To go fast downwind and on the reaches on medium and high wind on a laser what you have to do is :
SURF, SURF , SURF!
You have to ride all the waves that you can catch.
Downwind sail by the lee, i.e., release your mainsheet more than 90 degrees and pass the straight downwind direction. The boat will be more stable than straight downwind and easier to surf the waves. You probably need to sit on the rails inside and one knee on the bottom of the cockpit.
The vang need to be with the correct tension. Put a telltale on the top batten, it needs to be flying parallell to the batten. If it goes up, the vang is too loose, if it hides behind the sail the vang is too tight.
The same for the vang tension on the reaches. If you have the new vang system, it will be easy for you to adjust the vang on the reached and downwind. If not, make marks with a permanent markers with aproximate adjustments for light, medium and heavy winds on the vang line, so you know what tension you are using.
what rules do people have for how far to let the mainsheet out?
i find that mine tends to be too far out, so im less stable? it just doesn't feel as good (and i dont go as fast) but i have trouble finding a happy medium. any advice? my mainsheets really long, which i think is definitely one factor contributing to the overease, but i dont know how short to make it...
Let your kicker off. Heel the boat to "windward" and use your bodyweight/rudder to keep you upright:
When you heel to windward, bear away more and vica versa.
Using your rudder is very effective at keeping you upright.
I see what you are trying to mean, but your wording may be misleading to any inexperienced readers here. So, I'm trying to correct it.
"The direction you are heading" can NOT be dead downwind if you want to sail by the lee.
You need to turn further away from the wind than dead downwind to sail by the lee! As if you were on a broad reach, but with the boom not on the normal, leeward side, but on the side of the wind!
Sailing by the lee, you let your boom out past 90 degrees to the centerline of the boat. In light air, as much as 35-40 degrees past it! In stronger air, maybe just 20 degrees past it, and in heavy air, not more than 5 degrees past the square to the centerline.
So, with boom that far out past 90 degrees to centerline, there is no way that you can sail "by the lee" while heading "dead downwind". (Draw it on a piece of paper.) For the entry point of the wind to the sail to be the leech and the exit point to be the luff (which is the definition of "sailing by the lee"), you need to head considerably lower than "dead downwind".
On the leeward leg of any course, suppose the leg is set "correctly" (that is, the direction of the leg is in line with the median true wind direction, with no current).
When the wind direction and the leg direction match like this, if you start sailing by the lee, you will not be heading towards the leeward mark: On Starboard tack (and by the lee), you will be heading much much more to the left of the leeward mark. On Port tack (and by the lee), you will be heading much much more to the right of the mark. So you will be sailing a longer distance to the leeward mark.
Of course, the wind is never steady, it can have persistent shifts and oscillations, and the tactical questions become when to sail by the lee, on which tack, and when not to, and when to gybe, and when not to, and when to oscillate your heading and sheeting angle between a by-the-lee and a broad reach (the so-called "Zig Zagging" or "S-curving").
Only when a course is set WRONG by the Race Committee can you sail a leeward leg by the lee, on one tack, from beginning to end. And even then, you are not sailing "dead downwind" or with the wind "dead astern".
When describing "sailing by the lee", using the term "you will be heading dead downwind" is just plain wrong in general. Regardless of whether "dead downwind" describes the direction of the boat relative to the leeward mark, or relative to the wind.
So, if any of you are just trying to master "sailing by the lee", forget the idea of sailing "dead downwind" to make it happen.
If you have a wind indicator, try this: When really sailing "dead downwind", your wind indicator will point along the centerline of your hull. But for sailing "by the lee", you need to turn more downwind (i.e., pull the tiller more towards you) so that the wind indicator will begin pointing almost in line with your boom (which is all the way out, past 90 degrees)! You are on a broad reach with the boom on the "wrong" (windward) side!
Bearing more and more away from dead downwind to a by-the-lee course, if you look at a wind indicator mounted on the mast right at the gooseneck, you will see the wind indicator start to rotate wildly. That heading is just the "edge" of your by-the-lee course for that wind and that boom angle.
Of course, properly located telltales can be of great help in detecting by-the-lee airflow (and stall areas and flow separation) on the sail (at least for non-Olympians Remember that what is more important is always proper flow along the BACK (leeward) side of the sail.
Finally, what makes "by the lee" sailing an advantage is not only that it can be fast, but that it increases the stability of the boat.