What kind of torpedos are needed to sink Jap AP's?

[doomonyou]

I regularly use my subs to inderdict Jap landings at various places in the game like Gili Gili, Buna, and Guadacanal. I will often have a naked base, and two or three subs there. Regardless of what you think of the tactic, I have noticed that many times Jap AP's will get torpedoed, even surface shelled. I have on several occasions had AP's get away with two torps in them, and almost every time with just one torpedo. Given Jap damage control and the fact that a loaded AP is already running low in the water, wouldn't one torpedo often be sufficent to sink the thing? Would two almost always do the job (in fact I would think two would do it almost immediately)

Am I just missing something?

[Spooky]

Welcome to the board

2 things :
- If Fog of War is on then the report of your subs can be a little optimistic
- Sunk opponent ships are not shown immediately in the "sunk ships screen" - you will have to wait between 0 to 60 days for them to appear in this screen

BTW, one Jap AP hit by 2 torpedoes is nearly always doomed

Spooky

[doomonyou]

:rolleyes: I didn't realize that fog of war affected the combat display, so this the naval combat display (torpedo hits, belt armor penetration, severe engine damage etc) represents the report of my sub and not neccesarily the actual damage done to the enemy vessel? Because I do occasionally get a "Blah Blah Maru sinks" message and I assume that those reprts are fogged since a ship could limp off or the escorts drive me away before a good damage assesment can be made.

thanx for the reply....

As a side note nothing welcomes a jap invasion force to Gili Gili quite like four S boats just sitting in the hex bored from weeks of waiting...

[Scouters]

I can second that about the effect of fog of war. A percentage of your bomb and torpedo hits are "false positives" where a hit is reported but did not actually take place.

Its interesting to note that this goes both ways. Playing the Allies I watched in horror as the Hornet took a torpedo from an IJN sub. The next turn I examined the ship roster and the Hornet wasn't even scratched!

-Scouters

[Spooky]

Yep, combat reports can be a little optimistic ... or sometimes very optimistic in some LBA bombings

If you get the message "xxx Maru sinks" then you can assume she is REALLY sunk - you will get the confirmation in the information screen a few days later.

However, I often learnt that I had sunk several APs only via the ships sunk list in the information screen - I never got the message "xxx sinks" because there was no US ships or planes to report it

Spooky

[wmtiz]

Greetings, welcome aboard.

The Fog Of War can be misleading when enabled. It is one of the more realistic ways of playing a wargame in how it is implemented in UV. What you see in the combat animations and the after-action combat reports are what your forces claim to have done, be it planes shot down, bomb or torpedo hits on enemy ships etc.

One way to get a feel for what happened, say you have your three subs sitting in the same hex as Gili Gili and a Japanese amphib force arrives in the hex and you get some combat animations showing torpedo hits being scored on the Japanese APs but no reports of any sinking. If there is no followup ground attack against your base, it would indicate the APs were either driven off and are retiring away from your base (in which case you might detach one of your subs to try to hunt down and finish off cripples) of have sunk and will be reported as such at a later date.

That is a rather simplistic example of what can happen with the Fog of War activated. Many times a Japanese ship may be heavily damaged and will sink on its way back to Truk. In one of my recent scenarios, I have seen the Japanese CV Shokaku sink two hexes away from Truk several days after a carrier strike showed several bomb hits on it just off Guadalcanal.

The nice thing about the Fog is it works both ways, especially in a PBEM game. I assume it also has some impact in a game versus the AI. I have seen the AI send in an amphibious force the day after an exchange of carrier airstrikes near Lunga/Tulagi in which my carriers took some hits. Not enough to stop air ops but the Japanese pilots may have "claimed" to have sunk both of my carriers, therefore, the AI sent in the amphibs into what should have been an area "safe" from Allied CV airstrikes. They got a nasty surprise when 70+ SBDs showed up and blew them out of the water.

[Admiral DadMan]

Originally posted by doomonyou
Would two almost always do the job (in fact I would think two would do it almost immediately)

Am I just missing something?

US torpedoes weren't very powerful (see below), so one torpedo would do damage, but not often enough to sink even a lightly armed Maru.

Originally posted by doomonyou
What kind of torpedos are needed to sink Jap AP's?

Ones that explode.

USN's "S" Class boats (i.e., S-36, etc.) carried the Mark X torpedo with a 500lb warhead and were reliable.

US Fleet boats carried the Mark XIV also with a 500lb warhead. These were longer ranged and faster, but they had 3 defects:

1. They ran deeper than set (corrected on/about 1Aug42)
2. The "Magnetic Activation" feature that was supposed to explode underneath a ship did not work (Corrected Jan/Feb 43)
3. The Contact Exploder was too fragile, hence all the duds. (Corrected July43)
   [/list=1]IJN subs carried the Type 95, MOD-I with a 900lb warhead, and later MOD-II with 1,210lb warhead.

[mdiehl]

The US torpedo warhead was more than sufficient in use to sink any thin-skinned Japanese vessel displacing <2000 tonnes with on ehit and <5000 with two hits. Its warhead weight was lighter than the IJN but that's not particularly relevant. More important are the qualities of the targets againstw hich they were used. Also, it was about 100 lbs lighter than the highly successful G7 series used by the Germans. So, IMO the *entire* problem was getting a good detonation next to the hull.

[Admiral DadMan]

Originally posted by mdiehl
The US torpedo warhead was more than sufficient in use to sink any thin-skinned Japanese vessel displacing <2000 tonnes with on ehit and <5000 with two hits. Its warhead weight was lighter than the IJN but that's not particularly relevant. More important are the qualities of the targets againstw hich they were used. Also, it was about 100 lbs lighter than the highly successful G7 series used by the Germans. So, IMO the *entire* problem was getting a good detonation next to the hull.

