The atrocity of the Akallabêth

[Raynor]

Such devastation as Tolkien posits could have been avoided by striking while the fleet was at sea, & I'm sure Ulmo could have done serious damage.

Everyone, including Ar-Pharazon, was not sure of the outcome, until they reached the Undying Lands. I would say the good guys were still hoping for a good turn of events at the last moment.

But the fleets of Ar-Pharazon came up out of the deeps of the sea and encompassed Avallone and all the isle of Eressea, and the Eldar mourned, for the light of the setting sun was cut off by the cloud of the Numenoreans. And at last Ar-Pharazon came even to Aman, the Blessed Realm, and the coasts of Valinor; and still all was silent, and doom hung by a thread. For Ar-Pharazon wavered at the end, and almost he turned back. His heart misgave him when he looked upon the soundless shores and saw Taniquetil shining, whiter than snow, colder than death, silent, immutable, terrible as the shadow of the light of Iluvatar.

A beautiful passage...

Manwe only called upon Eru after the numenoreans camped "in might" about Tuna, where from all the Eldar have fled...