Propellers from the tug John Purves
4-blade, 76 in. diameter
These two propellers were removed from the John Purves during her renovation in 2007 and wrapped with rope for display.
They were originally installed in 1957 when the vessel was converted from steam to diesel power at the Sturgeon Bay Shipbuilding & Dry Dock Company. They replaced the steam equipment with two 900 hp 12-cylinder General Motors engines and the twin screws seen here.
The pitted condition of the propeller's surface was caused by a phenomenon known as cavitation. This is the formation of vapor bubbles around the spinning propeller. The water pressure is lower than the vapor bubbles, effectively producing a shock wave adversely effecting the propellers' surface.
Location. 44° 49.827′ N, 87° 22.96′ W. Marker is in Sturgeon Bay, Wisconsin, in Door County. Touch for map. Marker and propellers are on the grounds of the Door County Maritime Museum. Marker is at or near this postal address: 120 North Madison Avenue, Sturgeon Bay WI 54235, United States of America. Touch for directions.
Other nearby markers. At least 8 other markers are within walking distance of this marker. Historic Museum Tug John Purves (here, next to this marker); George J. Baudhuin
Also see . . .
1. Tug John Purves at Door County Maritime Museum. (Submitted on October 23, 2015, by William Fischer, Jr. of Scranton, Pennsylvania.)
2. Tug John Purves (Butterfield, USAT LT-145). (Submitted on October 23, 2015, by William Fischer, Jr. of Scranton, Pennsylvania.)
Categories. • Man-Made Features • Waterways & Vessels •
Credits. This page was last revised on June 16, 2016. This page originally submitted on October 23, 2015, by William Fischer, Jr. of Scranton, Pennsylvania. This page has been viewed 160 times since then and 10 times this year. Photos: 1, 2. submitted on October 23, 2015, by William Fischer, Jr. of Scranton, Pennsylvania.