Historical oar design

[frankencrank]

I am wondering if there is a resource that goes to how current oars came to be. Oars are the way that the shell engine transfers power to the water. Efficiency of that transfer is paramount. I see some areas where that might be improved but wonder, first, how we got to where we are, especially in the length of the oar, the location of the oarlock and fulcrum point of the oar. I am not so concerned with the design of the blade.