One of the three 600-pax. catamarans being built at Astilleros Espanoles in Spain for Atlantic Associates will be operated on day-cruises out of Miami by SeaEscape starting in 1990. The other two will be owned and operated by two other companies in New York and San Diego, according to Joel Rahn, President of Atlantic Associates.

The catamaran design is said to provide greater stability. Naval architect is Jamie Oliver.

The vessels will be 280 feet and have a beam of 75 feet with four decks and a passenger capacity of 600.

There will be no cabins. Instead the space will be used to provide a dining room seating 340, a show lounge seating 335, a full casino, discoteque, theatre, game room, bars and deck area for over 150 lounge chairs.

The three ships will be built at a total cost of approximately $50 million.

Atlantic Associates is one of the principal owners of SeaEscape and operator of the company's onboard casinos.

SeaEscape expects to carry 700,000 passenger this year, up from 630,000 last year.

Joel Rahn would not divulge the identity of the other two companies.

Crown Cruise Line plans to introduce the Crown Diver on exclusive diving cruises from Freeport by mid-August.

The 131-foot, 33-passenger Crown Diver will offer three-, four- and seven-day cruises for certified divers featuring casual and unstructured day-and-night diving. According to Linda Michel Senior Vice President of Sales and Marketing, the vessel will offer all the amenities of a traditional cruise vacation plus the excitement of famous diving spots such as Sugar Wreck, Sherwood Forest and Theo's Wreck.

Sitmar has announced that the first sailing of its new ship, the FairMajesty, originally scheduled for March 14, has been postponed until March 24, due to a delay in construction.

According to Bill Smith, Sitmar's Senior Vice President of Marketing and Sales, the construction delay was caused by a strike at the Chantiers de l'Atlantique yard, which has set back the tightly-scheduled construction program for the new ship.