Would HMHS Britannic have survived if her lower-deck portholes had been closed?
Short answerPossibly; slower flooding could allow grounding, after which surveyors and the government would decide whether to rebuild her.
NotesOpen lower-deck portholes admitted water as Britannic settled, compounding the mine damage faster than the ship's protections could contain it. With the openings secured, the captain might have reached shallow water and grounded the vessel while bringing lifeboats closer to shore. Lloyd's Register or another assessor would then determine whether the damaged forward hull and machinery spaces were economically salvageable. Because the ship was valuable and under government charter, temporary repairs near the Mediterranean followed by reconstruction at Harland and Wolff would be plausible if the structure survived grounding.