Owners of the Cruise Ship Caribe said yesterday they definitely plan to dock in Alexandria next fall despite a decision by the City Council Tuesday night against dredging the Potomac River channel, as the owners had wished.

Alexandria City Manager Douglas Harman yesterday released copies of a telegram he received from Ivo Leon, director of marketing for Commodore Cruise Lines, stating the firm's continued intention to dock the 450-passenger ship in the city this November as a base for Caribbean cruises.

City officials said the telegram was the first official notice they have had that the ship will return to the city for the second year in a row. After last year's sailing, ship officers complained that the Potomac channel was too shallow for safe maneuvering and asked the city to dredge and make docking improvements.

In the telegram to the city, Leon noted the council's decision against dredging and said the decision to go ahead with the Alexandria-based sailings was made after discussion with the ship's captain.

On Tuesday night the council voted $35,000 for dock improvements, but declined to authorize dredging, which would cost as much as $240,000, according to city figures. One reason Harman did not recommend the expensive dreding of the Potomac was that the city expects to receive only $1,100 through lodging and liquor taxes from passengers who stay in the city before the ship leaves.