# German WWI trenches designed with perfect 90 degree corners? Did it offer Shrapnel protection? **URL:** \ **Category:** Factual Questions\ **Created:** [October 22, 2012, 9:48pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569 "2012-10-22T21:48:31Z")\ **Posts on this page:** 12\ **Page:** 2
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [October 23, 2012, 4:11pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/21 "2012-10-23T16:11:29Z")
> [@smiling\_bandit](#): > > Actually, I believe General Grant (or more likely one of his staff) developed them for the Siege of Vicksburg. > [@Hypno-Toad](#): > > Engineers used them in the Rennaisance when investing enemy fortresses. That may be, but it’s not like I’m unable to provide [a citation](http://www.google.com/#hl=en&sclient=psy-ab&q=longstreet+trench&oq=longstreet+trench&gs_l=hp.3..0i30l2j0i5i30l2.1211.6396.0.7060.19.18.1.0.0.3.1462.4184.11j4j0j1j6-1j1.18.0.les%3B..0.0...1c.1.aHqM0ISoHcU&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=7a7241402b8d17be&bpcl=35466521&biw=1280&bih=887&safe=on). Longstreet is widely credited with introducing the transverse (or traverse, it’s either two words frequently confused, or it appears to be spelled both ways in various sources) trench to what passed for “modern” warfare in his day. ---
**Author:** ![solosam](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@solosam](https://boards.straightdope.com/u/solosam)\ **Post date:** [October 23, 2012, 4:15pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/22 "2012-10-23T16:15:33Z")
In general, the WWI trenches were quite effective. Check out some battles such as the 1916 Battle of the Somme. The Brits fired 1.73 MILLION rounds over the course of 5 days, (the world’s largest bombardment up that point) and accomplished diddly squat. The German casualties were so light that the British got cut to pieces when they finally launched an infantry attack. By comparison, the Battle of Messines required 3.25 million rounds of heavier and higher quality ammunition to be successful. > **[Welcome - The Long, Long Trail](https://www.longlongtrail.co.uk/)** > > All about the British Army of the First World War. Find how to research the men and women who served, and stacks of detail about the army organisation, battles, and % battlefields. ---
**Author:** ![Hypno-Toad](https://avatars.discourse-cdn.com/v4/letter/h/b2d939/32.png) [@Hypno-Toad](https://boards.straightdope.com/u/Hypno-Toad)\ **Post date:** [October 23, 2012, 4:57pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/23 "2012-10-23T16:57:08Z")
> [@Sailboat](#): > > That may be, but it’s not like I’m unable to provide [a citation](http://www.google.com/#hl=en&sclient=psy-ab&q=longstreet+trench&oq=longstreet+trench&gs_l=hp.3..0i30l2j0i5i30l2.1211.6396.0.7060.19.18.1.0.0.3.1462.4184.11j4j0j1j6-1j1.18.0.les%3B..0.0...1c.1.aHqM0ISoHcU&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=7a7241402b8d17be&bpcl=35466521&biw=1280&bih=887&safe=on). Longstreet is widely credited with introducing the transverse (or traverse, it’s either two words frequently confused, or it appears to be spelled both ways in various sources) trench to what passed for “modern” warfare in his day. The point is that zig-zag trenches go back further than the ACW. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [October 23, 2012, 5:04pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/24 "2012-10-23T17:04:27Z")
> [@MonkeyMensch](#): > > Being at work and without cable I did not see the episode. What was their main thrust with the myth? Was it that the angle in the trench had to be sharp and neat? Or was it that it had to be precisely 90 degrees and not acute or obtuse? Just curious if you remember at all. Thanks. > > MM The big issue was sharp corners vs rounded corners. They did four tests: an open air ground level explosion as a control, a straight trench, a sharp cornered trench, and a round cornered trench. The cornered trenches were both right angles and they didn’t test any obtuse or acute angled trenches. They found a straight trench was really bad. It channeled the shock wave of the explosion and made it much more powerful down the length of the trench than it was at ground level. The two cornered trenches were still worse than ground level (although that would only be a factor if the shell landed in the trench). But they were much better than the straight trench. They found that the construction of the corners did make a difference. The sharp cornered trench was slightly but noticeably better than the round cornered trench. ---
**Author:** ![Hypno-Toad](https://avatars.discourse-cdn.com/v4/letter/h/b2d939/32.png) [@Hypno-Toad](https://boards.straightdope.com/u/Hypno-Toad)\ **Post date:** [October 23, 2012, 5:06pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/25 "2012-10-23T17:06:33Z")
**Sailboat** : Here’s some useful reading on the topic: \*The Renaissance at War \*by Thomas Arnold 2001 \*Empires of the Sea \*by Roger Crowley 2008 (It also addresses the attempted conquest of Malta, including siege tactics.) _Fire & Stone: The Science of Fortress Warfare 1660-1860_ by Christopher Duffy 1975 ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [October 23, 2012, 5:52pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/26 "2012-10-23T17:52:04Z")
I know. And yet reputable historians credit Longstreet for something…perhaps for re-popularizing? I don’t know. At some point you’re going to have to take it up with the history profession, not me. ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [October 23, 2012, 6:56pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/27 "2012-10-23T18:56:12Z")
