Robi, what you are asking is the very essence of downwind speed itself. Only the Master knows for sure, which will be faster in a given wind condition and on a given course. We mortals can first start with the two extremes: light air (5kts) and heavy air (20 kts). Obviously in light air you cannot trap, so you sit way inboard and try to get the hull up to minimize drag. Heat it up, lift the hull, slowly bear away while trying to keep it up, rinse and repeat until it's time to gybe. In heavy air you must trap or swim, but you will still want the hull up for less drag, as long as it won't lead to swimming.

So the "change over" point is the great unknown and that is where experience and skill come into play. If we go half way between 5 and 20, that is 12.5 knots of wind. So about there you will need to chose one. Having the experience to know which one to choose is what makes fast guys fast. But the wind is never that steady. What is fast right now might not be fast when a puff hits or when you sail into a hole. You have to shift gears a lot when it's gusty and the fast guys are the ones who are very good at shifting gears quickly.

I have crawled up the mountain to ask the Master and he told me this: "Speed is the only thing that matters, so make it go as fast as you can, as long as you can."

And remember, gaining speed will move the apparant wind forward, thus allowing you to go deeper, and at greater speed, until it bleeds off and you have to heat it up again.

Some like it hot, others like to go deep. In medium conditions it's always tough to make that choice, so I follow the fast guys... <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />