Now you need to make the plastic part of the oar. This will take more detail, so you will be using both extrusion and subdivision to make this transition between parts of the oar:
Zoom out so you can see most of the oar.
Move to the bottom end of the oar. Rotate the view so you can see the bottom of the oar.
Switch to Face Select mode in the 3D View header. Select the face on the bottom with theRMB and press X to delete it. Choose Faces from the pop-up menu, as seen in the left of the following screenshot.
Change to the Front Ortho view. Zoom into the bottom of the oar.
Switch to the Edge Select mode in the 3D View header. Press A to deselect all edges and then select the edges at the bottom of the oar.
Press E and then Enter.
Scale the edges so they spread out to the next major grid line, as shown in the center of the following screenshot. This will be the beginning of the oar blade.
If you think that you goofed up and need to redo...