The slot effect is something special. This describtion allmost exclusively used to describe the interaction between the jib and the mainsail. It is very dependendable on a proper setting/tuning. The slot between the genaker and mainsail is very much bigger and I seriously doubt wether there even is a noticable slot effect between the genaker and the other sails. There is undoubtably a skewing of the airflow which has a positive effect with respect to preventing stalling the main, but the performance enhancing slot effect that the jib provides is something different. This is caused by a jet of fast moving air that is produced very near to the surface of the mainsail. This jet prevents macro turbulence to come into contact with the mainsail and thus lowering the sucktion force. Typically the slot of the jib is some 0,3 to 0,1 mtr wide (a foot or less). The genaker slot is at least a 1,25 mtr. wide and probably even more. I don't think that this much larger slot is capable of producing anything near as effective jet of air as the jib does. If your jib sheeting is a little off then this slot effect is quickly lost.



Having said this I would like to answer Kirts question.



I should have written The distance from the jib forestay to the genaker luff And the distance between the daggerboard and the genaker luff between the 49-er and F16HP are very similar. I should not have used the word slot.



With this similar distance the capability of carying equal sized genaker is secured as well as the fact that that both rig harvest the same crosssection of wind when they're both moving equally fast. Also the lee/weather helm tendencie will be comparable.



In effect there is no BIG theoretical difference between a LONG poled skiff rig and a SHORTER poled F16 rig (with respect to this point)



That is what I weas trying to say.



Kirts idea effectively adds a jib to the boat and I would consider that in violation with the rule that says the 1-up sailing mode sailplan comprises of a mainsail and genaker only. On the other hand, I won't protest it for I'm quite sure that the disadvantages are bigger than the advantages.



Further I don't think that a shorter pole is needed for 1-up sailing. Mainly because the only reason to do this is the jib slot effect and only a proper cut jib can provide that. The other effects of a genaker, like it's contribution to skewing of the airflow will be much the same between a sloop rig and a uni rig.



I hope answers the question.



Wouter