While the Diamond Radisson's maiden voyage is still a year off, the cruise line may already be carving out a unique market niche with reportedly a record number of full-ship charters sold.

According to Keith Wyness, Vice President of Marketing, Radisson Diamond has so far focused exclusively on group and incentive charters. He said that the unusual itinerary rotation of five, five, four, seven- and seven-days, repeating itself every 28 days, allows groups and corporations more flexibility than the usual seven-day program.

Also a unique Radisson Diamond feature, charterers will be able to chose an itinerary among several to be presented for each cruise length by the cruise line. So far, eight different itineraries have been announced. "We will be offering an experience that will be unusual, very special and of very high quality," Wyness emphasized.

Wyness noted that the cruise line works with a 12 to 18 month lead time. "We need the time to sell the cruises," he said, "and the chartering companies need time for promotion to their executives." Wyness said that Radisson Diamond already had sold out several months worth of full ship charters and that charterers include several Fortune 500 companies.

The announced per diem of $600 is far from excessive, according to Wyness, who said that companies frequently spend more than that on hotel rooms alone for their incentive groups.

The meeting and incentive market in the United States alone is estimated at $40 billion in annual sales, i.e., ten times larger than "traditional" cruise sales.

Starting in August, Wyness expects the company also to sell to small groups up to 150 and to individual passengers.

The unique 19,000-ton, 354-passenger, twin hulled Radisson Diamond, which is being built at a cost of $125 at Rauma Yards in Finland, is scheduled for floating out on June 26. It will start sailing in Europe next May 17 (1992) and will spend the first several months in the Mediterranean. In September, she will sail transatlantic from Genoa as the official ship of the Christopher Columbus celebrations.

Starting October 9, the Radisson Diamond will be sailing year-round from San Juan.

A second ship, the Radisson Ruby, has also been ordered and is scheduled for delivery in 1993. The company has an option on a third one as well.

According to test results, the new ship promises to offer several unique qualities including more sea-going stability than traditional vessels and, because the engines are in the submerged pontoons of each hull, less noise and vibrations.

The twin-hull design allows a much wider vessel and consequently better space configuration for staterooms, public rooms and deck space.

The Diamond Radisson is 415 feet long with a width of 105 feet and a draft of 23 to 26 feet. In addition to 354 passengers, it will have a crew of 177. Also on board are two 80-passenger air-conditioned tenders.

Effjohn International, parent company to Commodore Cruise Line, has been contracted to handle marine operations.