Not sure, since I have been out of it for over a year and a half now, but "Relax" is most probably the original, red-hulled N37, "Semper Fi", that went to Cuba and Bermuda on its own bottom. That boat was sold, painted navy blue, and was renamed "Walkabout". It was sold again, painted dark green, and renamed "All Ours". Based on the mast design, railings, and a few other cues, it looks to have been painted and renamed yet again!
BTW, that question about putting larger engines in and getting 8 knots? Keep in mind that the waterline length of a Great Harbour 37 - like all true displacement hulls defines the top speed and also the ideal cruising speed. Its 56 hp 4JH3 Yanmars will easily push it right up to hull speed (about 8.16 knots, as I recall.) However, the boat and engines are really comfortable at 80% throttle - which (with no current and clean bottom) typically yields a little over 7 knots. Same is true of the later 54hp 4JH4 Yanmars. In fact, some of the early GH37s got 3-cylinder 39hp Yanmars. These boats cruise right along at about the same speed as the 4-cylinders. It can be argued that twin 56hp engines are probably TOO MUCH motor for that hull!
I think you'll find that Ken will counter your suggestion for larger motors with a large dose of real-world knowledge, logic, and facts.
BTW, the longer waterline and 75hp Yanmars in the N47s allow them to cruise comfortably at 8 knots (though most choose to go a little slower.)
ERIC