I believe your Andrew was brother to my wife's gggg grandfather Jermiah Knowlton who was captain of schooners Speedwell and Sea Flower sailing out of the Damariscotta River from Nobleboro,Maine. They were born in Ipswich, Massachusetts moving to Damariscotta, Maine about 1776 with their parents Samuel Knowlton and Sarah (Fellows). Where they lived on East Neck Road in Damrascotta became Nobleboro. Look on a road map of Maine and you will find Nobleboro on US Route 1 north of Damrascotta.
In 1997 I visited Nobleboro researching the Knowlton's of Liberty and Nobleboro. I was fortunate to spend several hours with George Dow director of the Nobleboro Historical Society at that time in their library which was an old one room school house. He showed me a lot of information on the Knowlton's. A copy of page 429 from the "Old Bristol and Nobleboro Vol 1, Births and Deaths" he showed me listed Andrew Knowlton born 1752 and son of Samuel and Sarah, married Sarah Ridlon of Newcastle. George showed me a map of Nobleboro dated 1813 which showed Jeremiah owning 100 acres and Andrew owning 81 acres. From his notes on Andrew George mentioned Andrew was a Revolutionary War soldier and mentioined campaigns he participated in. He had six children, John, Joseph, Andrew, Sarah, Susan, and Anna.
George was 92 when I met him in 1997 so he is no doubt not active with the Society today but as mentioned above the Society has much information on the Knowlton's. If you contact them using the infornmation Harlow Chandler has provided I am sure they can be of help. Contact me at email@example.com if you wish to discuss the Nobleboro Knowlton's further.