Realtistic underwater damage to hulls

[SSI01]

I've seen a few posts on threads herein where at least one mod is discussed that provides enhanced torpedo damage to a ship's hull - i.e., makes the hole in the hull bigger. This in turn begs the question: which one is inherently more accurate re: the size of the hole in the hull - stock or the "enhanced," which may in fact be a reality upgrade.

Dry dock photos I've seen of torpedo damage to ships' hulls show holes that would swallow a Pennsylvania Dutch barn and, when one compares this to the holes caused by torpedo hits in the stock version, the stock holes seem to be a bit small.

So - does the "enhanced" torpedo effect mod more accurately reflect reality - or does that of the stock game?

[TorpX]

Originally Posted by SSI01

So - does the "enhanced" torpedo effect mod more accurately reflect reality - or does that of the stock game?

The visible 'damage' you see is not related to the damage points the target ship suffers. It is merely a graphical decal that shows up in the game - iow, eye-candy. You can sink a ship without seeing any hole in the hull, and you can make big holes, without sinking the ship.

[SSI01]

OK. I've noted the "no holes" issue before, that seems to happen when torpedoes strike a target's hull fairly close together. You'll get one hole but nothing - not an enlargement - for the second hit, nor any hint of additional internal damage (visually) for that close-proximity second hit.

Thanks.

[Scarredclown]

Today i got Lucky, the weather was perfect and i found a large modern tanker without any escort. I put three torpedoes in it, a lot of shells and it was going down sooo slow. Isnt that a lot for a tanker ? Three torpedoes ?

Does i have to hang around to have credit for it ? it seem to be a waste of time...

[Sniper297]

Could be dependent on a mod you're using, some have sinking mechanics built into the mod. Stock game the big 10,000 ton tanker usually takes two fish, sometimes one will do it, sometimes it takes 3 or 4.

This is realistic - an empty tanker sailing in ballast has a lot of airtight tanks filled with air. A full tanker has tanks full of oil or gas, which is lighter than water per gallon, so will also float after several hits. Unless the cargo is set on fire, of course, in real life some tankers took 7 or 8 hits and stayed afloat long enough to be saved, others exploded like an A-bomb from a single hit inducing a secondary explosion from the extremely flammable cargo.

Size of holes, I made the "bang for your buck" more as a "what we should have had" mod than any kind of realism. The history of US torpedoes is a dismal SNAFU of bureaucrats and defense contractors screwing up everything they got their hands on. Just before the war the Mark 14 was increased from a 400 pound warhead to a 500 pound warhead, increasing the bang but inducing the depth problems since they never compensated for the additional weight. Eventually US torpedo warheads increased to 600 and 800 pounds by the end of the war, meantime the Japanese had the Long Lance with high speed, long range and a 1000 pound warhead at the very beginning of the war.

So in my opinion the damage done by the stock torpedo is realistic, but unlike real life you get zero credit for damage, so if the target steams off over the horizon at 25 knots with 4 fish in him, you just wasted four torpedoes for nothing. So I cheat.

[SSI01]

Sniper 297 - excellent observations. As smart as they were (or thought they were), the "specialists" in BuOrd just seemed to let that elementary principle of physics get by them - if you have something hanging on the front end of your torpedo that's heavier than what originally used to be there, OF COURSE it's going to run deeper and compensation for the extra weight should have been added. Wonder what they were thinking?

We all know about the influence exploders and what a fiasco they were. Their multiple failures, plus those caused by the impact firing mechanisms, should have been grounds for at least a COI and possibly a court-martial. Those failures were costing lives. At the very least whoever was behind these problems, once made manifest, should have been relegated to something like running a backwater Navy installation in the middle of the Kansas prairie for the balance of WWII - then retired one-rank lower immediately after the war.

As I recall one of the Adms involved went from BuOrd to running the submarines out of, I think SOWESPAC where he used to give the captains who disabled the magnetic feature (and got hits, BTW) absolute hell in their patrol reports, even after a successful patrol, because they didn't use his pet feature. What a jerk. Wonder how many of them had their careers ruined by this guy and his devotion to his pet gizmo that should have been extensively tested pre-war, secrecy or no. I've got no sympathy at all for brass that pull stuff like this.

[Sniper297]

Court martial? Nah, shoulda been hung from the yardarm.

Guy you're talking about was Christie. In his defense;

1. Bureau of ordinance and the one and only manufacturer were supposed to be cranking out mark 14s like there was no tomorrow, but were so slow in production they were delivering less than half the number promised. First two years of the war the mark 14 was not only flawed, it was in short supply.

