[REQ] info on RL torpedo damage

[Arclight]

I'm interested in some data and opinions on torpedo damage on ships, in particular the size of the hole and the extent of damage beyond the area that was hit directly. Would damage be contained to the compartment it struck (let's assume it hitting midway between bulkheads) or would the bulkheads separating the compartment be likely to suffer damage as well?

Any chance of a torpedo striking on the bow or stern damaging the engines, maybe by transmission of vibrations?

How consistent is this damage? Would damage observed in 1 case be similar to damage observed on a ship of the same class with a similar hit, or would it vary quite dramatically?

[Sailor Steve]

Usually a hole from a torpedo is very large, and will span two or more compartments. Compartmentation on a modern ship will contain outboard sections that are smaller, just to help isolate the damage. Here is an account of the damage to SS Ohio, taken during Operation Pedestal, the supplying of Malta.

The Ohio was torpedoed amidships, were a huge pillar of flame leapt high in the air above mast height. Ohio seemed to be out of control; Captain Mason ordered the engines to be shut down, with all deckhands available putting out the fire with the deck water-lines. Lighted kerosene was bubbling up from the fractured tanks, while little gouts of flame spattered the deck on to a distance of thirty yards from the blaze. Fortunately however, the flames were put out and the tanker managed thirteen knots after being repaired. The blast destroyed the ship's gyro and brought the magnetic compass off its bearings, while the steering gear was lost, forcing the crew to steer with the emergency gear from aft.

A hole, twenty-four feet by twenty-seven feet, had been torn in the port side of the amidships pump-room. The blast had also blown another hole in the starboard side and the compartment was flooded. There were jagged tears in the bulkheads and kerosene was bubbling up from adjoining tanks, seeping in a film up through the holes in the hull. The deck had been broken open, so that one could look down into the ship. From beam to beam the deck was buckled, but the ship held together.

The whole story, including bomb hits and near misses (which also make holes in the hull, letting in more water) can be found here:
http://en.wikipedia.org/wiki/SS_Ohio

Unfortunately my copies of Conway's Warship series with pictures and descriptions of torpedo and shell hits are in storage at the moment, or I could give you a lot more information.

[THM]

I have a photo of the area after a torpedo hit somewhere. Gotta search it. Way different than just a hole. A lot of metal gets bend inward.
Bulkheads will fail if close by the point of impact. Either by direct explosive force or by rupturing due to physical forces like bending and tearing.

If the drive shaft gets damaged badly you are in a world of pain. Imagine a giant propeller shaft in a confined space torn free of its bearings...:o

Vibrations will cause damage. I recall reading that the German cruiser Ad. Hipper had to stop for immediate repairs somewhere between Scandinavia and England due to a faulty shaft bearing.

Water seepage will occur, too. After some time electric cables etc. will draw water like wick. Again, Hipper had to cut a lot of cables to fire control after some compartment down below had taken water to prevent massive shorts.

Cheers!

Chris

[alexradu89]

Since we're on the chapter of RL torpedo damage and such, could some of the more experienced guys tell us more of what depth should a torpedo be launched ? I had heard that the heavier the ship, the greater depth the torpedo must be launched, and what about weather, would rough seas affect torps launched at a small depth ?:salute:

EDIT: Here are some fantastic shots of HMS Thane's damage suffered from torpedo attack from U-1172. Just scroll down to the bottom of the page.

http://www.royalnavyresearcharchive.org.uk/ESCORT/Galleries/THANE_Gllery_2.htm

[Arclight]

A hole, twenty-four feet by twenty-seven feet, had been torn in the port side of the amidships pump-room. The blast had also blown another hole in the starboard side and the compartment was flooded. There were jagged tears in the bulkheads and kerosene was bubbling up from adjoining tanks, seeping in a film up through the holes in the hull.Impressive story on the Ohio. :up:

Pretty amazing that the force of the blast got directed straight through and out the other side. :o

So it's pretty safe to say that damage ranged far beyond the immediate area of the blast?

I know it's been said plenty of times, but the torpedoes in the game seem wimpy. Not by visual splash or damage value, but the area they affect. Hit the engine room in the center, and that's it, you take out that engineroom. What about, with a tanker or warship, the 2nd engineroom on the port/starboard side? Imho damage should be more widespread.

Thank you all for the replys, any more info is more than welcome. :salute:

[Sailor Steve]

A quick look through the "Allied Merchants Hit" section of www.uboat.net (http://www.uboat.net) gives the following:

Medium Merchant (5590 tons): torpedo struck on the port side just forward of the poop deck. The explosion opened a crack three feet wide across the deck, destroyed the interior compartments and flooded the engine room. The stern dropped 30°, apparently held in place by the shaft.
http://www.uboat.net/allies/merchants/ships/2220.html

15,000-ton liner took 1 torpedo to stop, but 3 more to sink, plus some shellfire.
http://www.uboat.net/allies/merchants/ships/739.html

A 10,000-ton tanker that also took 4 torpedoes to sink.
http://www.uboat.net/allies/merchants/ships/1843.html

15,500-ton liner sank after only one torpedo.
http://www.uboat.net/allies/merchants/ships/406.html

I know that sunk ships usually can't give proper damage reports, but I thought this would illustrate the variety of sinkings. I have info on a Japanese merchant that sank after being hit by a dud torpedo, and another that took 6 torpedoes and 10 hours of work by the submarine to finally put down.

