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Hi
just an idea I thought I’d share to see if anyone had tried this out….
instead of fitting an airtight zipper, I was thinking of installing an opening either on the side or a seam of the packraft, with a tube of fabric (basically two rectangles sealed to each other on two opposite sides to form a tube, then seal one open end of the tube to the packraft, and the other end left open). The tube could then be rolled up and secured with a clip or velcrose, in the same way that waterproof bags with rolltop enclosures work. This would be cheaper, possibly lighter, and maintenance free, compared to an airtight zipper.
Just an idea at the moment. I’ll give an update if I can get something to work, but just wondering what your thoughts were?
Jamie.
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Hi came across this thread on the forum and these things https://netherlands.husse.com/clip-for-husse-dry-food-bag#footer_box4
Seem a good idea. Only thing I don’t like is that it’s not attached and losing it really is not an option… Unless you like swimming.
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I’m not planning on buying one myself. In fact I’ll probably order the ultralight kit sometime soon here. Just the sheer joy of making my own raft again after making a V3 last year will be worth it.
I now see the post by Apope in his topic on spray decks on his Rapid Rafts, however and these rafts seem to use the exact same system and have been around a little longer. I found some reviews on Reddit and Unchartered’s site.
Apparently the closure is not completely airtight, but when closed properly you can compensate by inflating it by mouth every now and then. The bigger problem seems to be that the rolled part doesn’t absorb shocks very well and therefore is very prone to punctures.
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The new packraft by Anfibio uses a roll top closure for lugage storage instead of a zipper. They say they use “special technology” and claim there’s no loss of pressure.
https://www.packrafting-store.de/New/Anfibio-Nano-RTC::939.html
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Someone must have read your post :-). This feature is now available in the Nortik Duo Expedition packraft. The raft has two internal bags which are sealed with watertproof zippers. I guess that the internal pressure on the bags keeps air and water out. Found no reviews on the performance, but here’s a pic: https://www.faltboot.de/fileadmin/_processed_/1/3/csm_nortik_raft_Tasche_integriert_6b109150e1.jpg
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The Neo Air has a short internal tube made of a thin plastic film, which is bonded to the rim of the outer tube opening that is part of the shell. The internal tube acts as a valve (similar to the type of valve on some disposable inflatable pillows), whereby the internal pressure causes the valve to close up, thus providing an airtight seal. Maybe this is the way to go – seal a thin TPU tube (2 rectangular strips bonded along the two longer sides) around the rim of the roll-top opening and let this tube hang inside the packraft acting as a valve. Obviously this works for the Thermorest, and I have had success with this type of valve on an air bladder. Definitely worth giving a go. I’ll report back once I’ve had a go.
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Aha – have just found a youtube video showing what you describe. So I guess this inner valve would also be ‘sticky and cling to itself’ as you mentioned before on your own gear. I’m dead keen on finding a replacement for zippers if possible, and was just thinking about making up a test rig of a bladder representing the hull with a ‘tube’ thing in the seam. It would look quite like the neoair inner tube, but 75 or so cm long and high enough to get say 5 rolls at 30mm each. And then velcroed down to the hull with a flap velcroed over the whole thing to tie both sides of the hull together. The cargo zips I have now are 72cm, but the one on my MRS raft always niggles at me – it’s too easily damaged and means that the raft is no longer field repairable.
I’ll postpone making this until you’ve tested yours, if that’s not too cheeky:) I now see that this inner valve seals by virtue of using pressure (rather than fighting it), and having one hanging down as you say could well be key.
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<p style=”text-align: left;”>Thanks – I take your point about the difficulty in getting an airtight seal. I have made air bladders out of TPU film (rather than TPU coated nylon). The material is stretchy and kind of clings to itself, so it wasn’t difficult to create an airtight seal. Maybe I’ll try and bond a tube of this stuff to the TPU coating and see if it works. For a 50cm opening, the zip is probably the way to go, but this could be useful for a narrower opening just to provide access for leaks and repairs.</p>
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I was thinking of something along the same lines, but all the roll-top drybags I’ve owned aren’t airtight – they keep water out, but if you sit on them they slowly deflate – so I was thinking of a closure more like the slide-on clips found on hydration bags (Camelback, etc.). I don’t know how to make one of those though, and it would have to be quite long to be useful (at least 50 cm), so I put the idea aside. Maybe someone else can think of a better solution though.
Cheers!
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I made an air pillow once with a roll top, thinking that a dozen rolls ought to keep air in. It stayed up for a couple of hours but was always flat in the morning.
Thermarest have a new ‘speedvalve’ on one model Neoair. This looks like a roll top about 20cm wide. Towards the end of the video they say ‘tuck the black inner valve all the way inside’ before rolling it 7 times to close. The camera doesn’t show this ‘inner valve’. Has anyone seen one? It may be key to keeping it airtight.
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