One oar in the water

[Will Gilmore]

Note the difference between paddling with a paddle and attempting to "paddle" with an oar. Awkward to say the least.
There are lots of "Monday morning ..." solutions. Even keeping a spare paddle in your rowboat is one.
What can you do if you find yourself in the OP's position? I think he did it.
Next time, however:

-Will (Dragonfly)

 

[Terry Cox]

Once you learn the technique maneuvering a boat with one oar is quite easy and effective. Just think of your dink as a canoe. Done many a solo miles in a canoe.