[Bilge_Rat]

a typical U-boat torpedo had a warhead packing 280 kg (617 lbs) of TNT/HND/AL (a mixture of hexanitrophenylamine, trinitrotoluene and aluminum). That packs a lot of punch:

http://museum.gov.ns.ca/mma/wrecks/photos/full/41344.jpg

[THM]

Hey! That's exactly the picture I was talking about! :yeah:

[Bilge_Rat]

found this report of the torpedoing of the USS Kearny in 41 which has a lot of info on the damage:

http://www.researcheratlarge.com/Ships/DD432/1941DamageReport.html

http://www.researcheratlarge.com/Ships/DD432/1941ReportDD-432_02.jpg

[thruster]

suggest you may wish to google/you tube HMAS COLLINS torpedo test footage on the river class [mod. Leander] ex-?HMAS TORRENS.

Mk48 detonated under the hull. snapped it in two.

sorry, i dont have the link.

[Arclight]

ADCAP is a far cry from a G7 or mk 14. :lol:

Thank you all, especially the written reports give valuable info. It is invaluable to turn a "sim" into a sim. :salute:


In the game, radius is set to 3m (10ft) minimum and 7m (23ft) maximum. Max damage is applied to anything within 3m of impact, and damage drops off to a max radius of 7m.

I'd say the max radius needs to be extended to "simulate" damage beyond the impact zone (pressure wave entering hull through hole, shards of metal send flying, vibrations damaging engine and shafts, etc). :hmmm:

[trotter]

I'd say the max radius needs to be extended to "simulate" damage beyond the impact zone (pressure wave entering hull through hole, shards of metal send flying, vibrations damaging engine and shafts, etc). :hmmm:

I just don't know how much I trust the damage model of this game to be able to simulate differentiated compartmental damage. Everything seems to be on a "Damage Point" scale, and once the whole ship accrues enough damage points, it sinks. There seems to be no dynamic damage based on areas of impact. No flooding, listing, etc.

[Arclight]

Why do you think I'm asking?
http://i268.photobucket.com/albums/jj2/EZatHome/boxexample.png
I can tell you haven't tried BRF yet. ;)

[Regio Sommergibile]

Do you think it can be made ?

Such a damage like in some of those photographs seem to be too much complicated to be represented ingame... at least i think so :)

[urfisch]

the 3d damage ingame is a single file with textures, afaik.

[Arclight]

Visually yes, but we can tweak to make the damage model more realistic.

Expanding the range within which damage occurs is just 1 step though. Another would be tweaking the values for the zones (the boxes you see in the image above), which I did for BRF, and I think the whole HP system needs a rework. Already increased hull HP for ships so you stand a chance of sinking them through flooding, but the HP for the individual compartments need attention too, and the torpedo damage needs to be balanced to that.

Finally, you can rework the zones.cfg, the file which contains the values for the zones. Now, a lot of ships use the same zones, but in reality each type of ship has a unique behaviour. You could add more zone types in the zones.cfg and use Goblin to edit the zones used by the ship models, to get far more unique modeling and better behaviour.

[Regio Sommergibile]

Ok about that i had no doubts, but what about the 3D model changes ?

I support the idea explosions in SH suck, as well as parts of the ships that fly away like in hollywood explosions, but improving this seems really hard to me.

Btw i'm no expert at all. i was just asking for more info on his intentions because it's an eventual mod that i'd really be fond of

[Arclight]

I'm no 3D artist or particle master, so the visual stuff I leave to someone else. The actual damage modeling though, that is something I can work on.

[Regio Sommergibile]

I understand. Badly needed for sure ;)

[Taurolas]

the problem with realistic damage is that its impossible to estimate, if you hit a ship inbetween bulkheads with bulkhead doors shut then it would fracture / blow the bulkheads out with the blast preassure. if you did the same thing with doors open then bulkheads may still be damaged but some of that blast preassure would go though any openings within the boat and vent out somewhere...

luck of the draw if you ask me

[Regio Sommergibile]

Something missing to me is that there are no clear rules on targeting.

I always try to shoot under the chimney but it depends on vessels...this should be taken into account.

