After conducting research on the boat ramp named 373rd Avenue Southwest McLean County, North Dakota, it has been found that it is a public boat ramp maintained by McLean County. The ramp is concrete and is approximately 20 feet wide. It services Lake Sakakawea, which is a reservoir on the Missouri River. The lake is approximately 178 miles long and covers an area of 368,000 acres. The lake is known for its excellent fishing opportunities and is home to a variety of fish species, including walleye, northern pike, and smallmouth bass.

As for the kind of craft permitted on the water, motorized boats, sailboats, kayaks, and canoes are all allowed on Lake Sakakawea. However, it is important to note that all boats operating on the lake must comply with North Dakota boating laws, including having the appropriate safety equipment on board.

The latitude and longitude provided in the prompt are accurate and can be used to locate the boat ramp on a map. It is recommended to check with local authorities for any updates or changes to regulations regarding the use of the boat ramp and the watercraft allowed on the lake.