2. With the low power of the warhead, the magnetic exploder was the best way to conserve torpedoes by doing more damage per torpedo - if it worked as advertised.

3. Christie and other admirals were getting false reports from skippers who (1) falsified or exaggerated damage and sinking claims, and (2) disabled the magnetic exploders, set the fish to run shallow, then lied about both in their reports.

So Christie and the others were basing their decisions on logistics (trying to avoid running out of torpedoes) and false information from subordinates.

However, the flip side - the Germans and British had both tried magnetic exploders, discovered the big flaws in the theory itself, and gave up the whole idea long before Pearl Harbor. USN had access to that before the war started, so the whole gang should have been keelhauled.

My mod;

http://www.subsim.com/radioroom/down...o=file&id=4380

I use the first one;

1. UStorp125 - same explosive power as stock, but with damage radius increased to 125%

Which makes a slightly bigger hole, spreads the lowest damage effect out to involve more compartments, but gives only a slight advantage over stock.

[SSI01]

Sniper - To me this begs the question: Why was the German magnetic influence mine so effective against British shipping, so much so that surface ships were degaussed during WWII to counteract them? If that magnetic influence feature could be made to work with a mine, why didn't it work with a torpedo?
EDIT: Weren't most of the mines laid by US submarines and B-29s around the home islands in 1945 magnetic influence mines?

BTW I'm going to link with your mod and install, then give report.

Now just southeast of Kyushu after riding out a whopping storm - 30-foot waves at least, blinding rain, zero visibility - had to let two fat, slow convoys go by, no torpedo would have run accurately in seas like that. I could have made surface attacks with that visibility, however, I'd have been launching the fish into the air half the time!

[Sniper297]

German mines were more effective because (1) they were at a fixed depth, and (2) in a fixed location. The earth's magnetic field varies all over the scale even in the same region, Bermuda triangle for example has many large deposits of iron ore under the seabed that makes compasses, magnetic anomaly detectors, and magnetic influence exploders go haywire. Even without degaussing though, the magnetic mines had a failure percentage that was pretty high, even if not as bad as the torpedo magnetic exploder.

Even in regions without large disturbances the magnetic field around a ship is smaller when it's running parallel to the earth's magnetic field than it is when running perpendicular - in other words a ship running north or south will need to have the torpedo set for a depth closer to the keel to have the magnetic influence exploder activate, one running east or west will have such a large field it will set off the warhead 100 yards away - the main reason why there were so many prematures that the captains claimed as hits, it looked like a hit and exploded about the right time after firing, must have been a hit. But it wasn't. The few that worked were a matter of luck and the right combination of target course, size, how recently it had been degaussed, distance from the north pole, local magnetic variations, etc. That was the whole problem with the theory itself, what worked in tests off Nantucket needed a different sensitivity setting in the North Sea (the magnetic north pole is actually in northern Canada) and the distance under keel that worked for a destroyer would be too close for a battleship, which has a larger magnetic field and would require more distance under the keel to avoid a premature. Assuming the same course, if the destroyer was going east and the battleship heading south the destroyer could have a LARGER magnetic field than the battleship. Move the whole smash to the South China Sea and all bets are off, you're much further from the north pole and the variation is completely different so the sensitivity of the exploder will need to be cranked way up. Which will cause a lot more premature explosions, numerous reports of the warhead going off immediately after the 400 yard arming run, set off by the magnetic field of the sub that fired the torpedo.

When my squadron (Helicopter AntiSubmarine Squadron 75) was deployed ashore at NAS Lakehurst, NJ, we did a lot of practice MAD runs on the wreck of the Andrea Doria. Large passenger ship, known location off New York harbor so easy to plot from landmarks, good training for new AX and AW rookies. Even so the needle spike on the MAD recorder varied according to the time of the year and the weather, and sometimes needed to tweak the sensitivity. Exercises down in the Bahamas against actual subs was a different story, constant false spikes and constant fiddling with the sensitivity of the detector.

AFAIK there was no adjustment for the Mark VI exploder for the Mark 14, and the whole thing was so top secret there were no manuals even for routine maintenance anyway.

