Actually, the waste of money would be if they spent it on the SS Norway and SS United States for a memorial.
A new or old cruise ship only makes money operating. The SS Norway sailed with 2,000 passengers every week, each spending easily over $500 per person. That's a weekly gross income of at least $1 million per week. As a memorial, to generate that much gross income at $10 per person, they would have to sell 100,000 tickets per week. At $100 per peson, which would probably elimate most visitors as the price would be too high, they would have to sell 10,000 tickets per week.
Of course, an operating ship has far more expenses, fuel, port fees, and crew payrolls. But insurance premiums, financing the loan, paying taxes, and paying port fees, alongside a dock 24 hours/ 7 days a week, will still be there for a stationary ship.
The cruise lines have been very sucessful selling out their ships on a weekly basis. I'm not so sure memorial ships/hotels have been.
I don't believe many will wish to spend a small fortune booking a very small cabin aboard either the SS Norway or SS US on the waterfront, in an industrial area, when there's the Plaza available with much larger rooms located next to Central Park.
The new F3 class passenger capacity is listed at 4200 pasengers. 4200 x $500 = $2.1 Million gross income each week, as a minimum. I can't see how a stationary, old, classic ship can generate that much income, unless it's turned into a casino barge.
Either fix the ships to be cruise ships, sailing the seven seas to exotic ports, or scrap them.