I read the book Kretschmer, in which the author Lawrence Patterson quoted one of Dönitz's report concerning the collaboration with the Italian submarine service. One element given for the bad performance of Italian submarines is that:
Italian submarines had never sailed in such waters and meteorologic conditions. They are not adequately equipped for that.
I would like to know more about the necessary equipment that the Italians were lacking?
The Italian submarines originally suffered from two material issues that prevented them from operating efficiently against convoys crossing the North Atlantic. The following quotations can be found on page 147 of the English translation of Karl Dönitz's memoirs "Zehn Jahre und zwanzig Tage":
In the Italian submarines the conning-tower was very long and very high. Both by day and by night it offered a very conspicuous
silhouette. The lookout's position was far below the top of the very
high tower with its long periscope mountings.
Further these Italian submarines had no Diesel air supply mast in the conning-tower. This meant that when running on the surface, the
conning-tower hatch had always to be left open in order to ensure for
the Diesels the requisite supply of air for combustion purposes.
These were significant issues. Why? In the North Atlantic, the Germans sought to apply the "wolf-pack" tactic. Submarines sought out and maintained contact with convoys until a sufficient number of submarines could be assembled. Then they attacked en masse on the surface during the night. A small silhouette was a necessary condition for the success of this tactic. In the North Atlantic, the sea is typically so rough that it is impossible to keep the hatch in the conning tower open for any period of time.
These material problems were quickly rectified. After the fall of France a base was established for the Italian submarines at Bordeaux. Here the conning towers were both shortened and reduced in overall size and they were fitted with an air supply line for the diesel engines. Dönitz implies that the refits were completed by the end of November 1940.
Moreover, there were significant differences in the how the Germans and the Italians trained their crews and deployed their submarines. These issues are important in order to understand the failure of the Italians in the North Atlantic and their successes in the middle and South Atlantic. However, this topic is outside the scope of the original question.
Karl Dönitz : "Ten Years and Twenty Days". Da Capo Press, New York 1997
Italian submarines and their adventures in the Atlantic during World War II, there were a few key pieces of equipment that they were lacking. One significant factor was the absence of an efficient air conditioning system aboard their submarines. The scorching temperatures of the Atlantic waters made it challenging for the crews to endure long patrols without proper climate control, leading to discomfort and fatigue.
Additionally, Italian submarines often suffered from inadequate sonar systems, which affected their ability to detect and track enemy ships effectively. This technological disadvantage put them at a significant disadvantage in the cat-and-mouse game of submarine warfare, as their detection capabilities were inferior compared to those of their Allied counterparts.
Furthermore, Italian submarines faced limitations in terms of long-range fuel capacity. The Atlantic Ocean presented vast distances to cover, and the Italian subs struggled to maintain extended patrols due to their limited fuel storage. This constraint restricted their ability to remain at sea for prolonged periods, reducing their effectiveness in conducting operations in the Atlantic theater.
However, it's worth noting that despite these equipment shortcomings, Italian submarines did achieve some successes during their Atlantic campaigns. They managed to sink a number of Allied vessels and occasionally proved to be formidable adversaries. Nevertheless, these deficiencies in air conditioning, sonar systems, and long-range fuel capacity undoubtedly impacted the overall performance and capabilities of the Italian submarine fleet in the Atlantic theater during World War II.