The Phantom Ship is one of the most popular of Crater Lake's many novel objects of beauty. Geologically, the Phantom Ship is a remnant of a projecting promontory of the Lake rim, left by natural erosional forces. It is separated from the mainland by a shallow channel of several hundred feet. As is the case with all earth features produced by the erosive action of water, wind, and ice, the Phantom Ship is doomed eventually to disappear from view.

The lava rocks of this "Ship" are like the others of the Crater Lake region in that they are much fractured by jointing. The joints give ready access to plants, rain, and ice, and promote unequal expansion of the rocks caused by changes of temperature. At the "bow" (southwest) end of the Phantom Ship are several comparatively small spires of rock, succeeded towards the "stern" by the tall pinnacles which rise high above the water, simulating the masts of a sailing ship. On July 25, 1934, between two and four o'clock in the afternoon the second of the smaller spires fell from its place into the lake carrying tons of rock from the side of the "Ship" with it. The evidence of this is shown by the absence of the spire and by a clean gray area of exposed new accumulation of talus at the water's edge. It may have been caused by unequal expansion of the rock during the warm weather of the week of July 25.