What's a good sub attack range?

[uncleseano]

U.S sub making a torpedo run. What's a good range that skirts between accuracy to hit and best distance to escape at?

[rkiser58]

It all has to do with the angle on the bow to target and solution of the target. You will see the solution in the upper left. The angle is what you get if you press the Torps icon the lower the better. This is determined by your course to target. your torps have to be fired somewhere between 8000 and 1500 yrds. The closer the better. {it gives you a chance to build up your solution and angle] there is no real one size fits all range to fire. If you are firing on a big TF 5500. Cargo ships 2500. All that goes right out the window at night. It's doesn't really give you a good solution build at night.

[Amelia]

At night US subs can use their radar to get some pretty effective solutions, I like to close to 1,500 yards though since that and a correct ID + steady course can give 80%.

[uncleseano]

Ok super, thanks guys. I'll give it a whirl so

[Amelia]

Don't be afraid to knife fight the DDs at close range, only way to do it!

[MizuYuuki]

Originally posted by uncleseano:

U.S sub making a torpedo run. What's a good range that skirts between accuracy to hit and best distance to escape at?

You're guaranteed to get away if you fire from 4000 yds by enabiling silent running, submerging to max depth and going full speed at about 90 degrees from the launch point. The ideal launch point is when the target is 20 to 30 degrees off your bow (depends on target speed) and 5000 yds from your sub, and the gyro angle is 0 degrees. This way the torpedoes will go behind the lead DD and in front of the flank DD, and impact the target at 90 degrees from its heading. You can put 6 torpedoes into a BB using 1 degree spread from this distance under favorable conditions.

[JAKeller]

The overall deflection angle for hitting with sub torps is:

D = A - 90 + arctan (B/C/sin (A) + cos (A)/sin (A))
(Angles are in degrees)

Where:
A = Angle on Bow
B = Speed of target
C = Speed of torpedo

You'll want your base course to be Target Base Course ± AOB ± 180. This points your sub in the same direction the torps will go without deflection. The deflection angle D is then the bearing angle you'll want to fire at. Range is irrelevant at that point.

Example:
Target Base Course = 118 Your sub is off to the target's port
Target Case Speed = 14 kn
AOB = 70
Sub Base Course = 118 - 70 + 180 = 228º (You're to the target's port and you'll be firing to your starboard, hence -70 and +180. Reverse this if you're firing a chase solution e.g. from the target's stern quarters)
USN Mk 14 Speed = 30.5 kn
Deflection = 20.4º
Fire Bearing Angle = 228 + 20.4 = 248.4º

So time your fire when the target is between 248º and 249º to ensure a hit.

For the IJN, A = 90 works very well and is the easiest to set up. For the USN, that angle is harder to determine because the dud model isn't completely clear, though A = 70 seems to work well enough.

I've found that firing with a spread angle of 1º works if the range is under 2000yds and 0º if over.

[Grant]

With Japanese submarine, you have the option of approaching from the sides and still be able to hit almost any enemy ships within 3-4K. For the USN submarines, your best approach is from the front of the enemy task force to get within 1K-2K.
The main reason is due to the speed of the Japanese torpedoes of 40kn compare to the American MK 14 30kn.
If an AI CV or CA spots MK14 coming from the side or rear outside of 1K, it can simply outrun the torpedoes. BB ships also can dodge most of them, and with MK 14 dud rate, two or three torps making contact isn't ideal.
With the Japanese, the AI CV and CA will have a hard time dodging them if within 2K, while Allies BB have no choice but to launch lifeboats.