One Torpedo, One Ship?

[Bubblehead1980]

I remember watching a 5 part series via youtube a week or so ago about U boats, very good show.I remember one "Ace" was said to use one torpedo for one ship....were German torpedos the powerful? Would this work in U boat game? Im a fleetboat guy so U boat stuff is still mostly an unknown arena.Not starting the discussion but hoping DRM is dropped so I will buy SH 5

[Deep Dive]

If i remember well this was the moto of "Silent" Otto Kretschmer
Torpedoes were generally powerful enough to bring most ships down in most cases
There were many "duds" of course especially in the first years
Both Americans and Germans experienced various similar problems

[Sailor Steve]

American policy was to fire three torpedoes at most targets. Of course they carried 24 torpedoes, so they were ready for that.

Read Uboat.net's accounts of how many ships were hit by one German torpedoe and sailed away to tell about it. Also there are many accounts of one torpedo stopping the ship, and the u-boat giving it a 'coup-de-gras' several hours later. Or sank it with the deck gun. Or tried that and then delivered a second eel. And sometimes a third.

'One ship, one torpedo' makes a nice saying, but the German torpedoes didn't fare any better than the American ones did.

[Galanti]

It's an ironclad rule on U-56 right now in my Operation Monsun career, but only because she only carries five of them. I go for magnetic keel shots as much as possible.

In my RFB campaign, Christ, I'll empty the whole bow at one little Maru to compensate for deep-runners, duds and my general ineptness.

I think Steve's right, plenty of ships went down to one fish, but it was by no means the majority.

On the other hand, we'll never know how many went down to multiple fish where just one would have sufficed.

[Jimbuna]

http://www.modelshipmaster.com/produ...rines/U-99.htm

In the first four patrols of the U-99, Kretschmer started striking convoys at night on the surface, taking down merchant ships with highly accurate shots, using only one torpedo per target ship in order to save ammunition, and the quote "One torpedo ... one ship" is attributed to Kretschmer from around this time.

[Bubblehead1980]

Thanks for the replies.One thing I hope is possible in SH 5 is to be able to get inside the convoys as real U boats did.I never played SH 3, was this possible?

[Platapus]

Originally Posted by Bubblehead1980

I remember watching a 5 part series via youtube a week or so ago about U boats, very good show.I remember one "Ace" was said to use one torpedo for one ship....were German torpedos the powerful?

1943
Mark 14 torpedo (USN) 643 Pounds/292Kg of Torpex

G7a (German) 661 Pounds/300Kg Hexanite

Torpex consists of 42% RDX, 40% TNT and 18% Aluminum Powder

Hexanite or what the Germans called "SW39a" was 50% TNT, 10% Hexinit, 5% ammonium nitrate, and 35% aluminium powder.

Comparing explosives can be difficult. The term "more powerful" can be misleading. The term "Brisance" is used as a measure of how fast an explosive can reach its maximum pressure.

Explosives with lower Brisance well tend to push an object away (very low Brisance explosives can be used as a propellant). Explosives with a higher Brisance will tend to shatter an object.

Explosives with a lower Brisance will tend to have a longer explosive pulse (the duration of highest pressure). Explosives with a higher Brisance will tend to have a shorter explosive pulse.

So when trying to sink a ship with a torpedo, do you want explosives with a higher or a lower Brisance?

The answer is yes. Because torpedoes have the special advantage of being used underwater, the water can serve as what is called a Tamper. The inertia of water contains the explosive wave therefore increasing the duration (and incidentally focusing) the explosive pulse. What you want is an explosive that has both the effects of a higher Brisance (for the speed to get to maximum pressure) and the effects of a lower Brisance (for the longer duration of that maximum pressure). The trouble is that it is difficult to have both.......unless you are underwater.

The addition of Aluminum Powder to an explosive is an effective way to add the effect of a lower Brisance explosive to the existing higher Brisance.

As we learned in EOD school, a little pinch of powdered Aluminum is always a good thing.

