After conducting research, I was unable to find any specific information about a boat ramp named Duncan in Oklahoma with the provided latitude and longitude coordinates. It is possible that the information provided is inaccurate or outdated.

However, I can provide general information about boat ramps in Oklahoma. Boat ramps in Oklahoma are typically operated and maintained by the Oklahoma Department of Wildlife Conservation (ODWC) and are located on various bodies of water such as lakes, rivers, and reservoirs.

The width and capacity of a boat ramp can vary depending on its location and popularity. Some boat ramps may be suitable for smaller watercraft such as canoes and kayaks, while others may be able to accommodate larger boats and trailers.

The types of watercraft permitted on a body of water can also vary depending on regulations and restrictions enforced by the ODWC or other local authorities. These regulations may include restrictions on boat size, horsepower, and noise levels. It is important for boaters to check the rules and regulations for a specific body of water before launching their watercraft.

In conclusion, while I was unable to provide specific information about the boat ramp named Duncan in Oklahoma, I hope that the general information provided was helpful in understanding the regulations and requirements for boating in Oklahoma.