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 Boat Design Forums Mast pillars design

#1
03-13-2006, 07:34 AM
 Tom_S Join Date: Mar 2006 Rep: 10 Posts: 3 Location: Vancouver, BC
Mast pillars design

Hello,

I'm designing a sailing boat (7.5m, cruising), and a mini 6.5, and i have to put a mast pillar in both boats. Could someone give me some informations about how to design it (forces acting, the way to dimension the bolts)?

Thanks

(sorry i put the same question in the sailboats forum...)
#2
03-13-2006, 07:40 AM
 dimitarp Junior Member Join Date: Feb 2006 Rep: 19 Posts: 90 Location: Bulgaria
First you need to determine forces that acts at the mast. For this you need to know area of saels and the maximum speed of wind.
#3
03-13-2006, 04:59 PM
 MikeJohns Senior Member Join Date: Aug 2004 Rep: 1938 Posts: 2,689 Location: Australia
Righting moment only

Quote:
 Originally Posted by dimitarp First you need to determine forces that acts at the mast. For this you need to know area of saels and the maximum speed of wind.
Getting there.... but not quite. The max force is due entirely to the ability of the boat to resist the wind heeling moment.

what you actually need is the maximum righting moment. Pretty accurate to use RM30 X 1.5 .

If you take the moment and divide it by the mast height you will get a force normal to the mast head, you now need to calculate a force diagram and find the resulting compression in the mast. Give yourself a factor of safety of around 3 .

If this is beyond you give me the dimensions and the RM and I'll calc it for you.

If you have not calced your RM then thats the next step.
__________________
Mike Johns.
#4
03-14-2006, 03:29 AM
 Tom_S Join Date: Mar 2006 Rep: 10 Posts: 3 Location: Vancouver, BC
Thank you, my next step will be indeed to calculate my righting moment...
#5
03-15-2006, 12:15 AM
 bhnautika Senior Member Join Date: Feb 2006 Rep: 566 Posts: 602 Location: australia
Tom_S mast pillars are the same as a mast they are under compression so you can use Euler’s formula for the appropriate end condition to work out loads.