when word of this threatening thrust reached comdr. william albert parker – who commanded the union naval forces remaining on the james—he dropped his ships downstream to a position where they could maneuver effectively during the expected battle. his vessels experienced great difficulty turning in the narrow, shallow, and meandering channel of the upper river; and "alpha" assisted them to reach their new positions downstream. during the movement, several of parker's warships—including his flagship, the double-turreted monitor "onondaga" – ran aground; and "alpha" proved to be invaluable by helping to refloat them.