Hi Buzz,

Germany did have land-based high frequency direction finding in 1943 however it probably played little or no part in the sinking of the JASPER PARK. She was sunk because the U-boat stumbled upon her at sea. This was the normal way ships sailing independently were found by U-boats. Intelligence reports were used to determine the areas U-boats were sent to patrol though.

There were some incoming radio messages over the course of this patrol about traffic in some general areas that were based on land-based high frequency direction finding and others on reports by other U-boats. Note that land-based high frequency direction finding was pretty inaccurate and might be as much as 200 miles off from the actual transmitter even with triangulation. The Allies deployed shipborne high frequency direction finding on convoy escorts & rescue ships that could accurately detect even very short high frequency ground waves from a U-boat that was within about 30 miles or so from them. Convoy escorts ran right down the bearing and frequently found and attacked a submerging U-boat exactly where they thought it would be. Germany did not have an equivalent.

The U-177’s log book/war diary (abbreviated to KTB in German) for this patrol has been translated into English and is on-line at: [uboatarchive.net]. Start with the entries on page 91 at 12:40 (German time) at grid square JA 3272 (To see this location on a Google map, enter it into the Naval Grid Calculator at: [grid.nylle.de] [click Find your square]) - “Smoke cloud in sight bearing 350°T.”

The deployed Net Defense appears to have made this sinking difficult for the U-boat and resulted in more details in the KTB. Also note that the KTB mentions photos taken through the sky periscope. You might try the U-boot Archiv in Altenbruch Germany to see if they have the photos/video or if they might know where they are.

Hope this helps.

Regards,

Ken Dunn