MYOG Inflatable PFD – Progress Journal

[Tad Englund]

Dan, great job.
Could you nave made pockets for the air chambers to fit in instead of sewing them in- how much extra weight do you think it would add? My thinking is if you get a leak in a chamber you could just swap out a good one.

I thought about this because of your comment about inflation and fitting close to the body. My thought was to make separate tubes but that would be inefficient- too many valves. Then I thought maybe seal up the chambers almost all the way, just a little opening at each end (like a cheap blow up pool mattress). You could make the outside larger then the inside causing it to curve when inflated. Being in a sleeve/pocket they might allow for a better fit.

You might be able to get a lighter weight heat sealable fabric at Seattle Fabrics. I saw some in there this summer when I was getting fabric for some lightweight dry bags. It was a little too lightweight for me to use for kayaking. But now I wish I would have picked some up.

[Dan @ Durston Gear]

Making pockets for the air chambers instead of sewing them on wouldn't take that much fabric. Maybe an ounce, plus whatever other weight you add in terms of zippers or snaps…so 2-3oz if you had a lot of hardware.

However, making the air chambers is by far the hardest and time consuming part of this (getting all the measurements draw on the material, cutting it, adding baffles and heat sealing etc). So if you actually did this you'd probably want to use the same chamber for all 3-4 spots instead of unique chambers, so you'd only need to carry one spare. Creating 3 unique spares would add a lot of work.

The biggest challenge with a PFD seems to be getting enough inflation on the front of your torso. It's easy to add tons of float to the back because it's out of the way. With the front though, you need to get quite a bit of float out of a relatively small area. I couldn't make the front air chambers any lower, because when you're sitting down you don't want them hitting your legs and being shoved up. I could have made them a little taller, but it starts to get interfere with the movement of your arms and the vest is narrowing quite a bit so there's not that much room anyways.

My point is just that if you didn't use baffles and just mostly used 'sewn thru' construction (but heat sealed) then it would wrap around your body better but you'd have a hard time getting enough air volume. Even as it is, I'm nervous about how much I have on the front. I have about 8 lbs of float on the front and 9.7 on the back. It might float alright, or I'm might need to partially deflate the back chamber to float on a nice lay back position.

One approach that would work well would be to NOT have the closure up the front, as it takes up valuable space. If you made a vest that was a pull over and then attached at the sides, you'd have an intact front area to work with. With this, you might be able to use a 'sewn thru' construction technique and still get enough air volume.

The front pads on this are 1.5" thick. Originally I made chambers that were 2.5" thick but it was too bulky. I went to 1.5" thick and maybe them a little larger. It actually feels quite good. It's fine if the chambers are firmly inflated, and if you back it off 10% then you don't even notice they're there.

[P. Larson]

Dan, noticed you put a gear list up for the Bob. I'll see you there bud.

[Rob E]

Hi Dan,

Really like your progress, excited to see how you do in a float test on the water.

I like your idea of not having separate front/rear inflation bladders so that you don't have to carry multiple spares.

If the weight/cost of a valve isn't that much, what about a modular system in which you have several different inflation "tubes" that you can stuff places. I am thinking cylindrical inflation tubes, something like 2-3 inches in diameter and 6-8" in length. You could then place a few where they are needed. say 3 or 4 in your back, and 2 in each front side. There is redundancy because if one of the chambers pops you don't loose the entire inflation on that quarter. This way you have redundancy and can carry the same size spare. Also, for easier trips, warm weather on still water, you can reduce the number of chambers you use, and for say, white-water in colder weather, you could stuff more chambers in there.

Anyway, just a thought, I haven't worked through all the implications, or concluded as to whether this is a good or bad idea. I think a lot hinges on the cost/weight/hassle of the valves.

Cheers

[Dan @ Durston Gear]

"…noticed you put a gear list up for the Bob. I'll see you there bud."

Yeah I'm pretty sure I can make it. Work is still a bit of an unknown but it looks good.

I whipped up that list pretty quick but it's a likely strategy that I may take. Obviously I have a pack raft and if I went that route my list would be really different. I haven't really planned my route yet (waiting on maps which are in the mail), so that will affect gear decisions a lot.

