Jan 27, 2012 at 9:10 pm #1284805
I figured I'd start a thread in the packrafting section to document the creation of my inflatable PFD since I'm super stoked about it.
The project started off as a hybrid air/foam PFD, but I've now shifted directions and I'm making purely an air PFD. I decided filling the air chambers about 1/3 to 1/2 full of foam would significantly increase the bulk and weight, while still sucking at being a PFD since it would be below the minimum amount of float I really need. Accordingly, this PFD is now an ultralight inflatable PFD for moderate wilderness use, and I'll use a more robust foam PFD if I ever start creek boating locally.
All materials to date have been ordered from QuestOutfitters.com
Stage 1 – Making the Vest
Using 2.2oz 70D nylon, I set about making a basic vest. I traced the outline (minus the sleeves) of a shirt that fits well onto my fabric. Then I cut that out and make a duplicate so I had two halves. I then sewed them together using flat felled seams.
Then I made the 'front' more of a front by adding a 'V' to the neck line and I cut it open down the front. I then enlarged the sleeve holes, mostly towards the front and bottom (as you can see in the first pic), so that there is lots of room to paddle without interference. Once I was happy with everything, I sewed on the edging from Quest. Unfortunately I didn't order quite enough (3 yards) so I'll have to finish the edging later.
Stage 2 – The Back Chamber
With the vest made, the next order of business was to create the 3 air chambers (one upper back, two on chest) needed to float. I decided about 22 lbs of float (10 back, 12 chest) would be a decent amount, since I don't plan to run crazy white water with this.
I sat in my pack raft and figured out where I could position the air chamber that wouldn't interfere with my use of the back rest. I did think about eliminating the raft backrest and incorporating an air chamber into the vest instead, but I didn't want the floatation getting too low down my body because I want to make sure I float head up.
I deciding on a back chamber of 12" (wide), 9" (tall) and 2.5" thick. This gives me a total of 270 cubic inches and 9.7 lbs of float. I suspect in reality because the chamber will bulge a bit away from a perfect rectangle, I'll get a bit more float than this.
To make the chamber, I used 70D heat sealable nylon (from Quest). I didn't want to bond to equal halves together like is normally done to create sleeping pads and pillows, because I wanted a non-symetrical shape that would sit nicely against my back. This is hard to explain, so I'll let the photos do the talking:
Flat side, which will get sewn to the vest around the 3/4" bonded perimeter:
I'm super stoked about this air chamber. I still need to add the valve. It's going where my fingers are in the first picture. By putting it in the corner seam, I leave the perimeter seam intact so I can sew it to the vest all the way around.
As a side bonus, this is going to make an amazing pillow.
I haven't totally determined how I'm going to sew it to the vest yet, but it shouldn't be too hard. I might cut a hole and reinforce the edge before sewing it to the chamber, or I might just sew it on.
The work continues…Jan 27, 2012 at 9:14 pm #1830783
Oh…the chamber weighs 42g (1.48oz) and the valve will add ~0.2oz…for a 1.7oz total.
The vest is 44g (1.55oz) but it still needs another 4g in edging and then the webbing and buckles (1oz?).
Add in ~2.5oz for the two smaller chambers on the front, and I think I'm going to wind up around 7oz.Jan 28, 2012 at 2:52 am #1830820
Very cool Dan. IIRC, my old SOSpenders Scout Life Vest weighed around 9 oz after taking off the autoinflate parts.Jan 28, 2012 at 9:08 am #1830867
I'll be happy as long as I can keep mine the same or lighter than that, since my vest is going to be quite a bit more featured and comfortable (hopefully).
– The upper buckle is going to have an integrated whistle
– Two pockets on front below the air chambers. One for fishing lure box and the other for a knife, snacks, sun screen etc.
– Rear air chamber doubles as a nicely sized pillow.Jan 28, 2012 at 1:37 pm #1830949
@hamericaLocale: Northern Virginia
Looks great Dan! I really need to learn how to sew. How do you plan on testing this thing when it is done?Jan 28, 2012 at 1:44 pm #1830952
@biointegraLocale: Puget Sound
How else?Jan 28, 2012 at 1:47 pm #1830953
@biointegraLocale: Puget Sound
Sorry for cluttering the thread, I couldn't resist.
