Mary,

The following is based on my experience sailing A-cats and F-18HT's.

The jibing angle of an A-cat downwind is typically around 95-100 degrees in light air (mild thing) and that is about the same as any two man sloop without a chute. From my experience racing F-18HT with chute, it was also about that same angle in light air.

As the wind increases and you start doing Wild Thing (flying the windward hull), the angle gets bigger at first. In marginal hull flying conditions, the angle probably increases at least 20-30 degrees. As it gets windier (around 15 knots), the angle gets closer to 90 degrees and when it is approaching our wind limit for racing, is typically less than 90 degrees. Most spinnaker boats follow the same transition and will have even deeper angles as the breeze increases.

IMO, tacking downwind is what makes catamaran racing fun and challenging!

Bob Hodges