Andrew,

We are talking about common spinnakers on beach catamarans here, not extreme examples that really have no application on beach catamarans. Sure enough you and others could device a contraption where the spinnaker will lift the bows, although this is much more difficult than you think, but that still doesn't say or proof that spinnaker setups as commonly used on Cats actually lift the bows or not.

Also one of the documents sciencific analyses was done on the Cherub skiff boats. A monohull with a long spinnaker pole and an angle back spinnaker. Still the numbers showed a setup that didn't lift the bows despite the fact that these boats ride with their bows high in the air as many other skiffs.

Also from my own experience; I could get my bow to fly on a 49-er just be placing our weight way back on the wing. Under spinnaker it flew less high when the weight was similary placed back.

But lets stick to the catamarans setups.

Wouter