After conducting research, I could not find any information on a boat ramp named "Grave Lake" in Minnesota with the given coordinates. It is possible that the name of the ramp has been changed or that the coordinates are incorrect.

However, there are several other boat ramps in Minnesota that serve various bodies of water. Boat ramps vary in size and shape, depending on the location and intended use. Some ramps are narrow and only allow small watercraft, while others are wider and can accommodate larger boats and trailers.

The body of water that a boat ramp serves can also vary. Minnesota has over 10,000 lakes, so there are many options for boaters. Some popular lakes include Lake Minnetonka, Mille Lacs Lake, and Lake Superior.

The type of watercraft permitted on a particular body of water can depend on various factors, including the size of the lake, the depth of the water, and any rules or regulations in place. Generally, small watercraft like canoes, kayaks, and paddleboards are allowed on most lakes. Larger boats that require a motor may have restrictions, such as horsepower limits or speed limits.

It is important for boaters to check with local authorities or the managing agency for the body of water they wish to access to ensure they are following all rules and regulations.