Agreed.

Also factor in the spot on the hull where the torp strikes the ship, and you get a different effect. A hit in the bow is less serious than one from midships toward the stern.

[Didz]

Not sure it helps but I can certainly vouch for the fact that AP's can and do survive torpedo hits from US subs.

About the only thing I notice that sinks everytime are the AG's.

Incidently it might not be a bad thing if the AP was fully loaded and low in the water when hit as at least then by lightening the load they may be able to raise the damage above the waterline.

I have also noticed that some IJN ships can limp almost half way back to Truk before finally losing the damage control battle and sinking below the waves.

BTW: This is based on playing with FOW switched off.

[HARD_SARGE]

Hi Guys
with FOW on, one thing I watch for after strikes on AP's, is any reports of men killed or TF picking up men from the water, I seem to get lots of reports of the men being picked up and no report of the ship sinking

oh and that is a cruel sound effect when you sink a AP loaded with troops in a surface battle, you get to hear the men going into the water

(do think I stopped the Savo Attack in my first game, as a sub "sank" a AP in Shortland, and TF 2 was reported to be picking men up out of the water, believe it burned up it's movement points by doing so, and was not able to react to my landings)

btw, I love the gun Duels with AP, they got some great gunners on them ships

HARD_Sarge

[juliet7bravo]

Ya'know, this is something else the AI does that might need looked at. It invariably sends badly damaged ships off on that long (and often fatal) trip to Truk, instead of stashing them somewhere till the damage gets reduced to something survivable. In the course of an entire game, that adds up to alot of sunken ships, a good number of which could have been saved.

[Admiral DadMan]

Originally posted by juliet7bravo
Ya'know, this is something else the AI does that might need looked at. It invariably sends badly damaged ships off on that long (and often fatal) trip to Truk, instead of stashing them somewhere till the damage gets reduced to something survivable. In the course of an entire game, that adds up to alot of sunken ships, a good number of which could have been saved.

I was doing the same thing when I first stated playing. I lost several ships because I would send them back to the Rear Area Waystation (Noumea/Truk) instead of parking them at a fwd base to stabilize them. Now I do that automatically, until the FLT/Fires are gone.

[HARD_SARGE]

Hi J7B
I not so sure about that, in my battles for Shortland, the AI would send in ships and I would pound on them, and it would put them into port (had a really badly damaged BB go to port and lasted over 2 months there)

of course, if they did not get sunk during air attacks, they would end up trying to make the run home later, and not make it, but it did put them to port

HARD_Sarge


then again, the battles were fought right in the Harbor area or on the way to the Harbor, so that may of helped the AI to decide to use the port

[thantis]

I've seen the same thing at Shortlands Is. After beating up on several Japanese bombardment task forces, I sent in my level bombers to hit Shortlands port.

I started getting hits on BBs, CAs, & DDs that were parked there (probably until flotation damage was fixed enough for the load road back to Truk).

The AI also gets credit for not sending back ships to Japan if the strategic picture is bleak enough - meaning it holds onto ships (even if they're damaged) if it thinks they will be needed to counter my attacks.

[Supervisor]

Originally posted by juliet7bravo
Ya'know, this is something else the AI does that might need looked at. It invariably sends badly damaged ships off on that long (and often fatal) trip to Truk, instead of stashing them somewhere till the damage gets reduced to something survivable. In the course of an entire game, that adds up to alot of sunken ships, a good number of which could have been saved.

I've noticed this as well. It happens on both sides. I've had an AP hit hard south of Port Moresby (as the Allies). It was about 7 hexes out of Cairns, home base Brisbane and the computer automatically detached it and set it to go to Noumea (some 33 hexes or so away). I've had Japanese ships badly damaged around Gili Gili which route themselves back to Truk rather than Rabaul or Shortland (or Gili Gili for that matter, which was Japanese controlled).

The computer does this with many severely damaged ships on both sides, human as well as AI (it seems to want to get them where it can send them back to Pearl/Japan and doesn't consider damage -- other than in deciding to retire to Noumea/Truk in the first place). It should route the ship(s) to the nearest friendly large port (size 3+ maybe) to try to control the floation/fire damage before routing the ships on to Noumea/Truk. I've seen too many of the computer's CVs sink while heading far across the sea rather than head for closer safe anchorages.

[dgaad]

The contact exploder problem of the Mark XIV torpedo was the most serious and elusive problem of the several afflicting this torpedo. It almost didn't get fixed at all.

The Navy ordnance department blamed the Sub fleet arm for the lack of effectiveness of the torpedo, claiming that they were simply missing the target. It took dozens of eyewitness reports from sub commanders who observed a splash against a enemy ship without the subsequent explosion to convince the ordnance guys to even do a test.

Without any help from the Ordnance department, the Sub officers eventually figured out how to get hits with the torpedo. Angular impact.

The reason for the failure of the contact exploder was relatively simple, predictable, and stupid. It was of poor quality.

The contact exploder mechanism was a prime charge mounted on a dual rail. The exploder was supposed to be driven back along the rails to the main charge, where the whole thing would then explode. However, the rails were so fragile that they tended to collapse with a direct angle hit (within a range from a 90 degree angle), sending the exploder charge in a random direction, or not sending it at all because it would get wedged on the collapsed rails.

An angular hit, one where the torpedo struck the target at a 30 degree plus angle, would direct more of the kinetic energy to other areas, and the rails tended to hold up better here, resulting in more explosions. By about November of 1942, most sub commanders would position themselves to get an angular strike on the target, rather than a low deflection strike, resulting in more hits. The rails were still the same, and they still resulted in duds, but at least there was some "workaround".