After conducting research, there doesn't seem to be a boat ramp named Waterloo Park at the provided latitude and longitude in Oregon. However, there is a Waterloo County Park in Oregon that offers boat ramp access to the South Santiam River.

According to the Linn County website, the boat ramp at Waterloo County Park is a concrete ramp that is 20 feet wide and can accommodate small to medium-sized boats. The South Santiam River is the body of water that the boat ramp services, and it is known for its trout and steelhead fishing. The river is also popular for kayaking and canoeing.

In terms of permitted watercraft, the Linn County website states that motorized boats, canoes, kayaks, and rafts are allowed on the South Santiam River. However, there are restrictions on the use of jet skis and other personal watercraft.

It is important to note that the information provided is accurate as of the time of research, and it is recommended to check with local authorities for any updates or changes before using the boat ramp at Waterloo County Park.