Merchant depot ships for Polish submarines

One proposal is to modify merchant, whaling-factory, or fish-factory ships as covert submarine depots. First World War Q-ships provide a precedent for vessels whose commercial appearance concealed a naval role, although these auxiliaries would support Polish submarines rather than hunt them. Their plausible trade could let them wait in neutral island or Scandinavian ports within reach of Polish boats. Submarines could receive sealed wartime orders directing them to attack German targets and then signal at a prearranged rendezvous for fuel or supplies. The scheme would be difficult diplomatically and operationally, but it directly addresses Poland's lack of secure bases without pretending that Baltic geography can be changed.