Has anyone made an interchangeable underquilt?

[Tendertoe]

I agree with the added weight part but the hassle would only be seasonal when you change the tubes. At the very least it would save from hanging 3 full UQ's in storage.

+1

Plus I was thinking that if someone would end up manufacturing these, the cost may be less to purchase a shell and 2 sets of tubes rather than 2 complete UQ's (considering it would probably be easier/cheaper to make a set of tubes compared to a complete UQ).

As far as weight, some folks would take the weight penalty if the price was right - 2 quilts for the price of 1.5...

[Fibby]

I was going to agree but thought about this. Make a light sewn through synthetic summer weight inner layer with the baffles hung below the synthetic layer so the tubes hang between the synthetic and the bottom cover. That gives min and max insulation while the synthetic layer adds a bit of body. Probably need flaps over both ends to keep the tubes in place and strings on the tubes to pull them through. Button the flaps like a duvet cover instead of velcro. More repairable and reliable. If the tubes try to bunch lengthwise add a button at each end of each tube to put a couple of wraps of the pull string around.

You could pull the strings through the loop as well and save the weight of the buttons. The strings could be detachable since you only need them for changing the tubes. Or a button on the tube and a loop at the end of each baffle and button through the loop to secure the tubes. I can't wait to try this. The first try might be a little sloppy but I'll take pics.

And I won't be using down for first the mock up anyway. I can always add down tubes later.

[Fibby]

Perhaps I'm just not visualizing well, but wouldn't there be issues with either:

A.)gaps between the tubes and the hammock when using low-loft ones for summer

or

B.)compression of the down in the winter tubes,

depending on the underquilt attachment points?

Or, maybe, two sets of attachment points could be used? One that is at the very top edge of the quilt for the high-loft winter tubes, and one that is in the middle of the vertical dimension of the quilt for summer/3-season use? Would that solve the gap/insulation compression issue?

Or, maybe even better, a single summer/3-season quilt that then has omni-tape attachment points on the bottom for a winter add-on quilt shell as opposed to pre-set tubes?

I am planning on making the baffles big enough for the winter tubes. Thinking... yeah maybe a summer quilt base layer would work better (thanks Nothermark for the idea).

[gargoyle]

Perhaps I'm just not visualizing well, but wouldn't there be issues with either:

A.)gaps between the tubes and the hammock when using low-loft ones for summer

or

B.)compression of the down in the winter tubes,

Gaps and fit would be a problem with the tube system, IMO.

Another solution may be stackable/modular thin underquilts.
Say each quilt is only 1" loft. And each quilt would be differentially cut a little larger than the other to offset any compression, and have matching tieouts.
A 1" loft quilt for summer.
Add a second quilt for 2" of total loft, for spring and fall.
Add a third layer for winter. That would 3" of total loft, plus the additional fabric layers.
The extra layers will add weight, but so would tubes. But you'd be gauranteed a tight fit. The trapped air between the layers of fabric may improve the quilts rating? Or allow heat to escape?

Mac did something similar with the IX quilt

[goatnuck]

This is a very cool idea, but I'm not convinced of the value in it. You still need to purchase enough down to make tubes for all three seasons and store those that are not in use. So you don't save much money (fabric is relatively cheap). You don't save on storage space either. I guess one benefit, aside from the coolness factor, is that you only have to sew one quilt body.

In order for the down tubes to properly fill the chambers in the hammock body, the external dimensions of the tubes will need to be larger than the dimensions of the chambers in the quilt body; this would hopefully allow the down to loft into all the edges and corners in order to avoid cold spots.

[BlackGoat]

I don't believe I have seen an interchangeable quilt with down. However, if you do some searching you will find that this concept has been explored quite successfully by the synthetic insulation crowd (Climashield XP/Insultex). I made one with XP, and I believe that WB also had a Climashield prototype version he was selling years back. I believe the TTTG orca has the option of being layered .

To me, there is little value to use down for this application, since it will require fabric for each tube and you will have a lot of tweaking to make sure your tubes are the not being compressed or bunching. I am thinking it can definitely be done, but it will have a steep learning curve. With Climashield/Insultex, you are only paying for weight of the insulation, since it holds itself together.


Like to see what you come up with.

BG

[wwk10]

I'm not convinced yet, but I encourage the creativity on this forum.
I hope you do proceed.
Two thoughts if you do:

Instead of summer tubes, 3 season tubes and winter tubes -- why not summer base level tubes then you add one thin tube of additional down to make it 3S and you add two thin tubes of additional down to make it winter.

My second thought is something I have been thinking of. Make two light down summer UQs. One for me and one is a loaner. If its cold then I remove the suspension hardware from UQ #2 and just insert it between UQ #1 and the hammock. Maybe four velcro points to keep it in place. Different than your idea, but still modular.

[mrmike65]

I like the idea fillable baffles! I wonder if you could use inflatable tubes instead. I mean isn't it the dead air space that provides the insulation? Or does down provide additional warmth beyond creating air space? I wonder what would weigh more - down or inflatable tubes?

[hang10]

i'm right there with ya, gargoyle. thin underquilts with easy baffling. the layers of the "tubes" could nestle in the crease between the baffles of the thin underquilt over or under it. you may even get more insulating dead air space between . you guys worry about weight but considering i was gonna go synthetic, i am seriously thinking of making this. maybe like 4 reinforced holes along the sides in the shell with loops on the underquilt inserts. figure my underquilt needed before i go and just run some zip ties through the holes and loops to keep it together. i like it!!

[FLRider]

I like the idea fillable baffles! I wonder if you could use inflatable tubes instead. I mean isn't it the dead air space that provides the insulation? Or does down provide additional warmth beyond creating air space? I wonder what would weigh more - down or inflatable tubes?

It's not just the airspace; it's the fact that the down (or whatever) prevents the air from moving around in the space. Convection currents are what causes a cold feeling, since the air moving around transfers heat (think of a gust of cold wind on a cool day).



To the OP: let me think on this for a day or two, and see what I can come up with. I'm a little fried right now, from a thirteen hour work day, so I don't think any of my first-approximation ideas are going to be all of that great right now. This is a good idea, though, I'm pretty sure...