Based on the latest information available, the Rockland Boat Ramp is a concrete boat ramp located in Tennessee, with coordinates of latitude 36.30017471 and longitude -86.64659119. It is a double-wide ramp, measuring around 60 feet in width, which enables two boats to launch simultaneously. The ramp provides easy access to the Cumberland River, which runs through Nashville, Tennessee, and services the river only.

Regarding the type of watercraft allowed on the river, it is a navigable waterway, meaning that most types of boats are permitted. However, certain restrictions may apply in certain areas, depending on the size and speed of the boat. It is advised to check local regulations before heading out on the water.

In summary, the Rockland Boat Ramp is a concrete double-wide ramp that provides easy access to the Cumberland River in Nashville, Tennessee. It services the river only and is suitable for most types of watercraft.