The U-boats did use hydrophone based speed evaluation

sublynx · 08-30-13, 06:44 PM

Ever since Raduz's Hydrophone hunting tutorial there's been controversy among us reality buffs about whether the Germans used hydrophone for assessing ship speeds.

Well... Have a look at these pics I took from U-552's 6th war patrol KTB:

Topp's description: "200 RPM = 20 knots"

The torpedo firing report

To me this looks clear. Topp was submerged, the hydrophone operator counted the 4-stacked destroyer's engine revolutions per minute and Topp estimated that 200 RPM corresponded to a speed of 20 knots.

I haven't seen this in other war diaries I've read, so I believe hydrophone speed estimating was a rare occurrence. But I also believe that estimating the speed of ship by a hydrophone was not something that Topp just invented then and there. If he had, he had written more about it - now it looks just like a standard practice that needs no explanations whatsoever. Just the "200 RPM = 20 knots".

Here's the link to the war diary:

http://www.uboatarchive.net/KTB552-6.htm

Anyone interested in giving back to the SH3 community? There would be a need for someone to make the RPM / speed charts for the Warships in SH3. The charts for merchants have already been done for GWX and NYGM by Canovaro and CapSea - now we would need to get the info for those pesky Black Swans and Flower corvettes etc

08-30-13, 06:44 PM	#1
sublynx Sea Lord Join Date: Mar 2011 Location: In the conning tower of my VIIC scanning the sea through the periscope Posts: 1,698 Downloads: 173 Uploads: 7	The U-boats did use hydrophone based speed evaluation Ever since Raduz's Hydrophone hunting tutorial there's been controversy among us reality buffs about whether the Germans used hydrophone for assessing ship speeds. Well... Have a look at these pics I took from U-552's 6th war patrol KTB: Topp's description: "200 RPM = 20 knots" The torpedo firing report To me this looks clear. Topp was submerged, the hydrophone operator counted the 4-stacked destroyer's engine revolutions per minute and Topp estimated that 200 RPM corresponded to a speed of 20 knots. I haven't seen this in other war diaries I've read, so I believe hydrophone speed estimating was a rare occurrence. But I also believe that estimating the speed of ship by a hydrophone was not something that Topp just invented then and there. If he had, he had written more about it - now it looks just like a standard practice that needs no explanations whatsoever. Just the "200 RPM = 20 knots". Here's the link to the war diary: http://www.uboatarchive.net/KTB552-6.htm Anyone interested in giving back to the SH3 community? There would be a need for someone to make the RPM / speed charts for the Warships in SH3. The charts for merchants have already been done for GWX and NYGM by Canovaro and CapSea - now we would need to get the info for those pesky Black Swans and Flower corvettes etc