2 replies to this topic

[Raymond Runge]

The U-boat data for a type VII and IX have a + under sonar yet the CRT does not have a + on the Kriegsmarine Acoustic Chart, which is right.

[Lonnie Gill]

Good question Willkiller, The Kriegsmarine ACOUSTIC table on chart 5 D (Amendment 1) is used for active sonar used by surface ships for ASW. The less effective German sets get only S = and S - ratings, which are used for attempting to detect submerged Allied submarines.By contrast, German passive acoustic sensors (hydrophones) were excellent. The Gruppenhorchgerat (GHG) fixed hydrophone array installed on U boats was able to detect a single ship nearly 11 miles away and convoys at even greater distances. A claim has also been made that Prinz Eugen detected HMS Hood while she was still beyond the horizon using the surface ship equivalent. This capacity was very useful for U boats detecting general convoy and target locations, but not sufficiently precise for U boat or surface escort ASW point attacks on submerged subs.I used a S + rating on the U boat Ship Log for this excellent passive sensor. I should have listed it as a hydrophone (passive) rather than a sonar (active) sensor. [U boats also had active sonar (S -) but seldom used it due to the risk of detection by Allied sensors.] The capacity of this passive sensor is reflected in rule Section 3.5.8 on page 3-5, which provides it can detect a convoy or task force of five or more ships at ten times the S - range listed on the ACOUSTIC table. It is also subsumed in the German section of the SUBMARINE CONTACT table used for campaign submarine operations.I will try and make this clearer in future updates to the submarine Ship Logs. An optional rule may also be in order to more clearly reflect the Kriegsmarine superiority in passive acoustic detection.LONNIE

[Raymond Runge]

Thanks, Lonnie