Anti-Aircraft torpedoes

[Pisces]

Originally Posted by in_vino_vomitus

...
Yesterday, trying to intercept a Typhoon, all I got was a weak 50Hz line on the TA Narrowband. I used MoBo to do some independant TMA and it gave me a range result of about 200,000 yards - I immediately scrapped that result on the assumption that it was way too far - anyway I lost the thing and when I finally conceded and hit Show Truth, the thing was 97 miles away.

Wow, must have been the 3rd convergence zone.

[in_vino_vomitus]

Originally Posted by Pisces

Wow, must have been the 3rd convergence zone.

I'm not particularly knowledgeable about this, but I'd say not. There was no layer and the water was less than 1500 feet deep. I know that VLF propagates further than any other frequency band and it was right on the limit of detectability - Also there was nothing else in the area, so I'd say it had to be direct path - but I'm prepared to be contradicted by someone who knows these things better than I do.

If it makes a difference I was playing with the LWAMI mod, which I understand has removed the caps on detection ranges...

[OptimusX]

What probably happened is the "surface duct" phenomena. First:

1. In warm water (positive gradient) sound bends upwards.
2. In cold water (negative gradient) sound bends downwards.


Then:

1. Sound is radiated from source in all directions.
2. Sound radiating downward from from source will bend upwards.
3. When it hits the surface, it is reflected in a downward direction.
4. When you have warm water (positive gradient) the sound will bend upwards again.
5. The sound will hit the surface, is reflected downward, and the process repeats.

That's a "surface duct" and is probably the mechanism of your long detection range.

You take advantage of the surface duct when you are in shallow water yourself.

[in_vino_vomitus]

Thanks I've heard the term used, but I didn't understand what it was. I can see I need to learn a lot more about this....

[banryu79]

Originally Posted by in_vino_vomitus

Thanks I've heard the term used, but I didn't understand what it was. I can see I need to learn a lot more about this....

Hi in_vino_vomitus, I do not know if you already know this page (I bet many players of DW here know about it) but you can read and learn a ton of useful stuff from here:
http://fas.org/man/dod-101/navy/docs/es310/syllabus.htm

Of course the "U/W ACOUSTICS & SONAR" section is the one of interestest, but if you can spare the time and patience I suggest you to read form the start, "COMMUNICATION SYSTEMS".

Very intresting stuff, worth the time

[in_vino_vomitus]

Originally Posted by banryu79

Hi in_vino_vomitus, I do not know if you already know this page (I bet many players of DW here know about it) but you can read and learn a ton of useful stuff from here:
http://fas.org/man/dod-101/navy/docs/es310/syllabus.htm

Of course the "U/W ACOUSTICS & SONAR" section is the one of interestest, but if you can spare the time and patience I suggest you to read form the start, "COMMUNICATION SYSTEMS".

Very intresting stuff, worth the time

Thanks! I'll do that thing