You give him the cloak.  He throws it over the fox, then wraps and ties up the fox in it.  (NOTE TO ANIMAL RIGHTS PEOPLE:  the fox is really a guy in a fox suit -- so no animals were abused in this production.  And the fox suit is made of artificial fur.  No letters, okay?) 

He takes the animals across the river, one at a time.  Then he comes back and takes you. 

"I don't understand," you say.  "You couldn't take yourself and more than one small animal at a time over the river on this boat.  But now you're taking yourself and a full-sized human at the same time!" 

"Are you paying for this ride?" the farmer asks. 

"No . . . . " 

When you get to the other side, you ask for your cloak back. 

When you get to the other side, you offer to let him keep the cloak.