Thanks for sharing this project, Dan. The photos are very helpful and the weight to feature ratio looks great!
I have considered a similar pursuit, but want to incorporate some solid foam for margin, as your original idea, if I can get it light enough. Your process is thought provoking.Jan 28, 2012 at 3:40 pm #1830988
The difficulty with designing an inflatable or hybrid PFD is that partly comes down to safety vs. weight, so you need to choose a compromise that works with your intended use and risk tolerance. Even with a foam PFD, you face that compromise somewhat (ie. how much foam to put in?).
One question I've been asking myself is: "What would happen if it popped?"
It seems to me that if any one chamber popped, I would still be okay (with 'okay' defined as floating generally head up). If the back chamber popped, I'd likely float chest up, so hopefully my face would be out of the water (but maybe not). If one of the front chambers popped, I'd still probably float upright but with a tilt. It's good I will have two front chambers. The real danger would be if both front chambers popped (and not the back one). Then I'd be floating face down. I think I'm okay with this risk, since popping two separate air chambers in one swim seems quite unlikely, and even if it did I would still okay (I could clip out) unless I was knocked out too….so 3 bad things would have to happen at once for me to be in serious trouble.
With separate valves for each chamber, I will be able to test this out and see if it floats as I'm theorizing. If my PFD can indeed sustain any one puncture and still make a positive contribution to my floating head up, then I'm okay with that risk situation. However if I single puncture results in me floating face down, then I'm not sure I want that risk. If this ends up being the case, then I think I would link the three air chambers together (hose) so that if one pops, then the whole thing goes flat. Since I don't on any crazy creek boating, I'm okay with this risk. I'm going to keep it as 3 chambers for now, as having 2 out of 3 seems safer than having 0 out of 3, but I'll test that out when I can.Jan 28, 2012 at 3:43 pm #1830989
" How do you plan on testing this thing when it is done?"
Good question….the lakes are darn cold around here right now. Ideally I'd take it to the local swimming pool, but it's a pretty busy place and I'd look pretty ridiculous. I suppose it's either that, or wait until spring…..or poach someone's hot tub.Jan 28, 2012 at 5:36 pm #1831039
@hamericaLocale: Northern Virginia
Since when did anyone on this site care about looking ridiculous ;)Jan 30, 2012 at 6:22 pm #1831952
@davecLocale: Crown of the Continent
Looks awesome Dan. My thoughts on the safety of three chambers matches with yours pretty well. Realistically, a PFD like yours would suit the vast majority of my packrafting just fine. I'm more interested in having something much smaller to pack than the weight savings (though saving ~10 oz is nice too).
Make sure the front chambers don't mess with the lap pillow.Jan 30, 2012 at 6:30 pm #1831958
@cameronLocale: Midland, Texas
Very cool project. I wonder if you could turn this into a side business if it works well. Liablity issues would be something to think about though.Jan 30, 2012 at 7:44 pm #1832005
Things are coming along pretty good.
I got the back chamber installed. I put it on there with 3 lines of sewing and then I zig-zagged over top of the inner and outer stitching to really make it bomber:
I designed the back chamber so it's just high enough that it doesn't interfere with the pack raft backrest. As long as you don't inflate it too firm, you can't tell you're wearing it. It could be firmer than this pic though. Kinda funny looking…but effective.
I started putting the buckles on, but had to stop since I don't have all the edging in place yet. I've now decided I'm going to go with 3 buckles instead of 2, so one more will be added in the middle so it doesn't splay open when seated:
I made the front two chambers today, after redesigning them about 4 times. I'm still not sure they're going to be perfect, but I'm keep working away until they are. Tomorrow the valve glue will be dry and then I'll tape them to in place and see how it works before actually sewing.
As it sits now, I've got 9.7 lbs of float in the back and 11 lbs in the front. With the front flotation also a bit lower down, it should give me a nice lean back.
