In SCHRS, F18 is the scratch boat. It's correction factor is 1 and everything else is based off it. Acat and F16 (2up) are rated the same). It's a little tough to compare them because the resulting correcting factors are a bit different.
To really compare the ratings, I've flipped around the formulas so that we are comparing them based off an elapsed time of 30 minutes for the F18...basically making it the scratch boat in both systems. I then took that corrected finished time and backed out the other boats elapsed times as if they all perfectly tied on the handicap corrected times.
Anybody step in here if I screwed this up - I didn't double check these numbers. (the code window maintains spacing in the table that would otherwise be ignored by the forum software)
Elapsed SCHRS Corrected
Acat 00:30:03.6 1.002 00:30:00.0
F16 (2) 00:30:03.6 1.002 00:30:00.0
F18 00:30:00.0 1 00:30:00.0
H16 00:34:21.0 1.145 00:30:00.0Under portsmouth, again, normalized so the F18 has an actual 30 minute elapsed time and backing out the other boat's elapsed times assuming a handicapped tie, we have the following for Portsmouth/DPN. You can really ignore the value of the "corrected" times. All that matters is that the end result is a tie between the boats where the F18 ran the same length race in both scoring systems.
Elapsed DPN Corrected
Acat 00:31:00.8 64.5 00:48:05
F16 (2) 00:30:17.6 63 00:48:05
F18 00:30:00.2 62.4 00:48:05
H16 00:36:32.6 76 00:48:05
So, in this case, Portsmouth is considerably different on the ratings and makes it harder on the F18 (I'm biased anyway). Also notable is that the Acat and F16 (2up) are rated differently under Portsmouth but considered equal under SCHRS.
Under Portsmouth, the F18 would need to beat the F16 by 18 seconds to correct over them. SCHRS says it only needs to be 4 seconds.
Under Portsmouth, the F18 would need to beat the A-cat by right at 1 minute in a 30 minute race to correct ahead of them. Under SCHRS, it's only 4 seconds.
Under Portsmouth, the F18 would need to be 6:33 seconds ahead of the Hobie 16 to take the win. Under SCHRS, the F18 would need to be ahead by 4:21 to take the win.
In summary, SCHRS seems to rate the boats significantly closer together than Portsmouth does. Frankly, I think the existing Portsmouth numbers are closer to reality than SCHRS.