> [@Little\_Nemo](#): > > The big issue was sharp corners vs rounded corners. They did four tests: an open air ground level explosion as a control, a straight trench, a sharp cornered trench, and a round cornered trench. The cornered trenches were both right angles and they didn’t test any obtuse or acute angled trenches. > > They found a straight trench was really bad. It channeled the shock wave of the explosion and made it much more powerful down the length of the trench than it was at ground level. > > The two cornered trenches were still worse than ground level (although that would only be a factor if the shell landed in the trench). But they were much better than the straight trench. > > They found that the construction of the corners did make a difference. The sharp cornered trench was slightly but noticeably better than the round cornered trench. Thanks. Interesting and somewhat counter-intuitive. I’d have thought that a sharp corner would have had some sort of prism-like refractive effect while a rounded corner would have been sort of diffusive. I guess that’s why we have Jamie and Adam on the planet. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [October 23, 2012, 8:58pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/28 "2012-10-23T20:58:57Z")
> [@MonkeyMensch](#): > > I’d have thought that a sharp corner would have had some sort of prism-like refractive effect while a rounded corner would have been sort of diffusive. I would think being soil that it would absorb better at a right angle; the shrapnel smacks into a wall of dirt. ---
**Author:** ![Dissonance](https://avatars.discourse-cdn.com/v4/letter/d/85f322/32.png) [@Dissonance](https://boards.straightdope.com/u/Dissonance)\ **Post date:** [October 23, 2012, 9:26pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/29 "2012-10-23T21:26:16Z")
> [@solosam](#): > > In general, the WWI trenches were quite effective. Check out some battles such as the 1916 Battle of the Somme. The Brits fired 1.73 MILLION rounds over the course of 5 days, (the world’s largest bombardment up that point) and accomplished diddly squat. It wasn’t the trenches per se that protected the Germans so well from the bombardment, it was the dug outs attached to the trenches that they were able to wait out the bombardment in. A major problem was also that the majority of the shells used in the bombardment were shrapnel shells which proved to be nearly useless. It was thought that they would be able to shred the barbed wire in front of the trenches, but nobody bothered to test to see if that would be the case; it wasn’t. From [wiki](http://en.wikipedia.org/wiki/Battle_of_the_Somme): > [@](#): > > Barrages in the past had depended on surprise and poor German bunkers for success; however, these conditions did not exist in the area of the Somme. To add to the difficulties involved in penetrating the German defences, of 1,437 British guns, only 467 were heavies, and just 34 of those were of 9.2" (234 mm) or greater calibre. In the end, only 30 tons of explosive would fall per mile of British front.[22] Of the 12,000 tons fired, two thirds of it was shrapnel and only 900 tons of it was capable of penetrating bunkers.[23] To make matters worse, British gunners lacked the accuracy to bring fire in on close German trenches, keeping a safe separation of 300 yards (270 m), compared to the French gunners’ 60 yards (55 m)—and British troops were often less than 300 yd (270 m) away, meaning German fortifications were untouched by the barrage.[23] The infantry then crawled out into no man’s land early so they could rush the front German trench as soon as the barrage lifted. Despite the heavy bombardment, many of the German defenders had survived, protected in deep dugouts and they were able to inflict a terrible toll on the infantry.[24] ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [October 23, 2012, 9:40pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/30 "2012-10-23T21:40:02Z")
> [@MonkeyMensch](#): > > Thanks. Interesting and somewhat counter-intuitive. I’d have thought that a sharp corner would have had some sort of prism-like refractive effect while a rounded corner would have been sort of diffusive. I guess that’s why we have Jamie and Adam on the planet. I would speculate that it’s because a shock wave reaching a straight cut corner hits the wall perpendicularly. The shock wave is reflected directly back onto itself and that creates a wave interference that dampens the wave. A shock wave hitting a curved wall reflects off at an angle. It may be diffused but it doesn’t interfere with itself. ---
**Author:** ![Bosstone](https://avatars.discourse-cdn.com/v4/letter/b/22d042/32.png) [@Bosstone](https://boards.straightdope.com/u/Bosstone)\ **Post date:** [October 23, 2012, 9:59pm UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/31 "2012-10-23T21:59:25Z")
> [@MonkeyMensch](#): > > Thanks. Interesting and somewhat counter-intuitive. I’d have thought that a sharp corner would have had some sort of prism-like refractive effect while a rounded corner would have been sort of diffusive. I guess that’s why we have Jamie and Adam on the planet. Your logic is mostly correct but applied in the wrong direction. Think about a corner with a 45-degree cut. That gives your prism refraction. A curved corner is just a variant of that. Both aid bouncing particles in turning the corner. With a 90-degree turn, most of the shrapnel/shockwave will hit the wall dead-on and either bounce straight back or stop cold. If some shrapnel manages to hit obliquely, it might round the corner, but with one parallel wall and one perpendicular wall, that’s not a lot. ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [October 24, 2012, 2:57am UTC](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569/32 "2012-10-24T02:57:06Z")
> [@Little\_Nemo](#): > > I would speculate that it’s because a shock wave reaching a straight cut corner hits the wall perpendicularly. The shock wave is reflected directly back onto itself and that creates a wave interference that dampens the wave. A shock wave hitting a curved wall reflects off at an angle. It may be diffused but it doesn’t interfere with itself. > [@Bosstone](#): > > Your logic is mostly correct but applied in the wrong direction. Think about a corner with a 45-degree cut. That gives your prism refraction. A curved corner is just a variant of that. Both aid bouncing particles in turning the corner. > > With a 90-degree turn, most of the shrapnel/shockwave will hit the wall dead-on and either bounce straight back or stop cold. If some shrapnel manages to hit obliquely, it might round the corner, but with one parallel wall and one perpendicular wall, that’s not a lot. Well put and thank you both. [Previous page](https://boards.straightdope.com/t/german-wwi-trenches-designed-with-perfect-90-degree-corners-did-it-offer-shrapnel-protection/638569.md?page=1)