Hi Bruce,

No, that is entirely different. The infra-red detection theory came about when centimetric radar was first used against the U-boats. From: Miller, David. U-Boats The Illustrated History of The Raiders of The Deep. Dulles, VA: Brassey’s, 2000. ISBN: 1-57488-246-5. Copyright: Brassey’s, 2000.

“In early 1943 it became apparent that, despite the wide-scale use of Metox, U-boats were again being surprised by Allied aircraft and Kriegsmarine technical intelligence staffs sought the reason. At first they thought that the Allies were using some form of supersonic modulation device in the operator's headset. Thus, from March 1943 onwards a device known as a “Magic Eye” was removed from another set in the U-boat (the Telefunken Ela-10.12 “all-wave” receiver) and added to the Metox R.600, to give a visual indication of an incoming signal. It quickly became clear that this was not the answer and the next suggestion (which came from the U-boat men themselves) was that the Allies were using some form of infra-red detection technique. As a result, an infra-red detector was developed and fitted in some U-boats, while others had their upper works painted with an infra-red absorbing paint.- Neither had the slightest effect and Allied air attacks continued.

The next suggestion was that the Metox set itself was producing a detectable signal from its intermediate-frequency stage (ie, it was radiating) and that this was being used as a homing signal by the Allied aircraft. Soon after the Metox entered service the Allies had appreciated that it produced powerful radiations and considered using this phenomenon to home in on U-boats, but their experiments suggested that this was too difficult and the matter was closed. Unaware of this, the Kriegsmarine carried out experiments using a Metox receiver ashore and an aircraft with a suitable detector, which established that the aircraft could detect Metox radiations at 25 nautical miles (46.5km) when flying at a height of 6,560ft (2,000m). This convinced BdU that Metox radiations were to blame and a signal was sent on July 31 1943 stating that Metox was only to be used with great caution, but then, on August 13, a British prisoner-of-war stated under interrogation that-the British were, indeed, homing on Metox radiations and Dönitz issued a second signal which banned the use of the Metox set altogether on August 142 (there is no doubt that a British POW did make such a statement, even though it was totally without foundation, but his reason for doing so has never been established.)”

The coating on U-1105 was actually Alberich an anti-sonar coating. From the same source:

“ALBERICH
One of the responses to Allied sonar was to reduce the U-boats' acoustic signature by the use of a sound-absorbing material to coat the hull. It was hoped this would both contain the U-boats' own noise and also reduce the reflected component of the hostile sonar. This resulted in a system code-named Alberich which consisted of a coating of synthetic rubber (Oppanol) which reduced sounds in 10-18kHz range by an estimated 15 percent (Alberich was the name of a dwarf in one of Wagner’s operas; he made himself invisible by donning a magic coat). It was also believed that the effectiveness varied with changes in temperature and pressure, but these could only be guesses, since the Germans found it very difficult to make comparative tests at sea.

There were two practical difficulties with Alberich. The first was that the Oppanol coating came in sheets 0.2in (4mm) thick, which had to be firmly secured to the hull, but contemporary technology could not produce an effective and durable adhesive. The second problem was that applying the sheets had to be done under cover, and was both time-consuming and labor-intensive.

The first boat to be treated was U-11, a Type IIB, which was employed by the Nachrichtenmittelversuchskommando (NVK = Communications Test Command) for tests in 1940. These were sufficiently promising for an operational Type IXC, U-67, to be treated immediately after launch, but by the time it arrived at Lorient in August 1941 on its first voyage no less than 60 percent of the coating was missing. Indeed, the worst problems arose when the tiles had come loose but had not yet fallen off, since they flapped in the wake and generated eddies, causing more noise than they were concealing and thus totally defeating their object. Further trials were made with one of the captured Dutch boats, UD4, but again difficulties were encountered with the adhesive.

Attention then switched to other means of defeating enemy sonar, mainly by diving deeper. Further work was also done on Alberich and in 1944 several newly completed Type VIICs were given an Alberich coating, using a new adhesive. The first of these, U-480 (Förster), was commissioned in October 1943 and, following the application of Alberich, went to Norway in May 1944 for comparative trials against two other recently completed boats, which lacked the Alberich coating: U-247, a Type VIIC; and U-999, a Type VIIC/41. Following the trials U-480 sailed for Brest, arriving on July 7, having shot down an RCAF Canso (Catalina) en route. U-480 operated in the English Channel in August/September 1944, where it sank a Canadian corvette (HMCS Alberni), a British minesweeper (HMS Loyalty), and a merchantman, (Orminster [5,712t]), and seriously damaged another merchantman (Fort Yale [7,134t]). Following the sinking of the Orminster, U-480 was hunted for seven hours, but managed to escape, a feat for which the captain gave Alberich much of the credit.

U-480 reached Norway on October 4 and left for another patrol in the English Channel on January 6 1945, where it sank another merchantman (Oriskany [1,644t]) and was then subjected to a lengthy hunt. This time Alberich failed to protect it and it was sunk by British ASW ships on February 24 1945 (U-485 and U-486 were also known to have been given an Alberich coating).

Meanwhile, it had been decided that Type XXIIIs and Type XXVIs, then under construction, would receive Alberich coatings, although as far as is known only one Type XXIII, U-4709, was actually completed with the coating, becoming operational in February 1945.”

There was however an anti-radar coating developed but it was only actually used on schnorchel heads. Again from the same source:

“TARNMATTE
Tarnmatte (= camouflage coating) was a compound of synthetic rubber and iron oxide powder which was used to coat schnorchel heads to shield them from Allied radar. It was designed to have its maximum effect at a wavelength of 9.7cm, which corresponded to that used by the ASV Mk III airborne radar carried by British ASW aircraft, and was claimed to absorb 90 percent of such waves.”

Regards,

Ken Dunn