If your link returns "ERROR",they did some reorganization on the US Sailing site. PM numbers can now be found under "Offshore"
Portsmouth Ratings Home
http://offshore.ussailing.org/Portsmouth_Yardstick.htm
Current Multihull Classes
http://offshore.ussailing.org/Portsmouth_Yardstick/Current_Tables/Multihull_Classes.htm
Multihull Modification Factors
http://offshore.ussailing.org/Portsmouth_Yardstick/Current_Tables/MH_Modification_Factors.htm
A little help please....when looking at these ratings for F18's, I see the abreviation "SLP" ...what is that?
SLP=Sloop, as in sloop rigged. Sloop can have several meanings, depending on the geographic area & time period. In todays vernacular it commonly refers to a single masted boat, carrying a mainsail & fore sail.
Looking at the Nacra 5.5, you can have a Uni rig,(main sail only), or a sloop rig, main + jib.
ok, Thanks.