Dennis,
You might want to double check the serial number a little closer. 18187 is a 17' "Charles River" shipped on July 12, 1911 to NYC. I checked 118187 and that was shipped on August 17, 1936 to Maine as a 15' square stern "Paddling" model. I have attached the build records for these to see if anything else matches. If not already a member of the WCHA please consider joining to help support this service along with other services for restoration and knowledge.
Also, check both stems to match up the SN, that may help or post pictures.
Ric Altfather