If I understand the Brit's summary of the Finn's analysis, there is a net force pushing down on the bows from a spinnaker, but it is substantially less than if the same sail area was on a high aspect rig with the fore to aft CofE at the same distance from one end of the boat? Experience seems to contradict the interepretation of the numbers. Even rereading the article seems to say the same thing, that bows are flying and the boat feels steadier, but the numbers don't lie, so there is more pressure on the bows. In an effort to make sense of both I wonder if the explanation is that while some additional pressure is put on the bows the additional foward speed.... (does something causing the leeward bow to actually ride or float higher?) As I think about this more, I'm still having trouble with a net down force. If you observe the end of the spin pole properly preloaded or otherwise, it bends up as the loads increase. Although part of that is how it is supported and how the loads are applied, if there is a net down force it has to be applied at one of the 3 corners and its not happening at the clew or the tack. (loosen them under some load and see which way they go) Looking forward to some logical, factual input.

Wouter, I'm unable to find link to Bethwaite's article on your site. Is it there and I'm just not finding it?

Also, Wouter, my recent experience and Randy Smyth's article in White's book on spinnaker's indicates that although you can sail deeper with a spin, and you feel like you are going fast and you have flow over all sails, you are sailing too low. Under a spin you need to be sailing higher than what feels right, about the same as non spin boats, but going 'way' faster.

Todd, just because you can pitch pole with the spin up doesn't mean there isn't more force lifting the bows with a spin than without. There is a potential for considerable pitching moment if the boat is not trimmed properly