Donal,

The "Death Roll" there is a much better adjustment.

Called a "Preventer" It is a line from the end of the boom and taken
forward. With the pressure of the Preventer and the pressure of the main
sheet set, holding the trim, the boom is pretty well stabilised.

If you are using a Vang that's been unclipped and fastened to the deck
or toe rail it do the same thing but can be a PITA if you need to get
rid of it fast, A single line or "Kicking Strap" as you English call
them does the same thing but that can even be a bigger PITA. A good fore
deck crew with a sharp knife can be pretty handy,

How's that Doug. Is that enough talk about "PREVENTERS?"

Ole Thom