So, I am watching a movie on TV, the Britannic, IMDB has a blurb on it here.
A good question might be, “Is anything in this movie real?” but I already know that film-makers take liberties when making a film, even about historic events. To further answer this question, the film is made with some of the poorest computer graphics around.
Early in the film, a german torpedo boat fires two torpedoes at the Britannic. One misses by inches, making a very suspensful moment in the movie. The other one is destroyed by machine-gun fire from a lewis gun. My question is, can torpedoes be destroyed by machine-gun fire?
As a side note, I seem to remember something about this being posted on this board before, but I cannot find it after searching.
Having watched a episode of Mythbusters on the subject of finding shelter from bullets in the water, and a bit of experience shooting water myself (just today shot a .280 through a 2L Coke bottle of water), I would say that unless the torpedo is merely 2-6 inches under the surface, and shot at perpendicularly to the water (which would mean it’d have to be very close to your vessel, and likely do close to as much damage as a direct hit), machine gun fire (particularly from an early 20th century model like the Lewis) would be as effective as throwing stones (a stone, if chucked whilst the torpedo is far enough away, may even detonate the charge prematurely), scrap that, less effective than throwing stones.
I can’t see it happening, unless a very lucky bullet hit the right part of the contact pistol (contact fuse) and triggered it. The main explosive charge is a stable high explosive mixture based on TNT. You need an explosive initiator, like a blasting cap, to set it off.
Having googled up this interesting and informative article I agree with you - torpedoes seem to have been set to run at 10 feet or more underwater, and I can’t imagine a rifle-caliber machine gun being able to do anything at that depth.
Germany also had similar problems with their torpedoes in the early part of the war. Admiral Raeder had the senior officers responsible for the torpedo problems court-martialed. See The Norwegian Operation and the Torpedo Crisis. Many U.S. submariners would have liked to have seen some heads roll at the Navy’s Bureau of Ordnance, after being repeatedly told that the torpedoes were OK, and that they were the problem.
Ok, well I do not think it makes much of a difference, but just to be certain…
The Britannic was sunk November 21, 1916. Hence the torpedo attack would have to had happened just a few days before. Everyone has cited references which date to WWII, around 1937 & 1939. The torpedoes that attacked Britannic would have to be made some time earlier than 1916. Would 1916 torpedoes be vulnerable to machine-gun fire?
Early German torpedoes used TNT or Hexanite (TNT & Hexamine). From some things that I’ve read, TNT requires either a extra-powerful blasting cap or a blasting cap with a booster charge for reliable detonation. TNT was designed to be a “safe” explosive, like most military explosives, immune to fire and projectile impact.
A bullet would have to hit the right part of the contact pistol to detonate the main charge, and it might not have enough energy to do that, depending on the design of the contact pistol and the trajectory and impact point of the bullet. The contact pistol is designed to go off when the torpedo hits a ship, an event that produces far more energy than anything coming out of a machine gun.
I think the key issue here is not whether the torpedo can be detonated, but whether it travels close enough to the surface to even be hit. Certainly, modern torpedos which work by cavitation would not, since they are designed to detonate below the keel of the target and thus would travel quite far under the surface. Wikipedia says most WW2 torpedos also worked on this principle, but there are also pictures of early WW1 battleships with “torpedo nets”, which would indicate that early torpedos still worked on “impact” with the targets hull, and thus may have to travel close enough to the surface to be hit by surface gunfire.
One thing from the mythbusters was that the higher the speed of the shell the less it penertated water (basically it disintergrated). If the machine guns fired slower, heavier rounds the chance of hitting the torpedo should have been higher.
Well I don’t remember that seen, but even though the germans were firing down onto the allied forces in landing crafts, wading ashore, the projectile would still have slowed down to, perhaps to subsonic speeds before hitting the water, so the round would not be as prone to disintergrate on water impact.
The Wikipedia Torpedo article includes a link to this photo of a near miss by a WWI German torpedo. Clearly that torpedo was running on the surface and could have suffered damage from machine gun fire. (The machine gun would not need to blow it up in real life, (just mess up its propulsion, steering, or buoyancy), in order to prevent detonation, although I would guess that a copper-jacketed round fired into the warhead might make it exlplode.
While the source of the photo is given, its provenance is not, so I cannot confirm that this was an actual combat photo of a surface-running torpedo.
I have a very vague memory of reading an article about the idea of using gun turrets on submarines firing supercavitating bullets as a last resort measure against torpedos.
Does that ring a bell on anyone?
I’ve read in real books (not the web) that WWII frogmen were shot at with machine guns at what was probably a similar angle (okay, maybe a shallower angle, but the men weren’t ten feet down, either). The bullets slowed so much at about 4-5 (IIRC) that the men caught them in their bare hands as an amusement.
I recall that movie scene showing machine-gun bullets killing American forces who were perhaps 4-5 feet underwater. I too wondered whether that scene was accurate.
The cannon shells would detonate on hitting the water. The shockwaves from that might do something, but the shells wouldn’t reach a torpedo unless it was running very shallow.
Another thought was having a mechanism like depth charges to fire into the path of a torpedo. But then I do remember a WWII veteran on a documentary mentioning in his account of a torpedo attack that you don’t see anything coming, you just get the thump when it hits the ship.
That makes sense I suppose- to see the cavitation track or wake of a torpedo running 10+ feet underwater you’d probably need it to be daylight, with a pretty flat sea, and to be looking in the right direction. In the North Atlantic that would be pretty unlikely.
