IMHO I would have to say that the yachts from Nautor in Finland make some of the best built boats on the planet! They are truely the Rolls Royce of sailing vessels, without the english "quirkiness" associated with the automobile. As far as a "Production" boat is concerned, the craftsmenship and attention to detail is second to none. If I had to choose a long distance companion for serious and safe offshore work, I would search out one of their 44'' models from the mid 70''s. An S&S design, prior to all the rule cheating goofyness of the IOR era, they are remarkable boats. I have sailed many thousands of blue-water miles on them and they are one of the most honest yachts afloat. I concider the size almost ideal for off shore work. Anything under 40'' seems to get intimidated when the foam is blowing straight off the wave tops.
The Swan 44''s were legendary for their extreme ruggedness. The rig is stout, the hull is massive, and they have all the right stuff for exended stays at sea. They excell in a blow and seem to enjoy it the rougher it gets.
One of their great failings is light air performance. A boat this tough and strong is no ULDB! While no slouch, a more modern design will sail by them in under 5kts of breeze. In addition, the design is a little "close" for work in the tropics, the semi-flush deck has a bare minimum of openings and ventilation could be better.
I was on one in a blow of probably 35kts+, carrying a chute on a dead run, way over canvassed, in steep 15'' waves when the unthinkable happened. Well, unthinkable on most other boats. We stuffed the bow into the backside of a wave, stopped dead in the water, pitch-poled, yet she bounced back like nothing had happened! The total damage? The spin pole track on the mast got a little bent! Amazing! An incedent like that would have dismasted just about any other boat!
Fine examples of these boats still command almost $300k. But there are quite a few in the mid $100k''s. As in any older boat, systems would have to have been kept up and updated. But due to these boats owners fanaticism, most are very well kept.
A Swan 44 would be my choice to cover the globe in security and style!