HEEL ANGLE AND SPAN DATA VS PCSAIL...very interesting...

[yades]

I have recently made a data comparison (same input data project for a 58ft sailing yacht, under same sail conditions and same beta TW...ecc) between results obtained from PCSAIL and SPAN and have noticed whilst some data are in line...other ones (at true wind speed 20kts and in beta range 35-90 degrees) SPAN gives angles of heel exceeding the deck immerged level in the range 34-36 degrees with a max of 43 deg. !!!?? (have noticed that reef conditions remains constantly at one value !!!). PCSAIL gives instead values in the range of 22-26 degrees which seems reasonable, giving reef conditions from 0,9 to 0,7 and flat conditions from 0,45 to 0,9 up to beta 60° (similar, in this case, to what is recorded by SPAN). Is anyone able to explain the reason for this large discrepancy ?
Is there any possible way to retuned SPAN values to a more acceptable values for heeling angles? Furthermore...why SPAN values does not take into consideration the deck immerged condition (in this case it should have been max 30°) as an ultimate/extreme level for heeling angle permissible??

[Tim B]

How is the righting moment calculated? Does it just take an upright GM, or a discrete set of points on the GZ curve?

What is your estimated angle of heel at that wind speed (at Beta=90)?

Is span using appropriate reef/depowering factors?

Tim B.

[Andrew Mason]

Sounds like the reef and flat variables are not being applied correctly. What version of SPAN are you using, I'll look into it.

[yades]

Originally Posted by Tim B

1. How is the righting moment calculated? Does it just take an upright GM, or a discrete set of points on the GZ curve?

2. What is your estimated angle of heel at that wind speed (at Beta=90)?

3. Is span using appropriate reef/depowering factors?

Tim B.

1. sorry but i'm not familiar with SPAN in that respect
2. about 23/24 degrees from my estimate and about 26 from PCSAIL
3. that's a good question to answer too... ..from what I've been told (I only have the results print out) I presume everything works out on an automatic basis, however I use PCSAIL for the purpose intended being quite accurate, as far as I've experienced.

thanks yr reply

[yades]

Originally Posted by Andrew Mason

Sounds like the reef and flat variables are not being applied correctly. What version of SPAN are you using, I'll look into it.

I am not using SPAN (unfortunately) however, I found PCSAIL fair enough for the purpose intended. Moreover, the print out of the results which I had received, I've been told it belongs to the old version 8.5 .....perhaps that's the answer... it's quite an obsolate version..... or perhaps something has not been processed correctly whilst entering the input data....but what it looks akward to me is that in the print out, under the "Reef" columns the values reported is in general "1" very seldom smaller......
Nevertheless I still believe the resulting output must some how give heeling angles not exceeding the deck immerged heel angle (in this case the value of 24/25 degrees max...am I correct?

thanks your reply/attention

[yades]

the enigma of the non-aligned values between SPAN and PCSAIL has not yet been solved. Has any one got any idea on why SPAN (vers. 8.5) gives answers regarding heel angles (well over 25° - 27°) thus exceeding deck edge immersion and reefing value well over the limits?
What else can be done to align values? it seems like SPAN works everything out automatically...it's not possible to intercept and adjust values of any kind. Is that true?

any reply would be appreciated

[Andrew Mason]

We are up to version 13 now, so 8.5 was a lifetime ago. There have been a lot of changes since then, including a complete rewrite of the SPAN solver.

If you can post the input values for your design I can run it through the latest SPAN and see what happens with the heel angles.

[yades]

Originally Posted by Andrew Mason

We are up to version 13 now, so 8.5 was a lifetime ago. There have been a lot of changes since then, including a complete rewrite of the SPAN solver.

If you can post the input values for your design I can run it through the latest SPAN and see what happens with the heel angles.

tks yrs, values are as follows:

HULL DATA:
FF..... 1,965 m
FA..... 1,654 m
RM2....849,8 kgm/deg
RM20...697,3 kgm/deg
RM40.. 514,1 kgm/deg
MBMX..5,247 m
PIPPA..0,045 m
AMS1..2,600 m2
BTR....4,594
DHKA..3,012 m
ECMA 0
D.......2,595 m
B........4,229 m
WS ...66,590 m2
DISP 19063,1 kg
L.......17,162
LSM1..16,933 m
LSM3..17,558 m
CW.....1273,2

RIG DATA
I.........24,100 m
J..........6,612 m
LP........8,300 m
SPL......7,700 m
SL......20,000 m
SMW....7,480 m
MDT1...0,150 m
MDL1....0,330 m
MDT2...0,150 m
MDL2....0,260 m
HBI......1,727 m
TL ......6,000 m
P.......21,600 m
E........7,140 m
MGU ...2,820 m
MGM....4,910 m
BAS ....2,500 m

much appreciated yr effort
(...however...you recon older SPAN version had bags )
by the way the data belongs to the sailing yacht frantic58 highlighted in the gallery for viewing....

[yades]

would be v. much appreciated receving further comments/results on the subject, on the basis of the data inputs (hull & rig) previously outlined ...

tks in adv. for any answer

[waleed_hanoo]

dear Mr. andrew I have aproblem with a hydromax ,it gives me awrong results and i cant find what is wrong plz if you can help ill be very thankfull
waleed

[yades]

Does anyone have the possibility to insert the data, previously provided on this thread, on a recent version of SPAN and to kindly advise on the results obtained so as just to allow a more fair comparison with SPAN ver. 8.5??
(p.s. the data inserted on this thread belong to the s/y FRANTIC58 - see thread "FBYD 58ft - an example of concept yacht hull lines" or view the private gallery for relevant drawings).

Any help in this respect will be much appreciated

Brgds