What key starts a naval invasion?
Unavailable. No shortcut was verified, so this site deliberately does not invent one.
Safe diagnosis
A checklist for confirming the interface before documenting a naval invasion.
Updated

The checked official description names supply, division design, battle mechanics and a map editor, but it does not document a naval-invasion control sequence. No shortcut, click order or transport rule is published here.
Look for an explicitly labelled naval-invasion, landing, transport or operation control in the current game interface. Capture the full panel, game version and selected country. Do not infer a control from an icon borrowed from another game.
Before testing, record the originating coastline, target coastline or province, selected divisions and whether a front or order line is visibly attached. A map screenshot without the order panel cannot establish that a naval operation was created.
Check whether the UI names an origin port, destination port, transport capacity, convoy or embarkation requirement. These are diagnostic questions only; the current sources do not verify which fields Finest Hour uses or what each condition means.
Record visible supply indicators, unit readiness, order status, battle state and any failure message before retrying. Do not call a failed order a supply issue unless the UI explicitly connects the two.
Until a current recording captures the complete flow, this page must remain a diagnostic checklist. Do not add keyboard shortcuts, exact wait times, port counts or transport formulas. Submit evidence through /sources/ and compare the surrounding systems at /supply-and-encirclements/.

FAQ
Unavailable. No shortcut was verified, so this site deliberately does not invent one.
The checked sources do not document the requirement. Verify the current UI and preserve the exact failure or readiness message before making a claim.