Thanks for your experience with valves used in drybags for sea
kayaking (although I will also use these homemade, small drybags for
backpacking, and bicycle touring, too).

The valve at NRS Float Bag Valve
http://www.nrscatalog.com/product.asp?pfid=3875 is most likely the
lowest cost, although I doubt I could get your price of 8 for $1.00

Those drysuit valves are kinda big and likely a lot more than the
$0.30 for the NRS valve. A quick google scan on the drysuit valves
yields prices between $50 and $100!!

And yes, the drysuit dump cuff valves are relatively expensive.
The Apeks Drysuit Cuff dump is as of October 16, 2003 11.75 GBP
(United Kingdom Pounds) or about US $20, shipping not included as
listed
at http://www.divebooty.co.uk/equipment...ls.asp?pid=276,
Description:
Totally free from maintenance and requires no adjustment. Designed to
fit in the suit cuff and allows venting air to escape from the suit by
simply raising the arm for others who may search for this.
Merchant: Simply Scuba
Manufacturer: Apeks
Category: Drysuit Accessories
Model: Drysuit Cuff dump
Price: £11.75 GBP Convert
Shipping: See Site


Other valves that I am considering (as I am trying to avoid using
tubes)
although I like your ideal of
I'm using them with short tubes and am planning to use a little
flap to tuck them in. For a tapered drybag, I'm just going
to put it on the end sticking out minimally

and may use it. I have these type of valves on other floatation bags.

I found at the following web pages. These valves may have the issue
you mentioned about releasing when packed into tight spots. I would
need to modify the string like release if I were to use these valves.

There may be another type of valve, but I can't think of one. Those

BTW, the BCD valves release relatively easily. If you stuff
the drybag into a tight spot and the cord is slightly tugged in the
process, it will stay open.

And I strongly prefer to avoid pulling out a damp or wet sleeping bag
along with damp or wet clothing out of a drybag with a OPV or purge
valve that released.

At www.gmcscuba.com (Global MFG. Corpo, 1829 S. 68 Street, West Allis,
Wisconsin 53214, U.S.A. in my part of the world, makes a purge valve
for lift bags. It is listed on page 7 on their online catalog, in the
communication products and support gear section, item number 57030
Purge valve Purge Valve for Lift Bags. These are sold at local
scuba shops in the Minneapolis, Minnesota, U.S.A. area. I will look
at these valves.

At www.underwaterfloation.com/drybags.htm, there are Prolift over
pressure valves used in liftbags. Prolift Over Pressure Valves are
available in 2 styles. The two piece black screw type is used on our
smaller liftbags and requires no special tooling for installation.
The large white PVC Valve is used on larger liftbags and requires a 1
1/2" flange to be installed.
OPVBLK - Over Pressure Valve Black $9.00
OPVWHT - Over Pressure Valve White $12.00
And liftbags could make the world's largest sponsons, making a kayak
unsinkable (just kidding .

I assume these purge and over pressure valves are similar to BCD
valves, although I do not have a BCD (just a simple kayaker, no scuba
experience).


I have spent far more time looking at valves than I initially planned
(and looking at scuba related gear in the process).

Scott