SELECT AVG("Tonnage") FROM table_8360 WHERE "Date" = '18 october 1940' AND "Name of ship" = 'beatus'
What was the average tonnage for Beatus, raided on 18 October 1940?
CREATE TABLE table_8360 (
    "Date" text,
    "Name of ship" text,
    "Nationality" text,
    "Tonnage" real,
    "Fate" text
)