Hudson enlisted whitewater man Dock Marston to help pilot the vessel. On their 1948 attempt they crashed in the Lower Canyon and had to retreat. For the 1949 attempt Hudson heeded Marston’s advice, agreeing to make a downriver run first to test the boat and stash gasoline. On June 12, 1949, they left Lee’s Ferry, taking just over five days to complete their downriver run. They refueled at Lake Mead and made another uprun attempt, no more successful than the first. However, their downriver run had made history, being the first time a motorboat had run the river. And although the Esmeralda II never did make it up the Canyon, it spawned an era of hardhulled motorboating through Grand Canyon that lasted into the 1960s with Chris Craft and outboard skiffs skimming through the waves on the high summer flows.
The Esmeralda II, however, had one more remarkable trip. Hudson launched in summer 1950 to repeat his downriver journey, accompanied by Marston in a new Chris Craft. Midway through the trip the Esmeralda II developed engine trouble and crashed. In despair, Hudson cast the boat adrift and helicoptered out. But a week later another river expedition found the Esmeralda II on a cobble bar, pushed it back into the river, repaired the motor and drove it on through the Canyon. Afterward Hudson got in a custody battle with the salvagers which was settled only when the NPS added the boat to their collection, where it resides today.