T&T: Anchor,chain,rope specs and use - wind speed/force table

Bob McLeran rmcleran@ix.netcom.com
Fri Apr 20 09:23:41 EDT 2007


Here's a copy of a spreadsheet with figures for various wind speeds and 
areas (originally posted by Capn Wil Andrews). You'll need to copy and 
paste it into a document with fixed fonts and then add some spaces in 
order to arrange the columns properly. The formula used is at the bottom 
of the tables.


Cd = 0.70 (Sail 
Boats)                                                                   
        WIND SPEED IN KNOTS 
----->                                                           
Sq Ft    |    10    20    30    40    50    60    70    80    90    
100    110    120    130    140    150    Sq Ft
50    |    12    47    107    190    297    427    581    759    961    
1186    1436    1709    2005    2326    2670    50
75    |    18    71    160    285    445    641    872    1139    
1442    1780    2153    2563    3008    3488    4004    75
100    |    24    95    214    380    593    854    1163    1519    
1922    2373    2871    3417    4010    4651    5339    100
125    |    30    119    267    475    742    1068    1453    1898    
2403    2966    3589    4271    5013    5814    6674    125
150    |    36    142    320    570    890    1281    1744    2278    
2883    3559    4307    5126    6016    6977    8009    150
175    |    42    166    374    664    1038    1495    2035    2658    
3364    4153    5025    5980    7018    8139    9344    175
200    |    47    190    427    759    1186    1709    2326    3037    
3844    4746    5743    6834    8021    9302    10678    200
225    |    53    214    481    854    1335    1922    2616    3417    
4325    5339    6460    7689    9023    10465    12013    225
250    |    59    237    534    949    1483    2136    2907    3797    
4805    5932    7178    8543    10026    11628    13348    250
275    |    65    261    587    1044    1631    2349    3198    4176    
5286    6526    7896    9397    11029    12790    14683    275
300    |    71    285    641    1139    1780    2563    3488    4556    
5766    7119    8614    10251    12031    13953    16018    300
325    |    77    308    694    1234    1928    2776    3779    4936    
6247    7712    9332    11106    13034    15116    17353    325
                                                                   
                                                                   
*************************************************************                                                                  
 
                                                                   
Cd = 1.00 (Power 
Boats)                                                                   
        WIND SPEED IN KNOTS 
----->                                                           
Sq Ft    |    10    20    30    40    50    60    70    80    90    
100    110    120    130    140    150    Sq Ft
50    |    17    68    153    271    424    610    831    1085    
1373    1695    2051    2441    2865    3322    3814    50
75    |    25    102    229    407    636    915    1246    1627    
2059    2542    3076    3661    4297    4983    5721    75
100    |    34    136    305    542    847    1220    1661    2170    
2746    3390    4102    4882    5729    6644    7627    100
125    |    42    169    381    678    1059    1525    2076    2712    
3432    4237    5127    6102    7161    8305    9534    125
150    |    51    203    458    814    1271    1831    2492    3254    
4119    5085    6153    7322    8594    9967    11441    150
175    |    59    237    534    949    1483    2136    2907    3797    
4805    5932    7178    8543    10026    11628    13348    175
200    |    68    271    610    1085    1695    2441    3322    4339    
5492    6780    8204    9763    11458    13289    15255    200
225    |    76    305    686    1220    1907    2746    3737    4882    
6178    7627    9229    10984    12890    14950    17162    225
250    |    85    339    763    1356    2119    3051    4153    5424    
6865    8475    10255    12204    14323    16611    19069    250
275    |    93    373    839    1492    2331    3356    4568    5966    
7551    9322    11280    13424    15755    18272    20976    275
300    |    102    407    915    1627    2542    3661    4983    6509    
8238    10170    12306    14645    17187    19933    22882    300
325    |    110    441    992    1763    2754    3966    5399    7051    
8924    11017    13331    15865    18620    21594    24789    325
                                                                   
NOTES                                                                   
                                                                   
Loads based on the formula : D = 0.00339 * Cd * V * V * 
S                                                                   
                                                                   
D = pounds of pressure on boat created by wind 
velocity                                                                   
                                                                   
Cd = the coefficient of 
drag                                                                   
                                                                   
V = wind velocity in 
knots                                                                   
                                                                   
S = square feet of boat exposed to 
wind                                                                   
                                                                   
Temperature = 59F. Barometric pressure = 29.92 in. 
Hg.                                                                   


<><><><><><><><><><><><><><>Mozilla Thunderbird<><><><><><><><><><><><>
Bob McLeran and Judy Young                       Manatee Cove Marina
M/V Sanderling                                   Patrick Air Force Base
Hampton 35 Trawler                               Melbourne, Florida



On 4/20/2007 8:48 AM, Robin wrote:
>  What's what's a reasonable relationship between anchor holding specs,
>  chain working load, and nylon breaking strength? These are the way
>  the three are routinely rated in marine catelogues.

<snip>


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