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Darn DPN numbers

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PTP
 PTP
(@CaptainPP)
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[#17638]

To all you people out there who may know this answer.. please HELP!
I have a 6.0NA with a new square top main and stock jib. What is the correction? I have written to my sailmaker to figure out whether this main is larger by 5% than stock but have not heard back. He originally said it was the

max

size main.
Secondly, how can you tell whether the DPN on the USSailing web site includes a square top main? For example, take the 6.0NE which has a huge spinnaker. How can I tell whether that number includes a square top main?


 
Posted : May 20, 2006 10:48 am
Chris9
(@chris9)
Posts: 881
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The 6.0Ne does not include a Squaretop main. What we did was to lay our square top down on the ground then laid the regular main on top and let everyone judge weather is was truly bigger or not. You may want to try that. With our square top it was fairly obviouse that it was not bigger by much and everyone agreed that it wasn't bigger by 5%.


 
Posted : May 20, 2006 1:11 pm
PTP
 PTP
(@CaptainPP)
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Thanks chris- I will try that when I can borrow someone's pin top main.


 
Posted : May 20, 2006 1:48 pm
(@john5583)
Posts: 877
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We got into this pretty hot and heavy last year with our sailing club and a few of our regattas with “your sail is not legal hissy fit.” To simplify this issue we just stated “if your cat is not using the original style sail it came with or has a new square top you’re taking a ML (.980) modification – end of story. It seems that many of us had done the square tops on our “old school” cats (those designed prior to 1997) and a few had pushed the limit.

Speaking of DPN - this concern came up in one of our planning meeting and this has to do with the rating system as a whole – many think that it is unfair to be matched with the newer technology due to the fact that US Sailing is not (at least in my opinion) reviewing the data points on the older style boats – N58 N60 P19 etc…. Try to explain why an NACRA 5.8 has a 6% better handicap over an F18 or outfit a NACRA5.8 with all the new goodies Sq Top, Spiny etc… and you get <.01% handicap. That said, we are thinking of having two classes for our beachcat classes this year – one being New Style – all boats designed and built after 1997 and “Doing it Old School” – all designed and built prior to 1997. Any thought suggestions?


 
Posted : May 20, 2006 4:21 pm
(@davea)
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I agree that comparing the newer boats to the older ones leads to problems. I think the solution is to separate out the newer spin boats into their own category.. We are using 3 classes this year:
low portsmouth - which is all the older non spin faster boats such as hobie 20, Nacra 6, 5.8, prindle 19 etc
high portsouth - hobie 16,17,18, dart 18 etc
F18 (but you could make this all spin boats)

This seems to work betterm although there are still problems with some boats ratings.
Dave
Ontario Racing Catamaran Association
http://www.f18.ca/orca


 
Posted : May 21, 2006 9:14 am
(@tcatman)
Posts: 3070
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Why do you think that the PN numbers of OLD designs be adjusted upwards to slower and slower ratings?

We assume that all the boats that are racing are

in racing shape

That means... a stiff boat, and racing sails....

Would you show up to a car race... with a 15 year old car that's leaking oil and claim you need a head start?

Of course not...

Do you expect to show up at a Hobie 16 race with 10 year old sails on a vintage boat and expect to compete with the A fleet at the Syracuse mad catter .... Of course not...

Continually evaluating the data for the Prindle 16 is ridiculous.. The class does not hold a nationals much less a one design start, it's no longer built and it's likely that the sails are 10 years old when it does race in an open class. What would happen if you take a new Prindle 16 with a new class legal sail and put a P16 sailor from back in the day... on the boat.... If the ratings are kept with integrity... this fellow sails the boat to its rating and he competes against other sailors sailing their boat to the rating.

If you pollute the rating by allowing it to creep upwards... you simply make the race unfair for all of the sailors.

The argument that you are raising is the BEST argument for a measurement system... eg texel. (A point of view that I am coming around to after their latest round of updates)

The solution to your problem is not adjusting the ratings of the BOAT... rather.. you adjust the rating of the skipper on the boat.... After all... he determines the budget for his racing program... (eg he who spends nothing... to someone who invests in decent sails year after year.) This is called a personal handicap and it solves your problem of old equipment and a huge range of sailing skill. Races that are based on your ability to beat your self keep it fresh for all racers.

Splitting the fleet into a good ol boat fleet is fine... It does not undercut the integrity of a rating system and puts the racers into a class where everyone is playing with the same commitment. Score them in the overall race as well and everyone is happy.

The monohull's do this as well... on the Chesapeake Bay... they have the Good Ol Boat regatta... this is a race for those vintage 20020 year old boats that are out and want to do a race, its very popular ... AND these sailors race but once a year and perhaps in some beer can races on the weeknights. This solution recognizes the differences in commitment to going sail boat racing.


