So far all are the wrong shape alas. Due to the shape of hatch openings I'm looking for the long cylindrical shape that is less than 8 inches in diameter. I've had the Sea to Summit ones that assume a drum shape round and fat The Kodisk Purge ones sometimes suck in air and expand during the warm day.
This is an issue if you have ever had the hilarity of a slightly expanded bag that won't come out of a kayak hatch and you are lying on the chickee four feet above tugging on it
Not an issue for a canoeist but we seldom take an open canoe ( we only have one sea canoe) on the ocean or Lake Superior. I'm trying not to gather a wardrobe of dry compression sacks!
We have some (quite old) Seattle Sports compression dry bags and the smaller of them is close to your 8 inch max cylinder.
On the plus side the thick black material is as tough as any dry bag we own. I have never submerged them, but the purge valves have done fine in bilge water.
On the plus and minus side they have four external compression straps, so they can not expand much in the heat. The minus is that the ladder locks on the straps suck it for retrieval when the bag just barely slips through a hatch opening.
I’ve gone the other way; compression stuff bags inside a standard dry bag. We have a fair wardrobe of compression stuff bags in a variety of sizes. I like the ability to segregate something like my cold weather duds (long underwear, fleece, down vest, knit cap) into a single identifiable compression bag the size of a coffee can.
I looked at my most favored and functional compression stuff bags. They do not sport a manufacturer’s tag, but I think they were Sea to Summit, or maybe Surf to Summit (BMO purchase BTW). They are fairly heavy coated nylon, which adds another layer of water resistance, and I have compressed the bejeepers out of them without any strap, stitching or buckle failures (something I cannot say about some cheaper compression bags).
I do find it odd that the design of something as seemingly simple as compression straps, ladder locks and fastex buckles on a compression stuff bag can vary from functionally easy to Oh my gawd what a mess. The compression sack that came with my winter sleeping bag is a nightmare. Or was, I replaced it with one of the better designed S2S bags.
All of our compression dry bags have lengthwise/vertical compression straps with a “cap” end, which does not do much to compress the girth for hatch passage. We do have a couple of stuff bags with compression straps in the other orientation, around the girth, and those tend to fit better inside a tapered dry bag stuffed up in the stems.
When sausaged down those girth compression stuff bags to reduce down to more of a cylindrical shape. Does anyone make a compression dry bag with straps around the girth?
Maybe it is time to DIY some custom sized and shaped dry bags using Seattle Fabrics, and add a purge valve and compression straps.
http://www.seattlefabrics.com/dry_bag.html
