In connection with hard winds the sail is reduced in size to ensure that the ship does not heel over. It is possible to reef both before sailing out – if the weather forecast anticipates a strong wind – and while sailing.
If one reefs in advance, this is done from the top of the sail – here there is the possibility of taking two reefs (reducing the size of the sail in two stages).
If one reefs while sailing, the reefs are also taken from the top – if the wind and the waves permit this. In situations in which the weather, however, makes the ship move violently in the water, and consequently heel violently when the sail is right down and the yard is laid down along the ship, the sail will be reefed from below. Each reef takes about 125 cm off the height of the sail. The sail is thus reduced with approx. 19 square metres for each reef.
While the reefing is being done, the yard is lowered corresponding to the amount of rope.