Cruise lines may be able to increase their onboard revenues, bringing them closer to those earned in hotels, according to Stanley Buchin, senior vice president of Temple, Barker & Sloane, Inc.

According to Sloane, cruise passengers spend $6 a day in the casino, compared to $100 a day spent by visitors to Las Vegas. In addition, cruise lines devote two square feet of gambling space to each passenger, and one slot machine for every 10 passengers, compared to 12 square feet per person and one slot machine per four guests in Las Vegas. Although the discrepancy should not come as a surprise, given the difference in purpose of the two types of vacation, Buchin said there were ways for the cruise lines to narrow the gap.

"Passengers complain that there is not enough diversity in cruise ship casinos, especially in table games. They also claim that the odds on cruise ship slots are not as good as they are in Vegas."

Buchin said the lines might earn more in the casinos if they offered gambling demonstrations early in the cruise, and placed brochures in the cabins explaining how to play the various games.

Other ideas Buchin suggested for increasing revenues included keeping casinos open later; making them more convenient to use by placing them near entertainment and dining rooms; and making it easier for passengers to establish lines of credit.