[2] Signal grenades were fired holding the rifle at 70 degrees, the butt on the ground and the rifle trigger uppermost.[3][a]
No. 42 Day Signal - Four different colours of smoke candle. With a parachute.
No. 43 Night - similar to No.42 but with coloured stars. The stars are separated by 12 ft of cord and burn simultaneously
No. 45 Night Signal - similar to 42 and 43 but the star changes colour during use e.g. white-red-white or red-green-red
No. 48 Day or Night Locality Signal - four flash signals which fire sequentially with short delay between each.
No. 52 - as No. 43 but three white illuminating stars
Rodded grenade type where a 15-inch long rod at base of grenade is inserted into the rifle[b] and fired from barrel with a blank cartridge of 43 grains cordite.[2] This was older method of firing grenades.
No. 31 Day Signal - smoke candle and parachute
No. 32 Night Signal - 2-3 coloured illuminating stars and parachute
No. 35 Night Signal - changing light and parachute similar to No. 45
No. 51 Day or Night Signal - white illuminating stars and parachute. same as No. 52
Hand grenades
No. 83 Signal Smoke Grenade - post Second World War[5]
^A gas port on the discharger was used to adjust range between 80 and 200 yd (73 and 183 m) when firing other types of grenades but signal grenades were used with port closed [4]
^The rifle was given reinforcement in the form of wire binding round the fore end of the gun over 5 inches[2]