Ok "professor" Platapus, you have used all the big impressive words, what the hell does all this mean?

Simply put, the ability to penetrate the hull of a ship is more affected by the higher Brisance of an explosive. But we don't need to penetrate the hull of a ship to sink it, all we need to do is separate the hull plates (think Titanic). This is more easily accomplished by using an explosive with a longer explosive pulse.

The Germans, in an attempt to economize, developed a combination explosive (Hexanite or SW39a) that while it had a lower total explosive power than Torpex (lower Brisance), the higher proportion of Aluminum powder turned that lower power explosive compound into a more effective explosive compound. Effective for this one purpose, that is.

This is why it is difficult to compare explosives. It depends on the compound and its intended use. This is why we don't just put C-4 in to every piece of ordnance. C-4 is good at what it does, but other explosive compounds are good at what they do. There is no universal "best" explosive.

So to reference back to the original question, yes the German torpedoes using SW39a were more effective at comprimising the integrity of the hull plates of merchant ships, despite being "less powerful" than US torpedoes using Torpex.

If your intended target is an armoured hull of a military ship, the story changes. To penetrate armour (as opposed to spalding the armour) you will need a higher Brisance explosive.

In this case, the US torpedoes with Torpex woudl be more effective at compromising the integrity of the armoured hull of a military ship..... assuming the damned Mark 14/Mark 6 even functioned.. but that is another story.

Probably more than you wanted to know. But when discussing the effectiveness of explosives, some background needs to be understood.

And we did not even touch on the secondary explosive effects or the depth of the explosive pulse.

[Sailor Steve]

Originally Posted by Platapus

If your intended target is an armoured hull of a military ship, the story changes. To penetrate armour (as opposed to spalding the armour) you will need a higher Brisance explosive.

In this case, the US torpedoes with Torpex woudl be more effective at compromising the integrity of the armoured hull of a military ship..... assuming the damned Mark 14/Mark 6 even functioned.. but that is another story.

This is where I disagree. It's my understanding (I've read some actual sources but don't have them handy right now, so "it's my understanding" is as far as I will commit right now) that tests were done during the First World War that concluded that hardened armor isn't really more resistant to a torpedo hit than mild steel. The armor was designed to resist 'point hit's from a shell coming in at supersonic speeds. What did help a little was the fact that the armor was much thicker than the usual 1/4-to-1/2 inch steel plates found on destroyers up through merchants, but the very weight of the armor meant that it couldn't be very wide, usually ending just a few feet below the waterline. This left the lower hull exposed, and toward the end of World War 1 the British started experimenting with TDS (Torpedo Defense Systems). These usually consisted of a 'bulge' of mild steel which was filled with some liquid, allowing the torpedo to rupture the bulge and not reach the hull. The magnetic detonator was originally created to counter that, since the bulge itself couldn't be made to wrap around the bottom of the ship.
http://www.navweaps.com/index_tech/tech-047.htm
http://en.wikipedia.org/wiki/Anti-torpedo_bulge

[Platapus]

Originally Posted by Sailor Steve

This is where I disagree. It's my understanding (I've read some actual sources but don't have them handy right now, so "it's my understanding" is as far as I will commit right now) that tests were done during the First World War that concluded that hardened armor isn't really more resistant to a torpedo hit than mild steel. The armor was designed to resist 'point hit's from a shell coming in at supersonic speeds. What did help a little was the fact that the armor was much thicker than the usual 1/4-to-1/2 inch steel plates found on destroyers up through merchants, but the very weight of the armor meant that it couldn't be very wide, usually ending just a few feet below the waterline. This left the lower hull exposed, and toward the end of World War 1 the British started experimenting with TDS (Torpedo Defense Systems). These usually consisted of a 'bulge' of mild steel which was filled with some liquid, allowing the torpedo to rupture the bulge and not reach the hull. The magnetic detonator was originally created to counter that, since the bulge itself couldn't be made to wrap around the bottom of the ship.
http://www.navweaps.com/index_tech/tech-047.htm
http://en.wikipedia.org/wiki/Anti-torpedo_bulge

Absolutely! The science of designing armour plating is a most complex topic. Similarly to explosives (in that there is no best for all purposes) there is no "best" armour composition. What pretty much everyone learned during WWI is that it is not simply a matter of finding the "strongest" metal compositions and then increasing the thickness.

