Re: [Paddlewise] Waterproof/Breathable no good in saltwater?

>From: Dave Kruger <dkruger_at_pacifier.com>
>One small addendum:  My Kokatat Goretex paddling jacket **seems** to be 
>less
>breathable after the DWR has diminished to the point water no longer beads 
>up
>on the surface -- when the fabric "wets" and is uniformly damp.  There is 
>good
>theory re:  vapor pressure and droplet size to support this impression.  Of
>course, good theory don't make it so.  I'll wager my six seasons of 
>experience
>with this PJ against any theory any day.
>
>--
>Dave Kruger
>Astoria, OR

Here's my understanding of this phenomenon (based on the research and 
writing I do for a outdoor retailer's catalogue, which includes many 
Gore-Tex garments): When the surface face fabric "wets out" due to dirty or 
old DWR (Durable Water Repellency), the evaporative cooling that results 
also cools the inside surface of the garment. There's always vaporous 
perspiration present in the air between the wearer's body and the garment. 
When the inside face of the garment is cooled by the evaporative cooling of 
the surface fabric, more vapour condenses against the inside surface before 
it can "breath out" through the pores. The micropores are not "blocked", but 
just as they don't let liquid rain in, they can't breath out perspiration 
that's condensed to a liquid.

Philip Torrens
N49°16' W123°06'

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