Maymun bin Mihran narrates from Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him), when his Companions were setting out for Abyssinia, ordered them: "Pray standing in the boat as long as there is no fear of drowning."
Thus he narrated it; there is disagreement about it over Abdullah bin Dawud, and it is said that he did not hear it from Ja'far. The hadith of Abu Nu'aym al-Fadl bin Dukayn is hasan (good).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5490