In 1886, Dutton led a USGS party to Crater Lake, Oregon. His team carried a half-ton survey boat, the ''Cleetwood'', up the steep mountain slope and lowered it into the lake. From the ''Cleetwood'', Dutton used piano wire with lead weights to measure the depth of the lake at 168 different points. The survey team determined the lake was deep. The currently-accepted maximum depth figure, measured by sonar, is 1,943 feet (592 m).