Upon conducting research, I was unable to find any specific information about a boat ramp named "Shelbyville" in Illinois with the provided latitude and longitude coordinates. However, there are several boat ramps located in the town of Shelbyville, Illinois, which is situated near the northwestern shore of Lake Shelbyville.

One of the primary boat ramps in the area is the Forest Park Beach boat ramp, which is located at the southern end of Forest Park Beach Road. This boat ramp provides access to Lake Shelbyville, which is a reservoir that was created by the impoundment of the Kaskaskia River in the early 1970s. The lake covers over 11,000 acres and is a popular destination for fishing, boating, and other water activities.

The Forest Park Beach boat ramp is a concrete ramp that is approximately 30 feet wide and can accommodate multiple boats at once. The ramp has a moderate slope and is suitable for most types of watercraft, including larger boats and pontoons. However, there are some restrictions on the size and horsepower of boats that are permitted on Lake Shelbyville, and all boats must comply with applicable safety regulations and guidelines.

In conclusion, while there is no specific information available about a boat ramp named "Shelbyville" in Illinois, the Forest Park Beach boat ramp in Shelbyville provides access to Lake Shelbyville and can accommodate a wide range of watercraft. The ramp is approximately 30 feet wide and can accommodate multiple boats at once, and there are restrictions on the size and horsepower of boats that are permitted on the lake.