An all-monitor fleet would surrender high-seas control

What if Britain abandoned large seagoing ships after Jutland and built an all-big-gun monitor fleet?

It would cede control of the high seas to Germany because monitors could not perform the battle fleet's oceanic role.

Replacing Britain's battle fleet with big-gun monitors after Jutland would leave the High Seas Fleet able to contest open water. A concentration of heavy guns in monitors would not preserve the seagoing fleet's role. The brief counterfactual therefore turns on what happens when the German fleet leaves harbour. Britain would have given up the force needed to challenge it at sea.