By the time they reached the water, in fact, well before that, one engine had gone to zero thrust (right), and the left had slowly died from idle thrust to zero by 1000'. Sully set mid-range flaps (15 degrees if I remember right), and never got around to the 'infamous' 'ditch switch'.
Would have been moot, as the water contact ripped open the fuselage aft anyway.
Not a source I usually trust, but Vanity Fair magazine had a first person interview and his recollection of the events. He also praised all of his crew, especially the F/O for professionalism under fire.