Re: A bluewater live-aboard for under $20k
When you actually get around to shopping for this dream boat, you may find that your options are a bit limited. You will only be able to shop in a certain geographic area, for a boat that is in reasonable shape, but not too expensive, etc. It will help a lot if you have a fair number of boats you would consider (and learn why some others wouldn't be such a good idea).
Find a cheap(ish) boat. Just keep it coastal, and pick your weather windows. Save the ocean crossings for another boat.