Because freighters accommodate so few passengers and the number of ships carrying both cargo and passengers is declining, it can take months -- even years -- to get a cabin on the ship of your choice. So, freighter passengers need time as well as money and a spirit of adventure. And they require accurate information. The following are several organizations and publications which serve freighter travel buffs:

The Freighter Travel Club of America, P. O. Box 12693, Salem, Ore., has 4,000 members who pay $12 a year to receive its newsletter, a clearing house for freighter travel information and tips, and participate in its activities including an annual freighter trip.

Ford's Freighter, Travel Guide, P. O. Box 505, 22151 Clarendon St., Woodland Hills, Calif., with a circulation of 12,000, is a 150-page guide to world-wide freighter travel. Updated editions are published twice a year. Individual copies are $4.95 and both annual editions can be had for $9.

Freighter Advisory Board, 180 South Lake Ave., Suite 336, Pasadena, Calif., 91101, is a biweekly newsletter listing departure dates and itineraries of freighters saidling out of U.S. ports which have space available. Annual subscription rate is $9. It is published by Freighter World Cruises Inc., an agency which represents the principal cargo passenger ships serving the United States.