You coudl start with the stuck list at the top of this forum. That is the mahina boat list. Be it a good list or bad is another story. WHat is blue water for me, would be different if I was doing this with spouse and twin sons and 2 daughters too.
Blue water can mean a Jeanneau Sun Fast 3200, Beneteau Figaro, or a mini transat. I should point out, these three are designed for SH or DH ocean racing.
A local just went from here in the Pacific NW to Oz and back in a Jeanneau 49iP. A brand that does not seem to get onto many BW list. 2 couples I know of have taken there Hunters from here to mexico and back. One 4 times, granted the last one or two by truck, but initially when younger, there 78 38' cutter when down and back on its hull. again, another brand that most would not put in a BW category.
You will find there will be trade offs which ea kind of boat you look at, then you can decide if the tradeoffs are worth it or not. Me personally, the list of boat in the Mahina list not one would I choose, while a good list, not sure I like the lack of speed for many on the list. ANY boat properly built, outfitted etc, should be able to go offshore if in the size you are looking at, ie 37-45'. If not, then it was not designed to do so.
She drives me boat,
I drives me dinghy!