German Hand Grenades of the Great War Part Three – The M1915 Diskushandgranate

What’s in the box? 

Ta da!  It’s been a while since we last took a detailed look at, let’s not beat around the bush, devices designed to do horrible things to human beings, so let’s consider the case of German Diskus grenades – the British, surprise, surprise, called them ‘turtle’ grenades.  And the first thing you can see from the shots above & below is that there were two different sized versions, one intended to be used defensively, and one offensively.

Designed in around 1913, the smaller, defensive version was a fragmentation grenade, the picture here on the left showing the sections on the inside of the casing that were designed to shatter on detonation, while the larger, offensive version was a concussion grenade, designed to kill through blast, and thus had no requirement for fragmentation sections, hence the smooth inside of the casing on the example on the right.

German infantryman, second from left, displaying a defensive Diskus grenade (and likely more in the pouch attached to his belt),…

…and here an officer, I presume, demonstrating how to use a defensive Diskus from a trench, by the looks of it early in the war.

German officers with offensive Diskus grenades on display (far left & far right),…

…and two pioneers, the man on the right holding an offensive Diskus, the man on the left a Kugelhandgranate.

A disassembled defensive Diskus grenade, the parts shown, from the left, including the inner aluminium tubing, two powder bags, various inner components, the outside & inside of the shell, and note, in particular, a small star-shaped device without which,…

…well, I imagine these diagrams – defensive version above, offensive below, the operation of both the same – explain everything quite satisfactorily, so no need for any additional clarification from me.  No?

All in due course.  Apart from the obvious variation in size, there were other major differences between the two grenades, not least the fact that the body of the defensive grenade was made from cast iron, whereas that of the offensive grenade was made of thin steel, and thus the basic construction of each differed significantly.  The two shells of the defensive grenade were riveted together using the holes you can see around the rim of the grenade in the first diagram,…

…whereas the two sections of the steel offensive grenade were crimped together, as in this nice example from my collection (above & below).

So how did it work?  Highlighted in the shot above are, from left, spring cap (red), brass tube with notch (pink), four brass inertia blocks (green), and a small star (yellow).  We shall be referring back to this picture as we go along.

Here we have the aluminium tubular assembly, on the left, and in situ in the cutaway on the right.  Four of these six aluminium tubes (in the above photos, the two at the top, and the two at the bottom) enclosed solid slidable brass inertia blocks (highlighted in green on the b&w photo) with a small percussion cap at their inner end and a screw cap at the tube’s outer end.  The horizontal tube contained a detonator on the right, and a longer brass tube (referred to as a ‘safety bar’ in the previous diagrams, and a ‘safety pellet’ in the forthcoming one), fixed with a safety pin, on the left.  This longer brass tube (highlighted in pink on the b&w photo) had a notch at the inner end which enclosed a small star-shaped device in the centre of the grenade (highlighted in yellow on the b&w photo – see also front & side elevations in both previous diagrams), whose four percussion pins pointed towards the percussion caps at the ends of the four brass inertia blocks.  The two powder bags (one in place above) were placed on either side of this tubular contraption,…

…hence the shape of the grenade, as seen here on my example, shown with detonator cap in position (top) and unscrewed (bottom), with two of the crucial screw caps on either side.

Crucial because the grenade was designed to be, in effect, bowled, not thrown like a discus (despite its name), and it was imperative that one of these screw caps at the outside end of the brass tubes made contact with the ground on landing.  A typical internet search will reveal the following sentence on more than one occasion, ‘they were intended to be used like skimming stones across water from trenches and bomb craters in No Man’s Land, or thrown like a discus’.  Well, no they weren’t, because then they wouldn’t have worked, because the screw caps wouldn’t have impacted the ground.  Before all that, however, according to the above British diagram, the thrower would remove the safety pin which would ‘allow safety pellet to be pulled out’.

Maybe.  Maybe not.

So, here’s the safety pin and the spring cap (highlighted in red on the b&w photo), and it ain’t no good removing one without removing the other, because not a lot is likely to occur unless you do (my guess is that the spring cap would be removed prior to any likely action, leaving just the safety pin to remove later).  Once both are removed you can throw your grenade, and once thrown, the next part of the operation relied on good ol’ centrifugal force.  Hurling the grenade in a spinning motion would force the four small solid brass inertia blocks in four of the tubes to slide outwards towards the screw caps, and, likewise the ‘safety pellet’, which would fly out of the now-open hole (and therefore you would not need to remove it yourself, as the diagram suggests – can you seriously imagine removing the safety pin and then fiddling around to get the safety pellet out in the pouring rain, with frozen fingers, knee-deep in mud in a Flanders trench) where the safety pin and spring cap once were, exposing the star-shaped device in the centre of the grenade.  It was then about the landing, and provided the grenade landed on one of the screw caps, the inertia block within that particular tube (or maybe the one opposite – physics is hardly my strong point) would shoot forward, towards the centre of the grenade, where the percussion cap would strike the associated spike in the centre, the spark produced firing the detonator, which in turn would explode the powder bags.  Simple really.

And talking of powder bags, how amazing that such things still exist.  These are mine, and include, not mentioned earlier, a smaller piece of cloth, which covered the central star; you can see it in place in the earlier cutaway image.

This is the second offensive Diskus grenade I own, more of a relic than the previous one, but with one point of particular interest.  The inset shows an example of a practice defensive grenade, painted red, as most, or all, German practice grenades, of all types, were,…

… and I show you because there are vestiges of red paint remaining beneath a later coating of grey on the less degraded side of my example.  This was also once a practice grenade, before being converted into the real thing.

The Germans invented all sorts of contraptions to hurl grenades further, and the Diskus grenade was no different.  Whether this particular apparatus was a success is not recorded.

Before we finish, here’s our pioneer from last post, on the left, and the answer to the question I posed about the contents of his belt pouches becomes clear because you can now just about see the shape of a Diskus grenade in each pouch.  The man on the right wears a canvas bag around his shoulders within which you can trace the outline of another Diskus grenade, and the fair-sized pouch on his belt (on the left of the photo) probably contains more.

Ingenious though Diskus grenades may have been, it appears that, and I cannot imagine this will surprise you, they regularly failed to explode, presumably because they often failed to land on one of the screw caps, or landed in something soggy, but also because they suffered from problems with changes in humidity, a consequence, I suspect, of the basic construction of both versions of the grenade, which hardly proved satisfactory in keeping out moisture over a period of time.

And so, before long, the Diskushandgranate would be superseded by the Stielhandgranate, which would prove to be a far more successful, and long-lasting, weapon of warfare, reaching, I suppose, iconic status in the hands of Hitler’s stormtroopers during the Second World War.