Submarines played a minor but interesting role in the supply of Axis forces in North Africa, even before the Regia Marina’s emergency programme of November. Throughout the campaign they delivered fuel, ammunition, and rations. The small amounts of fuel supplied by the submarines were nevertheless valuable. For example, a single run by a Cagni class submarine could supply sufficient aerial fuel to keep the Luftwaffe planes in North Africa flying for one day. Nevertheless, the value of 1kg of supplies landed in Bardia was estimated to equal 6kg of supplies landed in Tripoli, so even the small loads were worth it.
While surface vessels were tested, Bardia was too exposed for a regular service, and too close to Empire airfields. See this older post for an experiment with small steamers at this link. Submarines by comparison had the advantage of stealth, and they were small enough to use the smaller harbours along the coast, such as Derna, thereby reducing the need to spend fuel on forward transport, or to slot into capacity-constrained harbours such as Benghazi with additional supplies. They also consumed far less fuel then destroyers or even cruisers which were also used.
This was not risk-free. Two large Italian submarines were lost on supply missions during CRUSADER, Carraciolo (sunk on 11 December by depth charges from Hunt-class destroyer HMS Farndale after a failed attack on a Tobruk convoy) and Saint Bon (sunk on 5 January by HM/Sub Upholder south of Sicily). Both of them were large ocean-going submarines of the Cagni class.
When Bardia was invested in November 1941 during the early phase of CRUSADER, submarines were used to evacuate officer prisoners of war, such as Brigadier Hargest, commander of 5 New Zealand Brigade, who was captured on 27 November 1941 when his Brigade HQ was overrun, and high-ranking Italian officers or specialist Italian and German personnel who were evacuated to serve again when it became clear that Bardia was a lost cause.
General Rommel at Bardia, 1941, with an Italian submarine in moving in the channel below. Rommelsriposte Collection.
Request for an Overview
On 21 November the German Navy Command (Seekriegsleitung) in Berlin requested from the Commander Naval Transport Italy (Seetransportchef Italien) an overview of German army supplies transported by submarine to North Africa, probably in the context of the ongoing supply crisis due to the interception of the BETA or Duisburg convoy during the night 8/9 November by Malta-based surface units of the Royal Navy.
On 28 November the Seetransportchef responded with an overview that unfortunately does not contain dates, and for most of the missions fails to name the submarine. It is nevertheless of interest.
On 6 February 1942 an update was provided which gave additional information. It is important to note that Italian supplies are not included in these volumes, and neither are those of the Luftwaffe.
The documents are translated below.
Berlin W 35 the 21 November 1941
Fast Memo (Schnellkurzbrief)
For the submarine transports carried out until now a list has to be supplied immediately, including the names, dates of leaving and entering harbor, and the type and volume of goods transported.
High Command of the Navy
Skl Qu.A. Via 10419/41 geh.
Quartermaster Rome 28 November 1941
No. 6466/41 geh.
Referring to the meeting of Oberlt. Vogel and Lt. Kostas, Qu Rom sends the attached list of submarine transports thus far.
1 Attachment The Quartermaster
Supply Runs with Submarines thus far with supply for the Army (starting in May )
Seetransportchef Italien Rome, 6 February 1942
B.Nr. Geh. 841/1942
German Navy Command Italy
Attn. Lt.Commander Stock
Attached we submit an overview of submarine transports during the year 1941.
Total supply since start (10 May 41 to 31 December 41):
1,086 tons fuel
1,072 tons ammunition
203 tons rations
No supplies were shipped in the month of September.
From 20 November to 30 December the following were shipped in 8 voyages:
675 tons fuel
9 tons ammunition
203 tons rations
Italian submarines transported until July only ammunition for the army (about 1,000 tons), from August to end of November fuel and a small volume of ammunition (900 tons fuel and 20 tons ammunition).
During December primarily Italian rations were transported, and at the end of December 4 voyages brought:
139 tons fuel
203 tons rations
for the German Afrikakorps.
Putting Submarine Supplies into Context
To get an overall idea of the volume of submarine supplies compared to other measures, it is useful to look at the files of a single harbour loading unit. In this case the Seetransportstelle Brindisi, reporting on traffic ex-Taranto for the month of December.
Total supply was 12,116.6 tons, in the following categories:
6 motor cycles
1,326 tons for the German army
359.5 tons for the German navy
10,431.1 tons for the German air force
Seven submarines were loaded for a total of 440 tons of army supply. By comparison, the cruiser Cadorna brought 233 tons and 88 men in one voyage, while 6 destroyers brought 49 men and 315.9 tons of supplies.
This article at Regiamarina.net gives a nice overview of Italian transport submarines.
General Rommel and German army and navy officers meeting Italian Submarine officers, Bardia 1941. Rommelsriposte Collection.