stabilitycurves 320-430
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Topic: stabilitycurves 320-430
Posted By: Peter-Blake
Subject: stabilitycurves 320-430
Date Posted: 05 January 2010 at 15:36
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I was wondering why the AVS from the 320 and the 350 are so high
(about 135-140). While it is at the other boats more around 110-120.
So i mixed the curves with fotoshop to find it out.
My feeling is that there must be diffrent parameters used for the curves for 320 and 350 as the AVS to me is very high.
To me it seems that the 320 and 350 are with coachroof and the others are counted without.
Any comments?
Source for the mixing work hanse page hanseyachts.com or hanseyachts.at
 All curves with standart keel (shallow draft will be diffrent)
------------- Blake 370 
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Replies:
Posted By: aquilo
Date Posted: 06 January 2010 at 08:03
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For me it seems that the calculations are done in some inconsistence way I wonder if such computations are regulated/standarized, or will a designer/constructor tweak the premises to get "better" curves?
I've previously seen IMS yardsticks with AVS=114 for the Hanse 320, so where does that number come from, is it rough estimations??
For comparisons:
Elan 31: AVS=132, STIX=34
First 31.7: AVS=131, STIX=31
Dufour 325: AVS=113
(New) Bavaria 32: AVS=125
/Geir
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Posted By: Peter-Blake
Date Posted: 06 January 2010 at 10:15
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I watched again at the original curves: The following can be found as title to the curves: 320 HA320-Hull-Deck-Iron-Bulb-03
350 HA350 Deck-Iron-Bulb-02
370 righting arm (light ship)
400 righting arm (light ship)
430 HA43-3-Keel-05
If you search for the Hanse 540 on hanseyachts.at (not used in my above comparison) you will find the following title
540 Hanse 531 - without coachroof
To me it is now impossible to compare any stabilitycurve if there is not a standarized method.
------------- Blake 370
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Posted By: aquilo
Date Posted: 06 January 2010 at 10:35
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I wonder again: Is it common out there to publish sailboat stability curves calculated without mast/rig etc.. ? Of course it gives meaningful information during hull design / comparisons but for a customer??
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Posted By: Peter-Blake
Date Posted: 06 January 2010 at 11:03
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It only gives comparison if they would use the same parameters for all curves. And it would be much more understandable if they used a complete boat, ready for sailing. A hull only cannot sail.
You are right a curve without the parameter coachroof (i.E. Hanse 540) or without the parameter Mast (I think the Mast is calculated but not shown) says nothing to a customer
BTW: Interesting is also that the Dsiplacement in case of the 320 and the 350 mentioned in the stabilitycurves is about 600 kg higher than in the specifications (both to find on hanseyachts.com). May be it is ment to be the weight for the crew. For the other boats there was no Displacement shown on the curves ------------- Blake 370
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Posted By: aquilo
Date Posted: 06 January 2010 at 11:26
...or full fuel and water tanks
From IMS rating certificate data for Hanse 320:
"CALCULATED LIMIT OF POSITIVE STABILITY: 113.7 DEGREES"
Hanse 320 is "Ocean A" classified (i thought according to EN ISO 12217-2- I.e.: STIX >32 and AVS >(130-0.002*m) (where m=minimum sailing weight in kg) => ~120. Maybe Hanse's classification of the 320 into Ocean A (self classification) is not according to ISO 12217-2?
Some clarifications from Hanse would have been nice here...
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Peter-Blake wrote:Posted By: Gran Onada
Date Posted: 06 January 2010 at 18:15
Interesting, do you have this data for the 350? ------------- Gran Onada IV - Hanse 350 #130 |
Posted By: aquilo
Date Posted: 07 January 2010 at 07:39
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Hanse 350 IMS rating certificate: http://www.hanseyachts.at/downloads/Hanse-350/speed/ha350-ims.pdf - http://www.hanseyachts.at/downloads/Hanse-350/speed/ha350-ims.pdf
Some ISO 12217-2 info: http://content.yudu.com/Ayt7u/IRC09/resources/57.htm - http://content.yudu.com/Ayt7u/IRC09/resources/57.htm
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Posted By: pedrofranco
Date Posted: 08 January 2010 at 15:11
| IMS stability data: comes from the input of the measurements and the software VPP converts that into the data that generates the certificate. Nothing to do with the stabiltity that the designers use. In IMS if the stability test is not done (a elaborated system were you have to put weight on side of the boat, measure the inclination angle , then do it the other side, increase the weight, and so on) there is a given stabilty data that penalizes the boats that don't do the test. Although from 2002 please see this new http://www.sailing.org/3677.php - http://www.sailing.org/3677.php and I quote "The IMS measurement system includes an physical inclination test which, along with other measurements, provides each yacht with a stability factor which must meet the race requirement." |