[Arclight]

the problem with realistic damage is that its impossible to estimate, if you hit a ship inbetween bulkheads with bulkhead doors shut then it would fracture / blow the bulkheads out with the blast preassure. if you did the same thing with doors open then bulkheads may still be damaged but some of that blast preassure would go though any openings within the boat and vent out somewhere...

luck of the draw if you ask me
Expanding the max radius kinda accounts for that; you can do vey little damage or a whole lot, depending on what damage comes up for the hit (ranges from 120 to 180, so pretty variable).
Something missing to me is that there are no clear rules on targeting.

I always try to shoot under the chimney but it depends on vessels...this should be taken into account.
Not sure I understand. If you mean it should matter where you hit, again, I point to BRF (it's in the sig). Project is underway for a while now, and affects all ships (at least the ones that needed work; escorts usually sink with 1 hit, so no real need there) but the torpedoes haven't been altered yet.

[Regio Sommergibile]

Yes i meant where to hit, because as now i don't think there some rule about it.

I didn't know your BRF mod changed this too ;)

[Arclight]

It changes the "weight" of flooded compartments, so you see much more effect from hits; listing, sinking by the bow or stern, etc.

Better, but want a more refined solution to be honest.

[Regio Sommergibile]

"Listing" ??

[Sailor Steve]

There are many accounts of single ships being finished off with one or more 'coup de gras'. It is unknown whether the ship would have eventually sunk without these extra torpedoes. What bothers me is the way the games (all of them) don't give you credit if you don't actually see the target sink. I wish a routine was in place that would keep track of whether the ship sank, and tell you if sank later or made it to port.

One of the oddities where warships are concerned is the compartmentation. There were several instances of anything from a battleship down to a destroyer losing part or all of the bow due to a storm or a torpedo or bomb hit, and the crew managing to seal off the forward bulkheads and make it to a friendly port with 20% or more of the ship missing. This could only happen if the bow broke off foreward of a sealable bulkhead, but it did happen several times.

The most extreme example I know of is the destroyer HMS Javelin.

The 5th British destroyer flotilla (Capt. Lord Louis Mountbatten), HMS Javelin (flag), HMS Jupiter, HMS Kashmir, HMS Jackal and HMS Jersey encounters the German destroyers Karl Galster, Hans Lody and Richard Beitzen while these were conducting an anti-shipping raid off Plymouth. In the gun/torpedo battle that followed HMS Javelin was hit by two torpedoes, loosing both her bow and stern. Only 155 feet of Javelin's original 353 foot length remained afloat and was towed back to harbour. Javelin was out of action for almost a year.
More than 2/3 of the ship gone, and she survived to be repaired and returned to service!
http://www.uboat.net/allies/warships/ship/4451.html

HMS Javelin Bow

http://i14.photobucket.com/albums/a325/SailorSteve/JavelinDamageBow.jpg

HMS Javelin Stern

http://i14.photobucket.com/albums/a325/SailorSteve/JavelinDamageStern.jpg

[sergei]

Listing

http://img15.imageshack.us/img15/2761/llltj.jpg

:DL

[Bilge_Rat]

Sailor Steve makes a good point about watertightness.

Warships, because of better design, compartmentation, damage control, better crew training, can withstand more damage, because the crew can quickly seal off the damaged portion from the rest of the ship.

A merchant men is designed to carry the most cargo in an efficient manner, so the compartments may be bigger and not designed to withstand torpedo damage. There is also the issue of maintenance. A 10 year old cargo ship may not be very waterproof through years of neglect, poor safety practices and may not be able to stop the flooding from spreading throughout the ship, even if the crew are able to seal off the flooded compartment(s).

For example, the USS California was hit by 2 torpedoes at Pearl Harbour. Because it was the flagship of the Pacific Fleet and was basically kept as a showrrom for the Admiral, it never received the required upkeep and was known to have poor watertightness. Even though all the bulkhead doors and hatches were closed, water was still able to seep into every part of the ship and she slowly sank over 2-3 days. This was in a 20 year old battleship. Many 10+ year old cargoships would have had the same issue.

[Arclight]

More than 2/3 of the ship gone, and she survived to be repaired and returned to service!
Only to be sold as scrap later on. :nope:

Can happen in the game too btw. :yep:


About ships sinking over time; best you can do is greatly increase the flooding times, but that really isn't a solution. I thought damage over time would be possible with the scripting, but I haven't seen anything that could be used to that effect. :(

[LukeFF]

The most extreme example I know of is the destroyer HMS Javelin.

There's also the example of the USS Blakeley:

http://uboatarchive.net/U-156BlakeleyMay72.jpg

http://uboatarchive.net/U-156BlakeleyMay57.jpg

More Photos (http://uboatarchive.net/U-156BlakeleyPhotos.htm)

War Damage Report (http://uboatarchive.net/U-156BlakeleyReport.htm)

[Arclight]

Draft before: Fwd. 10' 4-1/2" approximately;
Aft. 10' 11" approximately;
Draft after: Approximately the same as before.

That kinda puzzled me at first, but it makes sense if the damaged part is blown off. :hmmm: