If you are new to U-boat history, I think, with all due respect to Ken, that Ken Dunn\'s impressive description of U-boat radar could be a bit misleading.

Very few U-boats were equipped with radar, and for the most part, their radar detectors were ineffective. U-boats did not go thru the \'radar revolution\' that US boats did, where US boats, universally equipped with high quality SJ radar sets, became heavily dependent on the electronic eyes to the point that it revolutionized their tactics. Sub mounted radar was not a big part of the U-boat world. Some had it, but it was the exception, not the rule.

In the beginning of the war, radar was not on the ocean on either side. U-boats, like surface ships, used only their eyes (with binoculars). This gave the U-boat, with its low siloette, the advantage, even on the surface - night surface attacks became frequent and very effective.

But soon radar sets began to be mounted on allied ships and even aircraft. For a long time the Germans did not know this - suddenly an allied ASW vessel would come pounding out of the mist, priescently knowledgeable of a U-boat\'s location. Also Donitz and the technical staff at headquarters doubted that radars could be mounted on ships, let alone planes. It was not till mid-war that the Germans even admitted that they faced radar equipped foes.

Their initial radar detectors (the Biscay Corss) were incredibly crude and not very effective. Suspicions, possibly fed by English disinformation, made them suspect it eminated signals that allied aircrat homed in on (which was not true) and the Biscay cross was removed from service.

By the time the Germans got a decent 10cm radar detector ready, the allies had switched to 3cm - the Gemrans did not even suspect this change for too long. 3 cm detectors eluded theGermans till the very late war period.

In other words, the Germans spent the war always a step behind, without ever having really good working radar detectors.

As the war dragged on, and U-boats were massacred by radar equipped allied aircraft and ASW vessels, the U-boats gradually spent more and more of their time underwater, with a schnorkel equipped U-boat performing its full patrol submerged. This left them totally blind - no lookouts, no radar, no radar detectors. Just trusting to blind luck that the schnorkel (deployed only about 4 hours a day - the rest of the time was on batteries) would not be spotted. They never knew that the latest allied radar (3 cm sets) could detect schnorkels.

The radar/radar detectors saga of U-boats is a story of almost blind stupidity, and the backwardness of U-boats in this arena was a major element in their defeat