"I wonder if you could turn this into a side business if it works well."
Unlike most of the projects I've made (ie. cuben fly), I probably would make a couple more of these if people really wanted. Definitely not a permanently business though, as I get tired of making the same stuff pretty quickly.Jan 30, 2012 at 7:52 pm #1832010
Oh…with all three chambers and two buckles, this PFD is at 6.51oz. The rest of the edging (5g) and third buckle (8g) will take me to 7oz. I'll probably add another 0.5oz in pockets too. So I'm estimating 7.5oz finished weight.Jan 31, 2012 at 4:13 am #1832112
Very cool! The estimated finished weight is awesome.
Not to be a negative nancy, but is anyone concerned with the legality of MYOG life vests? I only ask this because while packrafting Isle Royale, we were mildly harassed by a ranger who threatened to terminate our trip because we were in "glorified pool toys" (our alpacka rafts). He lamented that the boats didn't have some sort of coast guard rating. Luckily our inflatable PFDs were coast guard approved because he thoroughly inspected those too.
(full details coming soon hopefully)
Maybe you'll be in more remote places. Just a thought.
But great work! :)Jan 31, 2012 at 8:08 am #1832164
Yes, you have to take the risk of getting ticketed if wearing a myog vest.Jan 31, 2012 at 1:08 pm #1832301
Perhaps the rules are different up here in Canada….I'm not entirely sure what the rules are because they don't seem to be enforced. I know a lot of people raft the mellower creeks/rivers around here without PFDs at all, so I'm not too worried about a MYOG PFDl. I'd only be concerned if I was in a motor boat.
Also, the funding for BC Parks has been cut back so much that I've never seen a ranger ever….so yeah I'll chance a $75 fee.Jan 31, 2012 at 1:21 pm #1832310
Just as a point of conversation, I believe it is a legal requirement to carry a certified PFD for packrafts, canoes, bellyboats, etc. in Canada. See http://www.tc.gc.ca/publications/en/tp511/pdf/hr/tp511e.pdf pages 22-23
"These requirements do not apply to inflatable self-propelled water toys
because these toys are not designed for use in open water. If you do choose
to operate these toys in open water, they will be treated as pleasure craft and
subject to the same strict rules."
Now, note the language says that "one PFD per person", and does not specific whether that PFD needs to be worn or not. Also, it does not say at what point a small body of water, such as a creek, becomes "open water".
Legality aside, I agree that the park services in BC are so underfunded and understaffed that I think the chances of being stopped are rare. In some instances you'd be more likely to be stopped by DFO officers, and I am not sure if they would inspect life jackets all that closely.
If anyone else has a more definitive sources for legal requirements for small self-propelled vessels in Canada I would be interested in learning the exact rules and definitions.Jan 31, 2012 at 1:28 pm #1832313
@davidinkenaiLocale: North Woods. Far North.
In the US, it could come up if you are on "Navigable Waters" and subject to Coast Guard inspection. Then lacking any of your required safety gear (signaling devices, lighting at night, PFDs, etc) could cause an issue as could design issues with the boat. Some states have requirements for children to be wearing PFDs as opposed to them just being on board. Required gear varies greatly with boat length, power/sail/paddle.
US National Parks sometimes have their own regulations and inspections for boats. GCNP comes to mind as being especially detailed with your hand sanitizer system inspected beforehand, your pottie weighed afterwards and certainly high-floatation PFDs being required to be worn at all times while on the water within the park.
Any PFD you wear (MYOG, factory, whatever) is better than the most approved PFD that you're not wearing. The biggest determiner of survival in a small plane ditching in Alaska is if you went out of the aircraft with a PFD on. You'll be incapable of helping yourself within minutes, but if you're bobbing around with your head above water 30-40 minutes later, the Coast Guard might save you.
