Originally Posted by slap
If you assume a boat speed of 6 knots, you are traveling 1 nautical mile every 10 minutes. If it takes another boat 10 minutes + 80 seconds, they are traveling at around 5.3 knots.
You are correct - was over simplifying the morning after a few too many drinks the night before. Oops . Just to clarify a little more and make it real. Assume a 50 mile day, that means the Tayana would take about 80 more seconds per mile or 1.3 minutes per mile more x 50 miles which is just over an hour longer. That kind of time over distance can really add up on a passage. Now recognize that PHRF assumes a windward/leeward race course, this does not account specifically for boat speed but rather is a handicap system to account for speed, acceleration etc.
So for cruising, what you really care about is average boat speed [think waterline length] and comfort [think displacement vs length and hull shape]. The more modern hull designs allow for faster passages which offer certain advantages.