TRAVEL ON FREIGHTERS
Some transoceanic cargo ships have cabins for a few passengers in addition to those for their crew.
Cargo ships charge less than cruise ships, but they aren’t cheap – around 100 US$ per day, all included. As generally ships can accommodate a maximum of 8/10 guests, they are often fully booked, and may be booked many months in advance.
If you’re thinking of getting a job as part of the crew, forget it! Unskilled crewmembers are not hired on working ocean-going ships.

Freighter World Cruises
Directory by world region of passenger-carrying freighter  services, routes, and price, as well as general information on freighter travel.

Cuises & Freighter Travel Association
Travel Agency specializing in passenger travel on oceangoing freighter ships. Includes a directory of transoceanic and other large freighters that carry paying passengers including routes and approximate trip duration prices.

Check also: www.freightercruises.com and www.freighter-travel.com