Bluewater sailing has more to do with the sailor than the boat. Matt Rutherford completed a non stop circumnavigation of the Americas (including the NW passage) in an old beat up Albin Vega 27. Tania Aebi sailed around the world in a Contessa 26, a smaller sister to John Kretschmer's Contessa 31.
Heavy double enders, like the Babas, Hans Christians, Southern Crosses were once thought to be essential for ocean sailing, that's not necessarily the case any more. Steve Dashew pioneered the idea of long skinny fast sailboats to cross oceans, the antithesis of the slow heavy double enders.
While most will immediately talk about hull and sail plan when asked about bluewater boats, that is only one factor. More important factors involve livability at 20° of heel. Take a look at some of newer larger Beneteaus, go below and look for good safe hand holds, where does the cook stand and how safe is it in a bouncing sea? What about the head, too big and there is room to fall and get injured, too small and its cramped and uncomfortable.
Watch the YouTubers sailing around the world and you'll notice they spend far more time at anchor than they do actually sailing. The boat will become your home, it has to feel like home. When we were looking for a boat to cruise on, we considered a Tartan 37, there are many T37s sailing the world and crossing oceans a very capable boat. However, when we look at interiors, they didn't feel like home, too much dark teak. In contrast, when I first stepped aboard a Sabre 362 at a boat show, I felt at home, this was the boat I want and never thought I would own. The 362 is perfectly capable of crossing oceans, several have.
Another consideration is the intended cruising grounds, boats headed for high latitudes have very different requirements than those headed to the tropics.
@jssailem mentioned John Harris website. There is a wealth of information there from John and his readers who are experienced long distance cruisers. Over the past few years he has been involved in the design of an affordable 40' world cruising boat. Those articles are well worth the read. It's a pay site, with a very affordable ~$20 a year subscription, worth every penny.
