H27 Speed
I owned a 1979 H27 for about 15 years. This was the deep keel configuration. I almost exclusively sailed with a 150% genny. When the was more than 15 knots, I always reefed the main.The boat will easily sail at 5 to 6 knots to windward in heavy air. Downwind it will surf at higher speeds. I clocked 7 knots many times. In ~10 knots of wind, she would do 4 to 5 knots upwind, but slow significantly downwind. I used a whisker pole on the genny downwind and it really helped increase speed. I also had a cruising spinaker which really helped in light wind. All of these speeds were as measured by the KM (not by GPS).