how to find yacht's owners names

Unless the owner chooses to publicize himself, it's generally not kosher to go around doing it for them.

Boatfool,
Not sure of your background, but let me add my $.02.
Most yacht owners it seems are a private bunch. Some work hard to stay out of the lime light. They work hard, want to play hard, and keep to themselves or close circle of friends/family. Some do like to go public with their yachts and life, and that's fine. But there are some unwritten rules (and written, such as non-disclosures I'm told some crew have to autograph) that we, as forum posters and lurkers, live by. Basically, unless you have permission or it's public knowledge or you have some other cause/reason (and it better be good) to discuss an owner by name, it is not done and many times not tolerated. As someone who works in the industry, I do not like to bite the hand that feeds me, and you never know who is around and watching.
I am curious many times as to yacht owners, what they do, how they got to a position to own a yacht, etc, etc. Many days I'm left wondering, but able to enjoy watching the vessel in which they own cruise by (thanks yacht owner).

Become a yacht broker. Work diligently at it for, oh, twenty years or so.
Knowing the names is kind of like having a baseball card collection: good for bragging rights amongst your peers, but generally not shared with 'civilians'.