Torpedos, extreme range and accuracy

[Von Due]

I am looking at the possibility of shots at extreme range, 5,000-10,000 metres with a reasonable probability of a hit and have done some calculations and looked at methods for getting target speed and heading, setting up for a plain 90* shots.

Needless to say, the accuracy needed is really touching on the limits of what can be achieved but here are some thoughts so far. Please chime in if you spot flaws etc!

Speed is if possible even more crucial to get just right and the 3.15 rule is, imo, too rough to give that exact speed for those ranges. I am looking at 730 metres per knot per 23 minutes 39 seconds. The time and distance per knot would have sufficient resolution to determine speed with a high level of accuracy, even in rough sea where target speed is yoyo-ing over short distances.

About target heading. I have looked at speeds of 7.5 knot and 12.5 knots range to impact point 10,000 metres, torpedo speed 30 knots. The way I reasoned and do correct me here if I'm wrong:

First, I calculated the time T in seconds it takes the 30 kts torpedo to travel 10,000 metres to the ideal impact point P. This is the ideal situation where I somehow managed to get target heading accurate and am on a perfect perpendicular course.

For a 12.5 kts target starting at torpedo fireing point A, in that same time, it will travel T x 12.5 x 1.852 / 3.6 metres.

I now have a triangle with two sides of 10,000 and T x 12.5 x 1.852 / 3.6 metres.

Now if I got the target heading wrong by +- 1*, that would mean the distance from P to true impact point P+ or P- is
T x 12.5 x 1.852 / 3.6 x tan 1*and the true distance traveled is
10,000 +- T x 12.5 x 1.852 / 3.6 x tan 1*

I now need the time it takes the torpedo to travel those distances, T+ and T- and I calculate how far the ship will travel in the same time.

By comparing true impact points to where the ship would actually be, I find that I will miss the aiming point by some 30 metres. The actual distance would vary depending on whether I missed by -1* or +1* but roughly 30 metres will do.

That means I should not attempt long range shots at targets at around 60 metres in length or less but for a ship or 100 metres or more, I should have a good chance of hitting if I aim at center.

For target speed of 7.5 knots, the possible error would be around +- 11 metres, meaning if the target is moving slow, I should be able to hit a 50 metres or more long target if I aim at center.

All this of course rely on accurate heading and speed calculations but the bottom line is, even if I get the heading wrong by 1 degree either way, I still stand a good chance of hitting at 10,000 metres.

Any inputs and corrections greatly appreciated!

[Red October1984]

Wow....I am sorry i cant help you...but i dont understand a bit of that. I wish i did. I wish i could figure out all of that. But, I dont. I just line up and shoot...

It'd be cool to one day, understand all that.

I have, on a few occasions, hit with torpedoes at 6000-7000 meters.

[Von Due]

The problem with long range shots was something I pondered when I played SH2. I was looking for a way to get the targets without having Superman, the X Men and the A Team onboard those Marvel Comics destroyers racing towards me wherever I was within medium range. IIRC, the graphics didn't allow for much sniping but now that I am able to identify ships at greater ranges I might have a chance.

I have only succeeded one or two times before in SH3 at 10,000 metres or so and only at high resolution but I had no good idea of why it couldn't be done a bit more consistently. A few things are certain. At those ranges I'm dealing with fractions of degrees and 1/10th's of a knot but it can be sorted to a pretty good level.

A rough sketch to accompany the first post

[Red October1984]

I close to about 2000-4000 before i fire. When i do fire, I set it up so that i either

1. Take out as many targets as possible

2. Make sure that i take out my one target

3. Can disable the most dangerous target

I have disabled several destroyers and then followed the High Value Target ships a good while and sink them. But, the third option is a bit harder than the first two.

A torpedo to the screws can do a lot to a destroyer.

[derrinurban]

To me the hardest part about extreme range attacks was the ship speed and actually firing the torpedo. The math is the easy part. You can get the ship speed close. You will probably never be 100% accurate but very close. Then you need to time you shot perfectly. Hitting the fire button precisely at the right time is almost impossible. Again you can be close but not perfect. Those fractions of seconds between when you are supposed to hit the button and do and the second for the torpedo to clear the tube make hits at that range lucky at best. IMHO

[HW3]

That plus if you are using steam torpedoes, the wake might be spotted and evasive maneuvers taken by the ship, which will also cause a miss.