rowing

For canoes that were originally sold with oars and oar locks, is there any documentation describing the length of the oars that would have typically been sold with the canoe? In my case, I am specifically wondering about an 18-foot square-stern canoe with sponsons...

Got bored with the snow & cold so I refinished this rowing seat & foot brace. It came with a 1906 OT HW project I picked up a few months ago. The seat straddles the rails which measure 12 7/8" wide & 48" long. The seat itself measures 15 1/2" wide & 14 5/8" deep and can be placed anywhere...