 
Posted : May 21, 2006 12:42 pm
PTP
 PTP
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The N6.0 has an interesting history- given all the different rigging possibilities. Take, for example, the fact that if I run the boat as a 6.0NA, my rating is 62.6 witha correction for a square top (I have heard back from the sailmaker and it is not a larger sail) is 61.6 or so. HOWEVER, I have a 350 sq ft NE spin.. so my rating for a N6.0NE would be 60.4. Corrected for the square top would be 60.4*.990*.99=59.4 NOW.. lets say I don't run the spin! then mult that 59.4*1.03*1.02= 62.5!!!!! So which do I do? the 61.6 or the 62.5!!

Figured that out at work... I could further play with the Express rating and see what comes up. In the end, I guess you need to be sportsmanlike <img src=

alt=

/>


 
Posted : May 21, 2006 10:42 pm
Chris9
(@chris9)
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Can be a scorer’s nightmare! I ended up making a chart because of all the possibilities. Last year I even forwarded it to Mark before a CRAC race so he would have the numbers at his disposal come scoring time. Keith, our weekly race scorer, poor guy had to ask every night

How were you configured tonight?

We had all these possible configuration and even raced them all at least once:

- Standard 6.0 NA sails
- Standard 6.0 NA sails plus spin; essentially the 6.0NE, but our spin was bigger
- 6.0 NA with square-top(Less than %5) and big jib
- 6.0 NA with square-top(Less than %5)and big jib and spin(Incidentally, this configuration owes time to the I20 in most of the wind ranges.)
- 6.0 NA with square-top and NA jib and spin

Throw in single handing any of these configurations and theres another factor, didn't actually do this last year.

In my opinion, if your boat is an NA your not an express regardless of the sails you choose to use.


 
Posted : May 22, 2006 7:35 am
(@wyndsurf2000)
Posts: 1137
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I too have a 6.0 NA with a square top and spinnaker. I am usually assigned a rating of 59.8.


 
Posted : May 22, 2006 9:22 am
(@Anonymous 31079)
Posts: 891
 

Mark
quote >

The argument that you are raising is the BEST argument for a measurement system... eg texel. (A point of view that I am coming around to after their latest round of updates)

Are others so inclined now Mark?

It is a very difficult task , rating diverse designs of catamarans .

Just my 2 cents,but if a measurement system is used the one thing to retain is the PN scale and the corelation between distance sailed and time. The Texel rating scale should be converted to Pn scale to somewhat reflect this if it has not already been changed or converted .

All MUCH easier said then done.

It will benifit the sport in numerous ways ,and the rewards within are evident to many.


 
Posted : May 22, 2006 9:41 am
(@tcatman)
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Carl... Good to have you back!

Mark


 
Posted : May 22, 2006 12:42 pm
(@john5583)
Posts: 877
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Where can I get the Texel matrix?


 
Posted : May 26, 2006 10:55 am
Tony_F18
(@Tony_FX1)
Posts: 2315
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Here ya go
http://www.watersportverbond.nl/content.asp?me_id=468


 
Posted : May 26, 2006 11:56 am
(@john5583)
Posts: 877
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Thanks for the link – appreciate it. In looking at this and if we were to use this scale, how would we figure the corrected time? I am thinking it may be with the following example using a NACRA 5.8 with Spinnaker (Texel #98) and an Inter 20 with Spinnaker (#95). The 5.8 completed a course in 2 hours and 23 minutes (143 Minutes) and the Inter 20 completed the course in 2 hours and 22 minutes (142) minutes.

To calculate the score we would multiply the Texel rating by the total minutes and the lowest number being the winner?

NACRA 5.8 – 143 X 98 = 14014
Inter 20 – 142 X 95 = 13632

Looking at this and with the measurements etc... it looks allot like ORCA, or am I getting the wrong jest of it?


 
Posted : May 26, 2006 4:52 pm
(@john5583)
Posts: 877
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Opps – just found on the web site how to get the CT – very similar to Portsmouth:

Using the same example:

NACRA 5.8 w/Spin - 2 hour 23 minutes = 2.35
Inter 20 w/Spin – 2 hours 22 minutes = 2.34

N5.8 – 2.35/98*100 = 2.397
N20 – 2.34/95*100 = 2.463

The 5.8 wins!

This is a very simple system predicated on all of the boats entering having a certified rating number which is a similar operation to the ORCA multi-hull organization.

Hmm- maybe this should be considered just so long as the skipper and crew are not rated as they are with ORCA.


 
Posted : May 26, 2006 5:17 pm
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