There's no question, the NS 27 is an extremely capable little boat. But I find it hard to believe that a boat originally designed and marketed to be trailerable, would have been the choice of more circumnavigators than any other boat out there...
I've never seen a definitive answer to the question, and I doubt anyone knows with any certainty, but if I had to put my finger on one boat that has gone around more than any other, I'd guess the Tayana 37... They had a very long production run, many are available at good prices, and have long seemed to me to be a very popular choice among those taking off for extended cruising. Or, perhaps the Valiant 40, or Westsail 32... Among boats under 30', I'd guess maybe the Albin Vega, or Contessa 26?
Jon don't take me wrong but I find funny that when Americans talk about the boat that has made more circumnavigations they always talk about American boats. Sailing is a lot more popular in Europe and there are a lot more sailors in Europe. Do you think that French, Germans, British, Dutch, Swedish, Danes Spanish or even Portuguese when circumnavigate they do that in American boats?
More, on the last 10 years probably were made more circumnavigations than on all decades but together. Do you think that on the last 10 years the Tayanas or Vaillants were the boats more used, even by Americans?
I don't know and certainly they are not the boats more suited for it but if I would bet on a brand I would say Beneteau, Bavaria or Jeanneau, just because they are the boats that have been made in great number and the ones you can find in Europe and in the States.