These sites were not hidden permanent naval yards. A base-defence detachment could arrive with the tankers, erect anti-aircraft and antisubmarine protection, and prepare the anchorage within about a day. The fleet could then refuel and depart while the support ships remained concealed. The distinction matters because mobility and pre-planning substituted for expensive fixed infrastructure.
Notable Point · 1:19:48-1:21:40
Mobile bases were built on arrival
The secret bases were preselected anchorages that tanker and defence detachments could turn into usable refuelling points at short notice.