The Old Town canoe with serial number 51408 is 17 foot long, AA (top) grade, Otca model with western red cedar planking, open mahogany gunwales, 20 inch decks in mahogany, mahogany thwarts, mahogany seats, a keel, outside stems, a floor rack and a brass bang plate along the full length of the keel. It was built between January, 1918 and April, 1919. The original exterior paint color was black with a gold letter "S" on the black in the right and left sides of the bow and a palm green border stripe with a half inch gold stripe and turned down ends separating the colors. This may have looked similar to the one shown at
http://www.wcha.org/catalogs/old-town/designs/design10.gif which was known as the design number 10. It shipped on April 10th, 1919 to Providence, Rhode Island. A scan of this build record can be found by following the link behind the thumbnail image attached below.
This scan and several hundred thousand others were created with substantial grants from the Wooden Canoe Heritage Association (WCHA) and others. A description of the project to preserve these records is available at
http://www.wcha.org/ot_records/ if you want more details. I hope that you will join or renew your membership to the WCHA so that services like this can continue. See
http://www.wcha.org/wcha/ to learn more about the WCHA and
http://www.wcha.org/join.php to 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.
Benson