We should add down-hauls to the discussion of hanked on head sails. A down haul will allow you to tame a hanked on sail during a sudden blow without leaving the cockpit.
Here is a diagram of how I had mine set up...
Keeping the jib sheet taught, head into the wind a little to lessen the pressure on the sail and release the halyard and then pull on the down haul. The head sail collapses into a nice accordion pattern and lays still against the gunwale until the blow is over or you have time to go forward and attach a smaller headsail. This also makes the sail neat and orderly for folding it into a deck or sail bag.
Here is a diagram of how I had mine set up...
Keeping the jib sheet taught, head into the wind a little to lessen the pressure on the sail and release the halyard and then pull on the down haul. The head sail collapses into a nice accordion pattern and lays still against the gunwale until the blow is over or you have time to go forward and attach a smaller headsail. This also makes the sail neat and orderly for folding it into a deck or sail bag.