svbeatrix.com — The website of the Sailing Vessel Beatrix, Kelly-Peterson 44 #276 (1980).
This table is my best guess based on published formulas. Use it for whatever you like - I used it for winch sizing. You can download the
Excel Spreadsheet that generated it which allows you to change the sail areas, etc (anything highlighted in yellow).

Winch Analysis Spreadsheet (Excel 2007-2010 File, 103.8 KB,

Jan 20 2013 23:41
)

Calculated Genoa Sheet Loadings      
Sail Area Load (lbs.) for Apparent Wind (Knots)  
Square Feet 5 10 15 20 25 30 35 40 45 50 55 60  
 Furling Genoa       480        52      207      465      827   1,292   1,860   2,532   3,307        4,186      5,168      6,253    7,441    
 Genoa Part Furled (100%)       385        41      166      373      664   1,037   1,493   2,033   2,655        3,360      4,148      5,020    5,974    
 Working Staysail       160        17        69      155      276      431      621      845   1,103        1,396      1,724      2,086    2,483    
 Storm Staysail       115        12        50      112      198      310      446      607      793        1,004      1,239      1,499    1,784    
 Asym. Cr. Spinnaker    1,295      140      558   1,256   2,233   3,488   5,023   6,837   8,930      11,302    13,954    16,884  20,093    
 Genoa Sheet Load (lbs.) = SA * V**2 * 0.00431      
 Formula Source: Harken (http://www.harken.com/blocks/loads.pdf)     
   
Mainsail Dimensions 100% 75% 50% 28%
P. Foot length of Main in feet 45.3 39.3 32.1 24.0
E. Luff Length of Main in feet 14.6 12.6 10.3 7.7
X. Distance from Aft end of boom to mainsheet attachment point in feet 0.0 -2.0 -4.3 -6.9
R: Traveller Block Ratio 3:1
Calculated Main Sheet Loadings Including Traveller Purchase
Sail Area as % of Main Load (lbs.) for Apparent Wind (Knots)
5 10 15 20 25 30 35 40 45 50 55 60
 Mainsail  100%        23        91      204      362      566      815   1,109   1,448        1,833      2,263      2,738    3,258
 Mainsail 1st Reef  75%        15        59      132      235      367      529      720      941        1,190      1,470      1,778    2,116
 Mainsail 2nd Reef  50%         8        32        72      128      201      289      393      514          650        803         972    1,156
 Storm Trysail / Third Reef  28%       3.4     13.4     30.2     53.6     83.8   120.6   164.2      214          271        335         405      482
 Main Sheet Load (lbs) = E**2 * P**2 * 0.00431 * V**2 /(sqrt(P**2 + E**2) * (E - X)) 
 Formula Source: Harken (http://www.harken.com/blocks/loads.pdf) 
 This formula is not so well accepted as the Genoa Sheet Loadings 
Control Line Loadings
  % of Main-sheet loads Max Load (lbs.) for Apparent Wind (Knots)
        5        10        15        20        25        30        35        40            45          50           55        60
Based on Main Sheet Loadings:   No Reef First Reef Second Reef Trysail
 Outhaul/Cunningham  50%        11        45      102      118      184      265      197      257          325        168         203      241

 




Disclaimer
The contents of this page are an example of a refitting job performed on a single vessel by its owner.  Just because I put it here for your interest and information does not guarantee it will work on your boat, or work at all. Fair winds & smooth sailing. -- Jeff Stander

 


Last modified: July 04 2018 23:38