After conducting research, I could not find specific information regarding the boat ramp named US 281 Blanco County in Texas. Blanco County has several rivers and lakes, including the Blanco River and Lake Lyndon B. Johnson, which are popular for boating and fishing. However, without further information, it is impossible to determine which body of water the boat ramp services and what kind of craft are permitted on the water.

It is important to note that boat ramps vary in size and capacity, depending on their location and purpose. Some boat ramps can accommodate large vessels, while others are small and designed for kayaks or canoes. The width of a boat ramp also varies, but most are at least 10 feet wide to allow for easy launching and retrieval of boats.

To ensure accuracy, it is essential to consult official sources, such as local government websites or park and recreation departments, to obtain the latest information on boat ramps in a specific area.