You don't really have to live on the boat... that is if you hav an appartment.
EK has no business with where you invest the money in, but of course, you have to live somewhere since you won't be entitled to EK accommodation anymore, and that is for the rest of your career with EK.
Personally I can't see one living on a boat in DXB on a permanent basis because of the heat. Also, you need a place to wash your clothes, what about telephone and internet etc...
Having said that, a few guys do live on a boat in DXB, but as far as I know, they commute most of the time and live on the boat when they are in DXB.
MR8