The Mirabella V is $300,000 per week, can comfortably sleep sixteen plus crew and can absolutely fly.
"Mirabella V now has official certification from Guinness World Records for the tallest mast and largest sail."
I think that this section from Jackart's post makes a surprisingly large point:
"Now Johnny socialist looks at that and thinks "how many hospital beds could be bought with that". or "That could have been spent on the poor/schools/welfare/Nurses [delete as applicable]"
That attitude totally misses the point of being human - where would we be if the Chairman of Avis car rental wasn't able to think "I know. I think I want a boat with a 300ft mast" and then go to the company who makes the Royal Navy's warships and say "Make me a bloody big boat, with sails as big as a footaball field"
Capitalism enables people to make beautiful, magnificent, pointless things like Aston Martins, Ducatis, and the Mirabella V. I may never own one (or any other yacht). I may never even Hire it for a week. But I am glad it exists, and if I see it passing me in a shipping lane I will wave and smile. The people on board will ignore me and turn smugly to their pink gins. I don't care."
It may be possible for someone like Rawls to accept this boat's existence as the cost to the poor of destroying the market mechanism's that allow it may be larger than the benefit to them of redistributing the wealth that allows for it or limiting people's consumption choices. However, the boat cannot be celebrated by anyone, like Rawls, who judges the worthiness of an action primarily by a difference it may make to the fortunes of the worst off in society; it is clearly a collosal waste in that regard.
This is similar to the conundrum which has exercised Nietzsche and several other major thinkers; that art is cruelty. Art as art is necessarily pointless in practical terms. While some art may at times fulfill useful functions this is usually where it overlaps with design or is being used as a tool to communicate some political or practical message. Art itself as the expression of emotions or the creation of something beautiful is profoundly and wonderfully useless. In a more concrete sense most art will have little to no contact with the poor and the idea that its effect will pay its way through some kind of trickle down is rather poorly substantiated.
Think about it this way. While someone, somewhere is starving to death another person is sitting in comfort with the capacity to help them and is instead choosing to paint something that will wind up in a gallery being appreciated by others who are well off. Awful.
The answer is that although art, and collosal luxury yachts, are both cruelties they are both also clearly wonderful. Once you realise this it becomes necessary to rethink an awful lot of morality which cannot make room for wonderful things.