80% of the hulls were made with a centerboard, 20% have a deep fin keel. That's certainly a big difference in PHRF. Beyond that, it's just a matter of rigging and sail plan. Tartan 3700 is completely different of course.
That said... I Googled around a bit and found this list for the Chesapeake Bay PHRF. There is a Tartan 37-2 listed and Tartan has parts for them... I'm not sure where they fall in the history but that's not us. Pretty sure 37-3 is the 37C
Quote:
138 4P TARTAN 37-3 SK AS RFA 137 03/25 MRYC BLEW BAYOU 11 52372 R. M. Rosenfeld
138 4P TARTAN 37-3 SK RFA 150 03/25 CBYRAN SEEADLER 11 37235 W. B. Read
Abbreviations used as suffix to Class/Length: ODR-One Design Rating, UC-Unconventional Craft, AL-Aluminum Mast, AS-Asymmetrical Spinnaker, RFA- Roller Furling Above deck, RFB-Roller Furling Below deck, FP-Fixed Prop, MOD-Modified, SM-Short Mast, TM-Tall Mast, VTM-Very Tall Mast, CB-Centerboard, OS-Oversize Spinnaker, OL-Oversize Luff, OP-Oversize Pole, BS-Bow Sprit, SD-Shoal Draft, SK-Swing Keel, SHK-Shortened Keel, IK-Iron Keel, WK-Wing Keel, DK-Drop Keel, MH-MastHead rig, FR-Fractional Rig, RAC-Racing version, YWL-Yawl, CUT-Cutter, OB-Outboard engine, IB-Inboard engine, CPA1, CPA2, CPA3 - Boat assigned to class PHRF A1, PHRF A2, or PHRF A3, GR-Gaff Rigged..
Full doc at
http://www.phrfchesbay.com/validlist.pdfHigh Flight was once given a much envied 153 (Lake MI PHRF) but we have a loose footed furling main/full keel and I think got points for the dodger (well I'm sure we tried anyway
). This was just Jib and Main - no spin. It was for a beer can series and is several yrs out of date.