It was suggested of me, to write to Good Old Boat magazine...which I did.
Here's the reply:
Hi Rich,
I'm stumped.
C&C (standing for Cuthbertson & Cassian), an Ontario, Canada boat builder designed and built a Viking 28' in 1968 and a Viking 33' in 1971 and then a redesign in 1973 (then calling it a Viking 34'). I only know this because one of their designers is my technical editor, Rob Mazza, and we've reviewed and published this boat in Good Old Boat Magazine, issue #116 Sep/Oct 2017. But a quick search on Wikipedia will also give you this basic information. And you are correct, they did not design the one you are inquiring about. In fact, the insignia for the Viking 28 & 33/34 is a large V, certainly not that distinguishable viking head in the picture you provided.
The only other sailboat designer that I could think of that is viking-like is the Ericson which uses a viking helmet as their insignia. They started building sailboats in 1969, starting with a Bruce King design of the Ericson 23' sailboat.
I tried a few searches online to try to locate your particular boat, but came up with no result. I also shared your email with Bob Muggleston, my editor. He was intrigued by the insignia but admitted he'd never seen it, and he too reported that a quick online search resulted in zero results.
If you don't mind, I'd like to put this on our Facebook page and see if our readers/audience can help identify her.
Cheers,
Karla Sandness, CEO, CFO, Publisher
Good Old Boat Magazine