I watched a H14 sailor this past weekend and he ran as much rake as he could (blocks right at each other) and then ran extremely loose shrouds so that he could rake it back forward downwind. He used a fairly heavy line (~3/8") from the front bridle chainplate to his front beam where he cleated it off. Pulling on this line downwind collapsed the forestay and bridles towards the tramp which brought the mast forward. He was very fast and deep down wind.

Tim Dry
MHRA Commodore
http://www.catamaranracing.org