Powerex Carbon 70 mast

Powerex Carbon 70 mast

Post by Fischer Michael » Tue, 16 Jul 1996 04:00:00


Hi,

I think I read a post a while ago about the positioning of a mast in a
mast sleeve.  Is it wise to put the same side of the mast in compression
or tension all the time?  For example, if the mast is not positioned the
same way all the time in the sleeve, a specific side of the mast will be
in compression one time and then perhaps in tension the next.  Would it
better to make sure the one side recieves compression all the time?  Any
comments?  

FISH

 
 
 

Powerex Carbon 70 mast

Post by S1turn » Wed, 17 Jul 1996 04:00:00

Quote:
>>  For example, if the mast is not positioned the

same way all the time in the sleeve, a specific side of the mast will be
in compression one time and then perhaps in tension the next.  Would it
better to make sure the one side recieves compression all the time? <<

Just off the top of my head, I'd think that your mast would LAST LONGER if
you randomized the rigging rather than putting the forces on it the same
way each time.

 
 
 

Powerex Carbon 70 mast

Post by Gary Wo » Wed, 17 Jul 1996 04:00:00


Quote:

>Hi,

>I think I read a post a while ago about the positioning of a mast in a
>mast sleeve.  Is it wise to put the same side of the mast in compression
>or tension all the time?  For example, if the mast is not positioned the
>same way all the time in the sleeve, a specific side of the mast will be
>in compression one time and then perhaps in tension the next.  Would it
>better to make sure the one side recieves compression all the time?  Any
>comments?  

>FISH

Hmmm... good question

According to my new warantee card on Powerex, carbon masts don't like to
be left rigged for a long period of time, espacially in the sun.  The
card says the mast may adopt the rigged curve - no doubt affecting the
strength of the mast as well. Probably this means that always rigging
them the same way would have a similar but much reduced effect ?
On the other hand, I hear that many top sailors always rig a sail according
to the 'natural' curve of the mast - the small amount of curve from dead
straight that any mast will have.

Maybe one of you techo-wizards can shed some light on this one ?

 
 
 

Powerex Carbon 70 mast

Post by sailq.. » Wed, 17 Jul 1996 04:00:00

Quote:


>>Hi,

>>I think I read a post a while ago about the positioning of a mast in a
>>mast sleeve.  Is it wise to put the same side of the mast in compression
>>or tension all the time?  For example, if the mast is not positioned the
>>same way all the time in the sleeve, a specific side of the mast will be
>>in compression one time and then perhaps in tension the next.  Would it
>>better to make sure the one side recieves compression all the time?  Any
>>comments?  
>On the other hand, I hear that many top sailors always rig a sail according
>to the 'natural' curve of the mast - the small amount of curve from dead
>straight that any mast will have.

I'm no techno wizard but have been using carbon masts for about 12
years now and have never had a failure of any kind.

I have a advanced composites engineering book and what little I can
understand leads me to believe that the aforementioned "pros" may be
right and this agrees completely with my experience.
If you get a new mast, try to match the joint so it fits with no gaps
at the vetical parting line of the joint (ie twist it around until it
has the least possible gap). Then mark the top in relation to the
bottom with a paint marker or tape.
Then roll the mast on a smooth surface or sight down the mast while
rolling it on the tip. If it has a definite "high side" mark this as
the front and always put it toward the front of the rig.
My north Xcellerators have serial number stickers on the top and
bottom and when aligned  I always put this to the front.
My un high tech analysis is that if you bent the mast in the same
direction all the time you will eliminate (to the extent possible)
something  called  "interlaminar stress" which means that adjacent
layers of composite fibers are not forced one way today and the
opposite way tomorrw which could eventually damage the interlaminar
bond and weaken the mast.

It works for me, the pros seem to agree, and the textbook suggests
that it's a good idea.
Go for it!


F2 Boards;North Sails/Rigs;True Ames/Rainbow; SpeedTech .