If you don't get off a Mayday, a helpful Q to ask is, "Okay, I swam / washed up on shore – now what?" Consider that you might be in your paddling clothes, with your PFD and NOTHING ELSE. When I work for the USFS, they issue inflatable PFDs in blaze orange that are like a photographer's vest with little pockets all over. There's a mirror, space blanket, whistle, leatherman, cord, power bar(?) – they did a pretty good job of putting in the stuff you'd most want. I've since converted by factory PFDs with little zippered organizer pouches to hold that stuff. Since it's "modified" it might not pass an inspection but I can't imagine being led away in handcuffs because I have survival gear and SPOT in my PFD. At least not up here.Jan 31, 2012 at 7:38 pm #1832530
I'll take one. I'm 6'0, 155lbs.Jan 31, 2012 at 9:30 pm #1832582
Wait a few days and see how the front turns out. I'm still not sure about it.
Getting enough float on the front isn't hard, I just want designed so it doesn't interfere with the spray deck waist. I think I'm going to have to go with larger but thinner bladders, so they are only 1-1.5" thick. Once you get to 2-2.5" I start to get worried about how well the spray skirt wraps around.Feb 3, 2012 at 4:42 pm #1834090
I scrapped the front air chambers I made a couple days ago and made two more that I'm finally pleased with. I got those made and sewn on today and I'm quite happy. You can't really tell in the picture, but the top side of the air chambers is sloped at a 45 degree.
Right now the PFD tips the scales at 6.71oz and it's actually only going to get lighter. I'm going to cut off the bottom 4" or so of the vest that hangs below the front air chambers and just leave an inch, since there really is no purpose for this material. That'll probably cut off 1/2oz and then I'll add a bit back on by adding a pocket above each front chamber, so my final estimated weight is 6.5oz. I'm heading out to a backcountry cabin for the weekend, so I plan to finish it on Monday or Tues.
If I ever make more vests, they'd wind up a bit lighter still because there is no need for 3 buckles. Had I placed my middle buckle a few inches higher at the top of the chambers, I wouldn't need the top one. Another way to save a bunch of weight would be to use lighter heat sealable material on the inside of the air chambers (the part that goes against the vest), but I'm not sure where to get that stuff. The air chambers are most of the weight on this thing (ie. 2/3rds).
The front chambers are really soft in this pic since the valves are still drying. You do want them a little soft though so they wrap around your body instead of being rigid.
Notice the line across the right chamber….I was really getting low on heat sealable material after 4 attempts on the front chambers, so I had to attach two pieces together to create a larger piece before I could cut this panel.Feb 3, 2012 at 4:48 pm #1834095
@cameronLocale: Midland, Texas
Very interesting to follow your project, glad its coming together.
Here's another idea for those who don't want a lighter PFD but don't want to go the inflatable route. How about a PFD with lighter fabric (all that I've seen are heavy duty) and removable foam? The lighter shell would save some weight and the removable foam could be packed a lot more efficiently so it wouldn't take up as much room.Feb 3, 2012 at 4:51 pm #1834097
Just like on Letterman, I'd love to see you, in this thing, in some whitewater.
I'm sure it works to some degree, but I'm really curious to see how well. Let's see some test videos!
Also, in terms of legality what immediately came to my mind is that selling a PFD without having it approved may leave you liable. Not that any BPLers would do that, right?Feb 3, 2012 at 5:09 pm #1834104
"selling a PFD without having it approved may leave you liable."
Yeah…it could be the 'desert vest' designed for carrying extra water on long dry stretches of trail. Just take a mouthful of water and blow it into the valve.
"How about a PFD with lighter fabric (all that I've seen are heavy duty) and removable foam?"
I think this could work really good. Fabric can be really light, so the hard part could just be finding the best foam. A 70D nylon vest with lots of chambers for foam would be no more than 2-3oz. Also, with removable foam bits you could alternatively substitute in air filled platypus bottles for UL trips on mellow water.
"I'm really curious to see how well [it floats]"
Yeah me too….hopefully it's not an utter failure and I have to start over. There's a lake on my street with about 10' x 10' of open water where a stream enters. I could jump in there :) Honestly, I'm not sure when I'm going to test it. The lakes are awfully cold and frozen, and the local pool charges $10 to get in, which is a lot to pay just to go look goofy in front of everyone.
You must be logged in to reply to this topic.