Welcome, you have found the right place. The Kennebec records are not easy to search and the Maine State Museum is very particular about how this information is to be distributed so there is no direct public access to them. The Kennebec canoe with serial number 13246 is shown on page 211 of volume number two in the Kennebec ledgers. This was assigned to an 18 foot long Kennebec model. It was planked by Roy on October 11th, 1919. He added the canvas covering on October 25th, 1919, the first filler coat on November 1st, 1919, and the second filler coat on January 21st, 1920. The rails were applied by Baxter on February 7th, 1920. The original exterior paint color was medium green. It shipped to Greenfield, Massachusetts on March, 3rd, 1920. The scans of this build record can be found below. These original Kennebec records are reproduced through the courtesy of the Maine State Museum.
The microfilms and scans of these records were created with substantial grants from the Wooden Canoe Heritage Association (WCHA). I hope that you will donate, join or renew your membership to the WCHA so that services like this can continue. See http://www.wcha.org/about-wcha to learn more about the WCHA and https://www.woodencanoe.org/pricing-plans/join to donate or join.
It is also possible that you could have another number or manufacturer if this description doesn't match the canoe. Feel free to reply here if you have any other questions.