Not sure, but it has Wenonah's whitewater layup--center rib with shock absorbers. Possibly one of their downriver ww tandems, perhaps the WW-X. I think the Cruiser would be fairly shallow (12"?). The X was 14-15" deep. I don't have any catalog prior to 1982. Good luck.
Just checked my catalogs. The "Old Cruiser" of the old catalog looks very similar to what you have, and was made in center-rib, but it was 11.5 inches deep and no tumblehome. So depth should tell you.
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