Welcome and congratulations, the Kennebec with serial number 18878 is a 17 foot long Katahdin model type A as shown on page 167 of volume three in the Kennebec ledgers. It was planked by Mansell on April 24th, 1926. The canvas covering was applied by Tuttle on May 1st, 1926. The first filler coat was applied by Shaw on the same day. Saucier applied the second filler coat on May 8th, 1926. It was railed by Webber on May 15th, 1926 and outside stems were added. The original exterior paint color was blue. It shipped to location number "26-363 384"on May, 22nd 1926. This location is probably an order number but we don't currently have enough information to identify it. The scans of these build records are attached 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 https://www.woodencanoe.org/about to learn more about the WCHA and https://www.woodencanoe.org/shop to donate or join.
It is also possible that you could have another number or manufacturer if this description doesn't match your canoe. Feel free to reply here if you have any other questions.
Ha! Thank you for your comment. My dad cut the ash board on his Wood Mizer mill and used his family's vintage diving board frame. The lake is a deep Kettle lake in PA.