"what about a modular system in which you have several different inflation "tubes" that you can stuff places."
I think there would be a place for a design like this. If I was planning on running riskier water where there's a chance I get chewed up pretty good then I'd want more redundancy in the chambers. For me, I plan on mostly running class 2-3 in the wilderness and I feel pretty comfortable with risk I'm taking on. If I was thinking about class 4 water then I'd water additional precautions. I do want to get into some class 4 in local waters, but I'd probably just buy a cheap foam inflatable for this.

With regards to the design, perhaps a mix of tubes/chambers and Platypus bottles would work well, because you'd add redundancy and use gear you're already carrying. You could also make a PFD with a few (3?) non-removable chambers, but then it would also have smaller pockets for 1L or 500ml platy bottles that you could stuff in there too for gnarlier waters.

It wouldn't add that much weight to have more chambers. You're looking about maybe 0.3 or 0.4oz for a valve. You wouldn't want to have ten, but 6 instead of 3 would only be an extra ounce, plus likely a bit more fabric for the separate chambers.

[P. Larson]

I've been doing some looking around (I have the NatGeo TOPO program for Montana) and it seems that you could do without a pack raft for the whole trip. Most of the rivers seem to flow either north or far south of the finish point.

I also noticed you are bringing a shelter and a sleeping bag. I don't think I'm packing that. Hehehe.

[Dan @ Durston Gear]

I trimmed the excess fabric off the bottom that wasn't serving a purpose. The air chambers needed to be as high as they are so they don't hit your lap when sitting.

PFD is now 6.4oz. It's getting two pockets (one above each front chamber) and then prototype 1 is complete.

The front chambers feel good when wearing it. They don't feel too bulky

If I ever make a V2, it would have two buckles instead of 3, likely some refinements to the back air chamber shape (it's probably a bit big) and possibly lighter through the use of 30D heat sealable nylon the inner sides of the chambers.

[Colin Krusor]

My thought when I read through this thread was "How could this and a sleeping pad be integrated?" I know that you mentioned that you plan to use this PFD as a pillow. I was just thinking that it might be more volume than you really need for a pillow, and you could save some weight by combining some of that extra volume with an MYOG sleeping pad.

[Dan @ Durston Gear]

I'm not sure you could use it as a torso pad, but perhaps you could combine it with a torso pad to make a full length one.

This PFD is essentially finished. I ended up changing how it opens. I sewed the front together and removed the buckles to get the air chambers closer to together (and to the front) to improve floating position and get them a bit further away from my arms. I cut a slit from one of the air holes down to the bottom, which is how it is put on now. It uses a few clips to close up, and then I added some cord and LineLoc3's around the back of the vest so it can be snugged up nicely.

I'll try to post updated pics sometime. I've been away hiking/travelling/working a lot lately.

[Mike W]

Dan –

I'd be interested in seeing photos of the vest in action if/when you get up the nerve to pool test it.

I have a variety of floatation devices that I've acquired over the years and none are perfect. I really like the idea of a custom solution. The "official" regulations hear in Canada requires a floatation device to keep you afloat "face up" while unconscious. While I understand why that is a desireable requirement, what it actually accomplishes is a life vest design that is so uncomfortable to wear that nobody wears their vests. If you are under 16 (in Canada) you have to wear a certified floatation device while on the water. If you are over sixteen you have to have an approved life saving vest in your water craft.

Where it gets sketchy is in things like float tubes (for fishing). You are actually required to have a vest but most don't and as you said, who is checking on provincial waters. Some of our lakes are patrolled by the local police but I've never been challenged regarding a life vest in any of my water craft in freshwater. Definitely a different story in salt water where I am constantly challenged to produce my saftey equipment (and even thanked for wearing my vest!).

I have a fishing vest that incorporates an inflatable bladder (CO2 rip cord type) that is certified and might be an option if deconstructed and rebuild to you design.

I also have a device that was build as a prototype that failed certification so the manufacturer couldn't produce them. It's a very small (flat) package that clips to my belt loop and uses a rip cord to inflate a large "log". Easy to carry and as long as I'm conscious, would do a great job (as long as you can hang onto the inflated log). This is the device that I use the most as it's small and out of the way but accessible.

I also have a canoeing vest that is trimmed down in size and allows free arm movement and is really comfortable to wear however, it doesn't float me "face up" so technically not legal.

Keep us posted when you do your final testing. Great project!

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