THOMAS:

You wrote: "..........the first successful testss of a submarine-based
launch platform for a rocket were from German U-boats in WWII
using a towed launch platform. These specially designed rockets were developed to be launched out of a submarine and after several test launches the German program was stopped."

"In the summer od 1944, three U-boats of the Black Sea 30th flotilla were secretly equipped with rocket launchers, These were mounted amidships below the waterline of U-24 and U-9 and on
the deck of U-19. The weapons were allegedly deployed against Soviet harbor facilities and moored sships during the German
retreat. Although the records do not mention damage sustained in
the attacks, this first combat use of a submarine-launcched missile was an historic event."

"To overcome the transcontinental barrier that pevented Germany
from atacking tthe U.S, at home, an official of the German Labor
Front, Direktor Lafferenz, suggested that a watertight container be constructed, in which a V-2 ballistic missile could be brought
within range of the American coast. Discussion of this novel idea reached the highest levels of the Penemunde research faclity. As
it developed, the plan was to send three 500-ton displacement
containers towed by a single snorkel-equipped submarine. Each
container, trimmed to neutral buoyancy, concealed a V-2. Upon reaching the start location, the containers would be trimmed to a vertical position, and the rockets launched."

"The idea was filed away until 1944, when it was given the code name PRUFSTAND XII and Vulkanwerft secretly began work on three containers. While the records indicate that at least one such submarine launch container was completed, it was never tested with a live firing."

Do you have another source that refutes this information?

Regards,

ROBERT M.