Based on my research, the Cooper Avenue 56 boat ramp in Cleves, Ohio is a public boat ramp that provides access to the Ohio River. The ramp is said to be about 20 feet wide, which should accommodate most boats. However, I couldn't find an official source to verify this width.

As for the type of watercraft allowed, it appears that all types of boats are permitted on the Ohio River, including powerboats, sailboats, canoes, and kayaks. However, there may be restrictions based on seasonal conditions or local regulations, so boaters should check with the relevant authorities before launching their boats.

Overall, the Cooper Avenue 56 boat ramp appears to be a relatively small and basic facility, but it should provide adequate access to the Ohio River for local boaters. As with any boat ramp, it's important for users to follow proper safety and etiquette protocols, including being respectful of other boaters and maintaining compliance with all applicable laws and regulations.