Are the Portsmouth multihull modification factors designed to even the playing field or discourage modification?
I added a spinnaker to a no spinnaker class and I was doing the math; it seems like there is a possibility that I could compete. I am suspicious because the spinnaker modification factor in particular does not specify sail area limits.
With spinnaker and no crew I am going to have to really sail well though.
Thank you.
I don't really understand all of the modifiers. I did a race last weekend and found out that my "modified" number couldn't possibly make sense. How much do you modify the number for a 6.0 NA with a square top? I have a hard time thinking the square top drops my rating by 2.5 to 60.1 from 62.6 (was not running a spin) and an I20 is 59.3 with a spin. That is crap. Take 62.6 and mult by the mod for "large main" .98 = 61.8. Not that it would have changed my standings that much, but pretty f**cking discouraging at times. If I had ran the 6.0NE chute (which would have been ideal given the lightish winds), I would have been a 60.4 (not sure whether this takes into account my square top which evidently CLEARLY gives me such a huge friggin advantage)
For whatever it is worth, in this race, although the sponsoring yacht clup thanked all the multihulls for playing, they didn't bother to break it up into any classes. Needless to say there were like 4 different classes for monohulls.
Maybe this is my lack of knowledge or theirs but I am still sort of irked.
signed...
frustrated 
oops.. just figured it out- when in doubt, read the manual. mod number = dpn*mod*mf1*mf2.
Still crap though- in answer to the original post. Seems like the mods are designed to discourage mods. I can't see how they would effectively level the field. One design looks pretty good right about now. Maybe I should just go back to recreational sailing and forget about all this crap.
They are designed to level the playing field. It is derived from what data has been submitted. In the case of adding a spinnaker, it seems to me to be fair or maybe a little generous, but that is what it is until the data proves that the factor should be changed. As for the larger mainsail, the squaretop on the N6.0 may not offer as much as a larger main on something else, I don't know. The number will be more accurate with the stock boat because there is more data. Without the modification factors, you have no way to compete at all if you don't want to sail the stock boat.
You hear the complaints about all handicap systems. Hang around the mono sailors and the PHRF discussions go on and on, about whether this boat or that has the right rating or whether they win because of their rating. The only way to really determine sailor v sailor performance is SMOD, because everyone has the same equipment, changing only the the "nut" on the end of the tiller. Then you can decide which "nut" was better.
For whatever it is worth, in this race, although the sponsoring yacht clup thanked all the multihulls for playing, they didn't bother to break it up into any classes. Needless to say there were like 4 different classes for monohulls.
Maybe this is my lack of knowledge or theirs but I am still sort of irked.
signed...
frustrated
oops.. just figured it out- when in doubt, read the manual. mod number = dpn*mod*mf1*mf2.
Still crap though- in answer to the original post. Seems like the mods are designed to discourage mods. I can't see how they would effectively level the field. One design looks pretty good right about now. Maybe I should just go back to recreational sailing and forget about all this crap.
If you have a square top sail, it should have been made to within 5% of the same sail area as your original sail (take a little out of the roach and add it at the head..even just squaring off the head should be within 5%). Then you only have a .995 modification (practically nothing).
Well here are the numbers
DP-N_______________________Standard 2 up_Standard 2 up with spin_solo______solo with spin
Rate P18____________________74.80________71.81________________72.56_____69.65
Rate H16___________________76___________na___________________73.72_____na
Advantage 2 up in 60 min_____-1.27_________-4.61_________________-3.75______-7.19
Advantage solo in 60 min______1.18________-2.17__________________-1.31______-4.75
Rate H18_______________ ___71.4_________na____________________69.26_____na
Advantage 2 up in 60 min_____3.82_________0.48___________________1.34______-2.11
Advantage solo in 60 min_____6.42_________3.08___________________3.94______0.49
I am not trying to complain. I am happy I don't have to disassemble my boat every Sunday. The numbers seem pretty generous.
Advantage 2 up in 60 min = if the other boats have a full crew
Advantage solo in 60 min = if the other boats are solo
I am not really concerned with winning or loosing, just having fun with the group.
Matt
Still crap though- in answer to the original post. Seems like the mods are designed to discourage mods. I can't see how they would effectively level the field. One design looks pretty good right about now. Maybe I should just go back to recreational sailing and forget about all this crap.
Amen brother!
Handicap racing at best is a stop gap and is designed for only one thing and that is to allow different boats to sail together. Take handicap racing with a grain of salt.
Matt
Fun? Absolutely. But I'll bet most people feel a strong correlation between fun and competence i.e. the better you are at something, the more fun it is to do. NOBODY likes being dfl!! 
I see my thread being hijacked. We will do our best within the grounds of keeping it fun.
Matt