Rounding a mark:

If rounding a mark to leeward, always do so before you reach it. In order to do this, if possible, keep away from it some distance, and put your helm down gradually; then you will not kill the boat’s way and will give your crew time to get the sheets flattened down. If you come down and take the mark close aboard and then turn it, you will have to put your helm hard down, killing the boat’s way and causing her to sag off to leeward.