As regards your use of the word, 'correctly', R1G, in an American context the endeavor form - without the 'u' - WOULD be perfectly correct, were it not for the apparent association with the British vessel.
The word first entered English as endower in the 1400s and, after many other variant spellings, did not settle down as endeavour here until over two centuries later. Of course, by then, the Pilgrim Fathers had already left for America, taking with them whatever ideas they had about spelling!
American English is different...not wrong!