According to recently declassified Argentine archives as reported in the 1992 book "Ultramar Sur" by Salinas and De Napoli the following is now known about U-boats arriving in Argentina postwar:
(1) U-530 had been on a special operation to the US East coast after sailing from Germany 19 March 1945. This was three days after the bombing of Dresden and may have been linked to Hitler's orders to fire nerve gas shells at New York in retaliation. Hitler was talked out of this plan by Keitel and Jodl. The order is contained in the OKW War Diary (see also Gellermann: Der Krieg der nicht stattfand). Wehrmuth stated that for his unspecified mission he was under direct orders from Berlin.
The new set of interrogation documents show a conflict between the evidence of the crew members, who described how the 10-5-cm deck gun was jettisoned at sea, and the commander, Wehrmuth, who said that the gun had been unshipped ashore before sailing. This draws attention to the importance of the deck gun. It was Wehrmuth's personal decision to make for Argentina rather than surrender to the USA and for understandable reasons.
(2) There is a duplicate set of documents at the Argentine archive for U-977.
The Brazilian cruiser "Bahia" blew up at the Equator on 4 July 1945 as the result of crew error. At the time it was assumed that a German submarine was responsible, and Schaeffer, whose charts put him within fifty miles of the casualty, seemed a lokely candidate for the noose and the short drop when the US Navy framed him.
There are documentary indications that the Argentine intelligence service conspired with Schaeffer to put him a thousand miles to the north of the tragedy on the day in question, and thus came into existence his novel "U-977" with the world record 66 days by snorkel, all in agonizing detail. The Argentine Navy archive has a different version of the novel as no doubt does ODESSA.
The Kriegsmarine had a naval Etappendienst house at San Antonio Oeste, a small town inshore on the coast of Rio Negro. It seems likely that Schaeffer called in there for orders on or about 18 July 1945, for he was pursued by the torpedo boat "Mendoza" for forty miles and then depth charged there that night. These eight depth charges were the sum total of Argentina's anti-Nazi war effort: their pro-Nazi effort remains their more outstanding contribution. The depth charge attack damaged U-977, but fortunately our hero was saved "because it was getting dark", which resulted in all Argentine naval forces being recalled to base (probably after the Etappendienst got in touch). When Schaeffer put into Mar del Plata on 17 August 1945 U-977 had fresh battle damage up front plus a middling quantity of fuel, which was extraordinary if Schaeffer had come all the way from Norway without seeing man or beast as he claimed.
(3) Two cargo U-boats came down from Germany for which U-977 was the scout. The Etappendienst base could only be contacted by landline, since a wireless transmitter would have betrayed its existence and location, and so Schaeffer went on ahead there for orders. There were three submarines carrying important war material for abroad at the end of the war: U-234 for Japan, and U-235 and U-236 for Argentina. The latter two numbers were duplicates allocated for convenience. According to the Argentine naval archive at least one of these two boats unloaded at San Clemente del Tuyu on the night of 28th July 1945. The police knew all about it and had their work cut out not to get involved. The 1952 depositions to the CEANA enquiry have gone missing, or caught fire or something similar, which has saved everybody a lot of embarrassment. The second boat was damaged during a depth charge attack at the Equator on 18 July 1945 by the Brazilian destroyer "Babitonga" and may have sunk in the Bahia de San Matias while trying to manouevre ashore. There is some evidence that the present Argentine Government believes in the existence of this second boat which has certain material aboard and is so dangerous to approach that it may have been declared a "war grave" by the German Government even though all aboard are believed to have got away safely.
Nothing is known of any other U-boats landing material in Argentina postwar. Local writers, researchers, pilots of private planes occasionally report sunken U-boats and U-boat wreckage and artefacts along the coast, some photographed in lovely colour, but so far nothing of value has materialized and survived scrutiny.