Patrol vessel A4 () was a small Mersey-class naval trawler operated by Belgium during the Second World War. Originally built for the British Royal Navy, as HMS John Ebbs, the ship is notable for its role in evacuating Belgian gold reserves to England during the Battle of Belgium in May 1940. After the Belgian surrender, the vessel and its crew interned themselves in neutral Spain. In 1946, the vessel and its crew were released and the ship was scrapped soon afterwards.