Armour plating needs to be designed to resist a particular type of attack.

Against hardened armour piercing ordnance, thicker more dense armour is good.

Against explosives, less dense armour that can flex is good.

This is actually a criminally oversimplified explanation of an incredibly complex topic of armour design and construction.

Actually armour is made up of layers with different metals as distinct layers with other layers made of different metal compounds. It is an interesting topic.

I am afraid I am more familiar with blowing stuff up than designing stuff to resist being blown up. But excellent points Steve.

One can't discuss the effectiveness of torpedoes without taking into effect the hull/armour compositions.

[Frederf]

I've heard that an "under the keel" shot was good for causing many leaks at riveted panel borders all over the ship which were hard to repair before maybe a long duration sinking. Is this true?

[Hartmann]

well, usually the explossion blast broke the keel and the ship splits in two after the up and down movement.

[Hartmann]

In shV it´s not a problem, you can always use the increase explossive power hability of the weapons officer.

perhaps firing a modified torpedo with doble amount of explossive or two tied with duct tape...

[longam]

As long as their shields are down, one torpedo should do it...oops wait I just watched star trek new movie.

[tater]

I went through that u-boat database when this subject came up before, and found that the number of fish required to sink ships of similar sizes was actually MORE for german torpedoes in most cases compared to the Mark 14. ( I also went through every single US submarine torpedo attack of the war and made a database of them).

It was not at all the answer I expected, but it's what the reports/narratives spit out if you start counting up 1 hit sinkings vs 2 or more.

The guy I was arguing with, BTW, counted ships that made it back to port, but were written off as losses a "sinking" to try and bolster his 1 hit, 1 sinking notions. Not so, writing a hull off is an economic decision, allies were making so many hulls, repair cost more than scrapping (just like remodeling costs are more [per ft^2 than new builds for houses).

Some links:
Below link I compared warship attacks, virtually no difference in numbers of fish to sink between u-boat and fleet boat attacks that matters.
http://www.subsim.com/radioroom/show...2&postcount=53


Below, I compared Hog Islander sized targets, and the US sinking rate with only 1 hit was 88%.

http://www.subsim.com/radioroom/show...1&postcount=67

The German rate (from u-boat.net) to ALL attacks on Hog Islanders was 94% successfully attacked were sunk. Since it gives no fish count, that 6% difference accounts for attacks with 2 fish, AND deck guns added in. Even if you assume none were every attacked or hit with more than 1 fish, and none were ever attacked with the DG, that difference is well within chance (or sea state differences between the N Atlantic and PTO).

I later went through all the narratives for the hog islander attacks and figured out the hits per sinking:
http://www.subsim.com/radioroom/show...6&postcount=74

ONly 50% sank with 1 hit compared to 88% of jap ships of similar tonnage (I actually counted ships larger than the hog islanders, too, since most of the similar jap ships were slightly larger than that).

For late war, I checked Liberty Ship stats, I read every Liberty Ship attack u-boat narrative and:

Liberty (~7k t) vs U-Boats, 18.18% sunk after hitting with 1 torp (1944)
7k t jap vs Fleet Boats, 79.17% sunk after hitting with 1 torp. (entire war)

[Rockin Robbins]

Originally Posted by Hartmann

In shV it´s not a problem, you can always use the increase explossive power hability of the weapons officer.

perhaps firing a modified torpedo with doble amount of explossive or two tied with duct tape...

There you go! Use the arcade game feature! What part of the word "simulation" got lost here?