Could U-boats still stop a Baltic offensive?

Could German U-boats prevent the Royal Navy from exploiting a decisive victory at Jutland?

Not immediately. Germany would need time to expand its submarine force, while Britain could move quickly with heavy destroyer and light-force protection.

U-boats remain dangerous, but they cannot instantly replace a defeated High Seas Fleet. Germany would need time to build submarines and the infrastructure for a sustained campaign, while Britain could move into the Baltic within weeks or perhaps days. The later convoy commitment had not yet absorbed so many escorts, leaving the Grand Fleet with many destroyers and light forces available for screening, and the shallow coastal Baltic gives submarines less room to hide. Submarines do not immediately cancel British surface superiority. Success would still depend on the extent of German losses and the speed of British action.