Re: [Paddlewise] Do your dry bags deflate air

From: Shawn Baker <shawnkayak_at_yahoo.com>
Date: Fri, 21 Feb 2003 13:05:00 -0800 (PST)
Hello Ashton and Leska,

allaha <allaha_at_earthlink.net> wrot:                    
> Got Seattle Sports brand, Hydro Venture Glacier Clear Dry Bags, small
& medium sizes. Filled them about 1/3 with emergency fleece clothing in

case of dunking, rest of space air. About 1/2 hour after sealing, air
has deflated _at_ 50%. Bags limp squishy soft --

It's more common practice to put something soft (like your fleece) on
top of other gear in a dry bag so that all extra air can be squeezed
out while sealing.

Thought being that if the bag is compressed, air will try to squeeze
out (out the mouth of the bag) and anywhere air can get out, water can
get in.  If all air is already squeezed out, no water will get in, as
there won't be any spots in the rolled seal that are "opened" by the
passing air.

>Is this quick air deflation normal? ???

Not really, but they're not really made to hold pressurized air.

>Bought them for dual purpose: floatation and keeping gear dry.

Your average dry bag won't hold enough air to work as adequate
flotation.  Not that gear in a dry bag won't displace water--it's just
that you should try to fill all your floodable space with a _float_
bag.

Keep using the drybag--a float bag will fill in around your drybags.

Consider that a stack of camping cookpots has 0 buoyancy value.  Put
the same pots and pans in a drybag, and you probably have 10 lbs. of
buoyancy (even with the air squeezed out of the drybag around them). 
Same with your fleece, wet in the kayak, it has nearly no buoyancy (or
warmth!), but in a drybag, 2 or 3 lbs.

>Wondering if the brand is bad 

They're a reputable manufacturer.  Make sure you're sealing them
correctly.  Only fill the bag 2/3-3/4 full, and make sure you get the
closure strips to match flat (your seal is in the vinyl-to-vinyl
contact in the mouth of the bag.  Make sure you get at least 3 folds. 
Once it's rolled and clipped, squeeze the bag--do you hear air
whooshing out?  If not, you have a good seal.  If you slowly lose air
after a few hours, you probably won't pick up much water at all in the
event of a dunking, either.

>If air seeps out so easily, does that mean water will seep (or
flood!?) 
IN just as easily?

Sort of--like I mentioned before, if it rushes out easily, water can
rush in easily.  If a tiny bit of air seeps out, a tinier bit of water
will seep out--air will travel up and down through the rolls in the bag
to come out.  Water is more constrained by gravity--it might get into
the bottom of the first roll, but won't as easily travel upward to the
top of that roll, or the next, or the next.  Maybe a teensy bit by
capillary action, but not enough to soak your dry things.

Enough of this lengthy diatribe on dry bags.  Consider buying float
bags.

It's pretty cold water out--make sure you're dressed for immersion, not
the air temperature.  Unless it's the cold water that has kept your new
Zydecos off the water, in which case, smart thinking!!

Safe paddling, and enjoy!!!

Shawn

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Received on Fri Feb 21 2003 - 13:05:05 PST

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