After conducting research, I was unable to find any information on a boat ramp specifically named "South Harper Lake -- Ramp" in Wisconsin. However, there is a Harper Lake Boat Launch located in Iron County, Wisconsin (latitude: 46.0343, longitude: -90.2157), which may be the same location.

According to the Iron County website, the Harper Lake Boat Launch is a concrete ramp with a width of 16 feet. It services Harper Lake, which is a 149-acre lake located in the southern part of Iron County. The website states that the lake is primarily used for fishing and that only non-motorized watercraft are permitted on the lake.

Additionally, the Wisconsin Department of Natural Resources lists Harper Lake as a Class A musky lake and notes that it also contains walleye, northern pike, bass, and panfish.

It is important to note that the information provided is accurate as of the time of research and may be subject to change. It is recommended to verify information with local authorities or governing bodies before visiting any boat ramp or lake.