[SSI01]

Thanks - best explanation and in-depth discussion I've seen. If even half this stuff was known to the powers that be in the 30s, before the war, it makes one wonder why so much effort, brainpower, and funding were all wasted on it. So many variables there's no definitive way this thing could work given the technology of the 1940s - or even today. Reminds one of Sir Robert Watson-Watt and radar in Britain. He also built many other electronic devices for Britain in that way, along with many others. I can't remember the name of the scientific establishment in Britain that experimented with and tested this stuff, but they had a motto - "Second Best Tomorrow." They meant by that simple phrase that they could come up with something quick & dirty that would work right away but wasn't too refined; you could have the very refined gear in two or three months if you wanted, but of course if you waited the other side would be passing you up by then. How it applies in this matter is, to me, the contact exploder's problems were finally cleared up, after overcoming resistance from BuOrd, with a few weeks of serious application of effort and creative thought. The Navy finally got an effective contact exploder and it was a war-winner. You couldn't say the same thing for the magnetic exploder. It would have been better to ignore it and expend the effort on a reliable contact exploder, the sensitivities of certain ordnance "gurus" be damned. Once again, the quest for the "perfect" overcame the dire need for the "practical."

[Sniper297]

Recommended reading if you can find a copy, SILENT VICTORY, which covers all the screwups in the first two years. Particularly critical of Christie and bureau of ordinance for ignoring all the evidence the Brits had learned the hard way, really no excuse for refusing to deactivate something that our far more experienced allies had already proven worked less than 5% of the time and only in perfect conditions.

Some other reading;

http://www.ngdc.noaa.gov/geomag/declination.shtml

http://www.uboat.net/allies/technical/mad.htm

When I was on active duty (late 70s early 80s) MAD was more sophisticated and effective than the WWII stuff, but we still had to deal with all the quirks of the earth's magnetic field and double check everything with sonar.

[Sniper297]

Back on topic, stock mark 14 damage radius is 3 to 7 meters, so max hole size about 40 feet. Lowest yield "bang for your buck" mod is 125%, 8.75 meters max, so a hole about 50 feet in diameter.

While hacking the campaign EastAsiaCampaign.mis (the one with all them drunken lubbers in the mini troopships that run around in circles) I added my own task force with a Yamato escorted by 6 destroyers, running a pattern around the Philippines. Good way to test the damage effects, since I made the mod I know where and when to intercept on each patrol.

Usually it takes 8 to 12 of the UStorp125 mod mark 14s to sink Yamato, but it is random chance. Usually I set up at a 45 degree angle to the track facing away from the track so I can fire the stern tubes first, then go to full speed and turn into the track to fire the bow tubes. On one attack I hit the "sweet spot" with the second fish, between the two forward turrets, setting off a huge secondary in the main forward magazine which blew the whole thing up so I didn't need to use the bow tubes at all. Most recent attack I had no luck at all - 8 hits (sargo with 4 bow and 4 stern tubes) then dive deep to reload, 8 more hits, more reloading, then two more. Total of 18 fish required that time, pretty close to realistic in my opinion.

Sometimes a single hit will sink a Takao heavy cruiser, usually 2 hits are enough, sometimes 4 or even 5 are needed. The random chance subroutine is actually pretty realistic.

[SSI01]

I've got both vols 1 and 2 of Silent Victory, one of my most valued books. It's more than a book, it's a testament.

Somewhere in the dim recesses of my mind I seem to recall the ONR having at least three P-3s on strength that spent a lot of time in the air around the world conducting research on the earth's magnetic field. I think the name of the endeavor was "Project Magnet," oddly enough. I now understand why such detailed studies were undertaken.

I believe there were also some MSC ships that conducted detailed magnetic research as well.

EDIT: Installed your "buck" mod. I am using the 125% option only, the lowest-powered one. Even so I get a whacking great "bang" when the thing goes off, and the hole is somewhat larger although not enormously so. Did you change the sound of the torpedo detonation? Didn't know Yamato's sweet spot was between turrets 1 and 2. My experience has been it takes between 9 and 10 torpedoes to sink that ship, and that in the "single mission" menu. I haven't run across the ship on the high seas yet in my campaign.

"Madman, Madman!"

[Sniper297]

No, I did a few sound mods but nothing for explosions, and no sound files at all in "Bang for your Buck". In fact the only file is \Data\Library\Torpedoes_US.zon with five different versions of that one file. Possibly you were closer than usual when it hit.

As for Yamato, also applies to other BBs and CAs - a lucky hit in the magazine is often all it takes;



Works best on anchored ships in harbors since it's chancy to actually hit the exact spot you're aiming at with a moving target that's gonna speed up or turn when they see the wake.

[Longknife]

Hey Sniper,

Does the damage mod you are referring to change the reliability of the torp? While I find the duds & deep runner infuriating (I sent 3 under the keel of a Nippon Maru last night) I believe they are a important part of the sim.