Basing capital ships at Heligoland would make them vulnerable to surprise attack without adding much the Royal Navy cannot provide from larger bases. The island also lacks the harbour and support capacity needed to sustain a battle squadron. Its limited space is better used by light forces that can patrol, lay mines, and complicate a German approach. Battleships can then remain at safer, larger bases until the fortress reports that the German fleet has committed itself.
Notable Point · 1:56:48-1:57:43
Why Heligoland would not host a British battle squadron
The island lacks the harbour capacity for a battle squadron, so its naval role would centre on destroyers, torpedo boats, submarines, and fortress guns.