Time for action — making the blade
Now it's time to make the oar blade itself. The modeling will be a little more complex, so pay close attention to the steps:
Zoom out a little and move the bottom of the oar to the top of the 3D View. Move the mouse to the top of the 3D View. Have at least eight grids below the bottom of the oar.
Press E, and move the new edges down 0.8 units, eight of the grid sections. PressMMB after starting your motion to restrict the motion to Z. Use the Ctrl key while moving the edges for more precision.
Zoom in to the bottom of the oar. Choose the Vertex select mode. Press A to deselect all vertices. PressRMB to select the left vertex, and then Shift+RMB to select the right vertex on the sides at the bottom as seen in the following screenshot:
You don't need to rotate the view, but after selecting the vertices, zoom back out so you can see three or more large grid lines on either side.
Press S, X, and use the mouse to scale them in X. Scale them out by one and a half...