[2026.1]Realistic Hydrophone

Many people reported the AI hydrophone operator as not being able to identify nearby ships when using this mod. Even when they are clearly audible when manually listening. After extensive testing, this seems to have been caused by the vanilla game heavily penalizing the AI hydrophone range due to weather.

• This new update overhauls the influence of weather on hydrophone range to realistic levels. Specifically, the hydrophone range penalty is now an exponential, instead of linear function of Sea State. The AI hydrophone operator should now be able to identify ships at the realistic ranges mentioned below– even when the Sea State is mild. The hydrophone range will remain minimized in particularly heavy Sea States, although it will not be the previously unrealistic 100% penalty.
• The depth of the U-boat will now influence the effect of Sea State on the hydrophone range. Dive 50m below the surface to minimize the effects of Sea State as much as possible.
• Text has also been added to the Horchraum tooltip to indicate the % reduction in range that results from the current Sea State and depth.

This mod gives the hydrophones realistic ranges.
It will be much harder to obtain your Tonnage totals!

Using the first GHG (Gruppenhorchgerät), you can expect to find lone merchant ships between 16-19km away, given that you have an additional sailor in the Horchraum.
Medium-sized (~10 ships) convoys can be found at around 32km.

Using the GHG-Balkon upgrade, the ranges are extended to resp. about 22-27km and 45km.

The KDB upgrade is interpreted as including the standard (although slightly modernized) GHG, so gives a modest increase in range of 10%.

Very careful manual listening will allow you to hear targets about 1-2km further than the AI technician officer.

Requires a new save game!

The mod is compatible with GHG 360.

It is not compatible with any mod that makes changes to the hydrophone entries in Entities.xlsx/Equipment, or to a few of the /Detection Settings in General.xlsx.

Not compatible with:

• Surface GHG (1.0 FULL RELEASE COMPATIBLE)
  (The changes it makes are incorporated into my mod however!)
• Kriegsmarine Aces v1.2.2 (Full Release Compatible)
  (Unless you overwrite it with my mod.)
• [2024.1] Career Campaign and Character Progression
  (If you want to use both, I recommend copying over the ‘Parameters’ values from my Entities.xlsx datasheet.)
• Harder Better Faster Darker

"The maximum range at which a destroyer or small merchantman can be heard under good Atlantic condition is said to be 10 miles and convoys may be heard up to 20 miles."[www.uboatarchive.net]

“It was stated that G.H.G. enabled U-Boats to hear ships which were below the horizon, estimated at a distance of 12 miles […]|”[www.uboatarchive.net]

"The Allies probably did not realize how efficient the German listening equipment was until the summer of 1941 when the U-570 was captured by the British. They then discovered that German […] listening was possible up to ranges of ten miles under good water conditions.The normal range of the U-boat GHG was said to be 20 kilometers with the U-boat running submerged at 3 or 4 knots; this range fell to 3 to 5 kilometers at 15 knots.[pubs.aip.org]
From: Holt, L. E. (1947). The German use of sonic listening. The Journal of the Acoustical Society of America, 19(4), 678-681.