Help with Portsmouth - Supercat 15

[DanBerger]

I need some help on determining a fair Portsmouth rating for my Supercat 15 sloop.

It is my understanding that the 15 Uni is a 1-up boat, but the US Sailing table doesn't specify the Sloop being 1- or 2-up. I'm assuming 1-up.

Since the Supercat 15 Sloop (SC152) rating is (77.0) I know it is a dead class, but there is also no Beaufort rating provided and I don't know how to calculate it (if it is a calculation).

The Nacra 450 Turbo is practially the same weight, length, beam and sail area and is rated:
Nacra 450 Turbo 1-up N450T 76.9 80.5 79.6 77.0 74.4

SuperCat 15 Sloop SC152 (77.0)
SuperCat 15 Uni SC15 78.0 83.5 79.5 77.5 73.2

It wouldn't bother me if I just used the 450 numbers. It would hurt my rating, but that (to me) is better than artificially helping my rating and therfore cheating.

Also, I have a self-tacking jib which is slightly smaller than the original jib. I can't find a rule that would effect that change, too.

[Matt Haberman]

Dan,

The DPN for the SuperCat 15 Sloop rig was derived using a crew of 2. The Self-Tacking jib should not have any impact on your DPN as there is no adjustment for it. Historically the SC15 handicap has been pretty accurate so I would suggest using it versus the 450's numbers. If you need wind ratings you could use the 15 UNI numbers as a baseline and then adjust them proportionally for the Sloop rig.

[DanBerger]

Thanks!

I assumed the Sloop rig was a single hand number because I thought the 15 uni was a single hander. I'll just have to calculate that adjustment as well.

Can we get an official factory number for the adjustments??

[DanBerger]

This is what we (our Vice Commodore) have calculated for the next race, single handed Sloop rigged:

(74.7) 78.5, 77.8, 75.1, 72.6

This means the single handed Hobie 16s owe me time

[Matt Haberman]

Dan,

The boat manufacturer doesn't generate portsmouth numbers, US Sailing generates them based on race data. That being said, here is what I have come up for a double handed SC15 Sloop with using the 15UNI wind adjusted numbers as a baseline.
DPN= 77
0-1= 82.4
2-3= 78.4
4 = 76.5
5-9= 72.3

I would then adjust these down using the L4 (0.97) adjustment for sailing with less then 70% minimum crew weight. You should use one of the other adjustments (L1, L2 or L3) if you weigh more then 182 lbs (70% of 260lbs). This would move all of these numbers upward a little bit.
DPN=74.7
0-1= 80.0
2-3= 76.1
4 = 74.2
5-9 = 70.1

Locally this is how we handle a gentlemen that sails his SC17 singled handed with the jib. Sometimes he does very well, and other times he has a hard time sailing to the number. Hope this helps.