In the picture you can see one of the local fisherman with his small boat.
The ride from Alleppey to Quilon (or vice versa) by ferry takes around 8 hours. To take the ferry, take a taxi or walk to the decks in Alleppey where the companies have their ships. The ferries are mostly used by locals, but they are also popular among tourists.
Ferries are double decked boats that can carry around 40 or 50 people.