My dad purchased a wood & canvas canoe maybe 60 years ago and has passed it on to me. The serial number is 29039 18 and he told me that it was an OTCA. It has three thwarts and measures 18 ft in length. In the "Our First Hundred Years" book the OTCA is shown as 17 ft with two thwarts. Is mine truly an OTCA? Is there something special about it that explains the difference in length from that described? I would like to know as much as possible about this beautiful old boat. I've used it off and on all my life.