The greatest episode of multinational naval cooperation in the interwar years took place in the early months of the bitter Spanish Civil War of 1936-39.
Frank, Willard C. Jr.
"Multinational Naval Cooperation in the Spanish Civil War, 1936,"
Naval War College Review: Vol. 47
, Article 8.
Available at: https://digital-commons.usnwc.edu/nwc-review/vol47/iss2/8