Trying to figure out a PHRF rating for my Hobie Getaway to race on Wednesday nights. GYA PHRF committee will not give me an XPHRF rating since it is a multihull.

Portsmouth rating is 83.3

Apparently the conversion for Portsmouth to PHRF is:
PHRF=(D-PN - 55) x 6

That would give me a PHRF Rating of 169.8
I am no expert in PHRF, but that seems like a really generous rating for a beach cat (even if the Getaway is a slower than most beach cat that can't really point at all).

For reference, the E-Scow Portsmouth is 72.6 and GYA PHRF is 54.