Conference unifix::sailing

'everything else being equal' my bet is that the old jenny
is porous and the rain sealed the jenny and reduced its losses, maybe
a combination of less air going THROUGH the sail, and reduced turbulance
over the sail.

My feeling is that rain is unlikely to affect the performance of a sail, old
or new.

Other factors to consider - Heavy rain will often flatten the surface of the
sea, which may affect the relative performance of different boats and crews.

However, I think the most likely explanation is psychological. Some people
hate the rain, and will spent more time cowering under their hoods than
concentrating on thier course or trim. A bit like sailing at night, where
huge gains in perfomrance are possible givin the right attitude.

Chris

    What I don't understand is how the rain would only favour an old Genoa
    why would the same effect not be had on a new one ?
    
    My feeling was that an old Genoa was more deformed than anything else,
    and that was what caused the loss in performance.
    
    I guess it also depends on your oponents as was mentionned earlier -
    Jean maybe you are just more skillfull :-)
    
    Paul

    If you buy the rain sealing the sail theory then an old genoa might be
    more porous than a new one... thus the sealing effect on the new one
    wouldn't matter but would on the old one.
    
    Jeff

Not a matter of skills - I often race against the same other boats, and
with one of them I have most of the time a (little) speed disadvantage when
reaching. This was confirmed in the next race ...

I imagine that water can put more tension on old Dacron fibers, getting the 
sails flatter or whatever ... as water does on most fibers and ropes.

Jean

    I'll try that next season - as I can't afford new sails, maybe having a
    crew member regularly dousing the genoa with water will stop me from
    coming in last !
    
    Paul

    
    
    Run a hose with a sprinkler head up the mast and run a pump from
    the water to keep a mist on the sail   (WICKED SMIRK)
    
    								;)
    
    							georgia

    Surely the hose and sprinkler head etc. would be too much wieght to
    hoist up the mast.  To say nothing of the wieght of the water in the
    hose.
    
    Why not just set up a spray on the deck and direct it on the sail ? 
    The savings in stability would be significant.

    Old time (and maybe some modern) sailors used to throw buckets of water
    on the sails when becalmed to 'help them catch the air'.  Why are
    people so amazed that wet sails draw better than dry ones?  This is
    not new information is it?
    
    Jeff
    

    When racing in light air, wet sails are not an advantage - especially
    so for the spinnaker.

    
    Geeze... !!!  i was only kidding about running a hose up the mast.... :)
    
    I mean .. come on.. get a life.   (smirk)
    
                                                 Georgia
    
    PS: besides you could always just race up here in Burlington...
        It always rains on weekend race days...   (Wicked grin)

    I looked up the library I have at home and came across a table on
    sailcloth that show different figures for dry and wet sailcloths for
    both Tenacity (g/Den) and Extension to Break (%). As an example:
    
    Tenacity		Nylon
       Dry		7.0-8.8
       Wet		6.0-7.9
    
    Extension		Nylon
       Dry		16-26
       Wet		19-28
    
    I take this to read that in the case of Nylon the Tenacity (ie sticky -
    maybe the smoothness that air passes over) is low ie the sail is close
    to 12% more slippery when wet and in addition will stretch an
    additional 20%.
    
    There are also differences for Cotton and Glass. 

    But even if that were part of the cause of the improved performance of
    wet sails, why would the "older" sail (presumably a little more baggy
    etc.) start to outperform newer sails.
    
    My guess is that within limits, both sails would benefit (or not) in
    roughly the same manner.  It would seem, for example that if the
    smoothness of one sail is improved by the maximum 12 %, that even if
    other sails only gained say ... 8% because of different
    cloth/construction etc. that the improvement of performance of either
    sail would not be the same as the smoothness (12% or 8%) but rather
    some fraction of it.
    
    The more I think of it the more I like the explanation that has to do
    with attitude in the rain.  
    
    

    I am inclined to agree. The figures I gave are just for interest rather
    than providing an answer.
    
    I never really sail well when it is very rough water as I simply don't
    like the noise of the boat thumping and banging about and yet know that
    some I sail against go really well in those conditions. Its not really
    weight but "mind over matter".

    Interesting comment.
    
    At least with strong winds (certainly in my case) concentration is 100%
    on the wind, and maintaining the boat on course...
    
    The big problem I have in the light "tactical" airs is having to pay
    attention to others as well as trying to keep track of air that is
    barely filling the sails and changing direction all the time...
    
    Paul