With Captain Edward Ellison in command, the Rosinco departed Milwaukee harbor late Tuesday evening. The five-man crew consisted of Harry Marumrud (chief engineer), G. L. Beatty (steward), John Larson (lookout), and able seamen W. H. Cerben and Lars Rorick.

Ten miles off Kenosha at 2:45 a.m. on Wednesday, 19 September, the vessel reportedly struck a raft of sawed wooden beams, or "box timber," that apparently ruptured the steel hull. The duty crew quickly awakened those who were sleeping below decks and everyone hurried topside. Within minutes it was plainly evident that Rosinco had been mortally damaged and was sinking rapidly.

The Rosinco is located approximately 12 miles east of Kenosha at N 42º 37.30', W 87º 37.74'.

Everyone promptly jumped ship and swam to the small motor launch towed behind the yacht in tandem with a tiny rowboat. No sooner had the crew and their guest cast off the line that tethered the launch to the Rosinco than the yacht's stern lifted into the air and the grand vessel slid, bow first, beneath 185 feet of water. Only one casualty was incurred: the ship's canary mascot.