In Leningrad, Russia the Soviet Naval Staff issued orders directing the fleet and shipyards to concentrate their efforts towards overhauling and repairing Soviet submarines (some of which were being employed as power-station generators for the besieged city) in order to prepare for a spring offensive in the Baltic Sea. Submarine crews and other specialists were recalled from the front (where many were fighting ashore) to assist in the preparation of some thirty submarines for the campaign. In Apr 1942 the submarines would be divided up into three groups by Brigade Commander A. M. Stetsenko according to their sea fitness. The first group, consisting of the most experienced Captains, such as Y. P. Afanasev, S. P. Lisin, and G. Ya. Osopov, was expected to have ten submarines ready to sail by the end of May 1942 with another seven nearing completion of their overhauls; the second group was scheduled to be ready by Aug 1942 and the third by the autumn.