Sh3.exe and Asdic in shallow waters

[Stiebler]

From October 1944 - May 1945, U-boats with schnorchels patrolled very close to land around the British Isles, relying on the poor detection ability of Asdic in shallow waters, with their fast tides, large rocks and ancient wrecks.

SH3 does not model this failure of asdic in shallow water at all.

I have been looking at the problem, and have now a functioning double-code patch that changes asdic capability according to the depth of the sea. Specifically, the 'minimum surface' (MS) of asdics (original values found in file AI_Sensors.dat') are now changed according to sea-depth in four bands:
Depth > 150m: MS = 100 (m2, metres squared).
Depth >100m: MS = 150
Depth >50m: MS = 200
Depth < 50m: MS = 300.

These changes are not dependent on the year, they will apply throughout the war.

However, for some reason the properties (range, angle, MS, etc) of the asdics are not connected to their names, after loading into SH3. For this reason, I have found it necessary to use a unique value for asdic minimum surfaces, that is, the original value of 100.0 (in NYGM), for identification purposes. But other versions of AI_Sensors.dat use values different from 100.00 (eg GWX, value =0.0).

Therefore I have three queries:
1. Does anyone actually play SH3 around Britain in 1944-1945?
2. Will users be happy to change the minimum surface values of their asdics (only the asdics) to 100.00 in their files data\library\AI_Sensors.dat? It will require manipulation of this data file with a data editor (eg FileAnalyzer, or S3dtor), and the changes cannot be made with a text editor. [Thought: perhaps I could supply these files for stock and GWX as part of the patch-kit.]
3. NYGM has always used the MS=100.00 values, but my other choices of 150, 200 and 300 for decreasing depths are pure guesses. Would anyone be interested in testing this mod, once I have settled the other issues above? It will require a revised SH3Sim.act file, which I can supply, and an extra patch-kit for H.sie's V16A3 patch for SH3.exe.

Otherwise, I shall just keep the mod to myself!

Stiebler.

[reaper7]

Wow Steibler that is amazing. I would definitely be Interested in this for U-Boot_HAHD.
This would suit perfectly the TypeII as they are perfect boats for in the shallow's which we are basing our first Release on.
I'll get Makman94 to talk to on this matter as hes currently looking into sensors for our Mod.


EDIT: Hi Mate sent you a PM on this Would be happy to test

[HW3]

Hum...might make bottoming a u-boat a viable evasion tactic like it was in real life.

[Gerald]

A simple concept, avoid shallow water, where there is the issue of a need....

[Jimbuna]

Originally Posted by HW3

Hum...might make bottoming a u-boat a viable evasion tactic like it was in real life.

Agreed.

[Fish In The Water]

Originally Posted by Stiebler

SH3 does not model this failure of asdic in shallow water at all.

I have been looking at the problem, and have now a functioning double-code patch that changes asdic capability according to the depth of the sea.

Sounds very interesting. Would certainly be a most welcome addition.

[postalbyke]

Could be fun to test... I think I missed parts of it in the technical...
Explain again slowly the meters squared part, please?

I play NYGM so it wouldn't be a stretch...

[ETsd4]

definitely interested.
The meaning of "minimum surface of asdic" is totaly unclear for me.

[complutum]

interested on testing, i'm a GWX user

[Stiebler]

Thanks for the interest, those above.

But no one mentioned 1944-1945, did they? Hmmmm..

'MinimumSurface = 100.0 metres squared':
This means that the asdic must contact 100 square-metres of U-boat hull in order to send a contact-ping back to the transmitting warship. If the value is raised to 300 in very shallow waters, then 300 square-metres of U-boat must be contacted (about 17.5 x 17.5 metres.)

The value in GWX = 0.0. Maybe that explains why no GWX user ever makes it to 1944-1945.

Stiebler.

[jean74]

Hi Stiebler,

If You can realise it, it would be another great improvement ! So far, I think it would make the scapa flow attack more realistic, because when DD detect you in swallow water at long range, it is a realism killing.

Thank you for your work,

Best regards from France,

Jean

[LGN1]

Hi Stiebler,

very good idea! However, I'm reluctant to change any sensor parameter without proper testing and understanding of the relationship between this parameter and the other.

As long as one does not know the real effect of varying the MiniumumSurface value, I think a better solution would be to randomly set the max. height parameter of the ASDIC sensor depending on the water depth. This would be a much better 'controllable' approach.

For instance, for a water depth of less than 50m there is a high chance that max. height of the ASDIC is 60m --> ASDIC will not work in shallow waters most of the time,...


Regards, LGN1

[Fish In The Water]

Originally Posted by Stiebler

The value in GWX = 0.0. Maybe that explains why no GWX user ever makes it to 1944-1945.

No wonder there's nowhere to hide.

Zero meters of hull contact and yet still detected... Well that seems fair.

[HW3]

I've actually made it to the end of the war in GWX but, it sure wasn't easy.

[LGN1]

Originally Posted by Fish In The Water

No wonder there's nowhere to hide.

Zero meters of hull contact and yet still detected... Well that seems fair.

Well, maybe SH3 takes some default value if the variable is set to zero As long as we do not fully know how the value enters the detection algorithm it's useless to speculate about the value of the variable.

Regards, LGN1

PS: Just to give an example. IIRC, in SH4 modders created a visual sensor with a NEGATIVE value for the surface parameter and in this way could create a sensor that could 'see' the submerged sub.