Speed isn't the issue, BUT
the mast UP on a sailboat is PART of the calculations for stability. The MOTION of a sailboat without a mast is quite different, less comfortable and quite "snappy," meaning in a seaway the motion is UNcomfortable. I recommend doing some more research before you go this route, like reading some books on sailboat stability. The other thing to consider is that foot for foot, most (I say, most) motor vessels have far more interior space than sailboats. Draft, of course, is an issue based on WHERE you intend to sail. And, motoryachts do "set sail" when they leave the dock.:dance: