UnderCover Tear Down Redux - Not too keen on the stock color scheme

[WetRivrRat]

So, I've read as much as I can find regarding the HH UnderCover and it seems that NO ONE has successfully reproduced this item...

Maybe I'm missing it, but just wondering if anyone has actually tried and succeeded?

The mods might say this should go under DIY, as it will be a new item, not a modification of the stock item, but semantics...

So, to sum it all up - I've read all of the deconstructions (and construction attempts) of HH hammocks, and I've read most all of the topics related to UnderCovers (general) and what I've come up with is the theory is that Hennessy & Crew came up with a pretty bomb-proof design that no one wants to muck with...

Well, I don't fall into that category of folks - so I'm on a mission to repro the HH stock UnderCover for the sole purpose of having one in a color scheme that I like...

Any input as to any lessons learned from your attempts (failures or successes) are MORE than welcomed.

Thus far I've borrowed a UnderCover from a friend and have 'mentally' torn it apart. Doesn't seem too difficult, but rather expensive for what it's made of - am I missing the point? The hardest part will be defining a pattern with which to work off of.
I can clearly tell that the final product dimensions are no where near the beginning dimensions, but after seeing the results of 2QZQ's UnderQuilt Protector and HC4U's & wilsonbmw's tear down {http://www.hammockforums.net/forum/showthread.php?t=670} I'm thinking I've got my ideas on how to build the UnderCover.

So far I'm about 60% done with a pattern/template and hope to have that finalized in the next week or so.

Again, any input would be awesome, I'm hoping to have it completed before Fall Sprawl '12 - not so I can show it off, but so I can actually test it, since 'cold' is so overrated in FL.

And yes, once I get it completed I'll update with pics - but only after I've tested it and know it works or doesn't

[captaincoupal]

I found a basic shape to start with, that I used to modify the PLUQ - here's the thread for the illustration http://www.hammockforums.net/forum/s...ad.php?t=42216

I added a 3" border around the whole thing with pass-through holes at the 2 corners. This got me the HHSS, but shorter. I'm thinking that adding additional material at top and bottom would complete the setup, but I chose to do shock cord instead.

[FLRider]

I think DaleW fiddled around with this about a year back with a poncho replacing the undercover, so that it could be a multi-use item.

Maybe a little less than a year. You might want to shoot him a PM and see what he came up with.

[WetRivrRat]

{...} once I get it completed I'll update with pics {...}

Well, here are some pics of the template that I've made - I still have to cut and sew the darts and the entry, however I haven't exactly determined how I'm going to build the entry -
Do I mirror the HHSS entry, or do I design my own???

Anywho - here's the pics (sorry if they are grainy, its because of the window in the background)

[psyculman]

Thanks for the pictures and information/pattern. The SS is a difficult item, it has so many angles I never could get an accurate idea of the lines. I tried just a gathered end type of cover, but, the asymetrical configuration makes a straight line gathered end under cover not work at all.

This is my next project. Only I will be adding a channel directly under the "butt" area. A stretch cord will pass through the channel, and extend up over the structural ridge with a chord lock, to keep the bottom up against the hammock, thus no annoying air gap. (cbs) I have added a channel to the "upside" of my down UQ across the "butt" zone with an elastic cord up and over the ridge line, and it works very well.

[WetRivrRat]

{...}keep the bottom up against the hammock, thus no annoying air gap. (cbs) {...}

hmm... Interesting...

I'm actually shooting for the complete opposite of this theory - I've fiddled with the HHSS enough now to notice that it's built in such a manor that it actually becomes load bearing under my weight (210#) in my ExUL. So, I've actually had to take the template shown above apart and add several inches of fabric to address this issue.
It would seem to me that the ideal in this scenario would to be to actually have an air void, as the presence of the non-breathable fabric would create a vapor barrier. Also, giving it an air void would allow the condensation to occur on the inner layer of the outer barrier. Furthermore, it seems to me that having the air void would help to insulate any sort of UQ that is in place.

Maybe this is ignorance, and it should actually be tightly fitted, but it just seems too 'right' to have a void. Mainly if for just the simple factor that nearly all insulation is rated based on it's ability to maintain resistance to heat transfer. While in general, 'air' isn't the greatest insulator, at least when trapped between two layers of a container it would absorb certain amounts of heat radiated off of a person and with one layer being non-porous it would seem to make sense that this would resist the loss of the radiant heat, thus minimizing the convective heat loss at a point of lapse that would equal the point of increase of ambient temp in the air void due to both convective/radiant heat loss. Thus, an inherit R-Value due to the trapped air void.

Again, this is totally just my understanding, and I'd like those more intelligent in these matters to chime in and help us all out.

edit...
I guess where I'm going with that is this: For some reason or another I recollect that 'air' has an R-Value of '5' per inch of thickness. That being the case, the HHSS UC with my weight produces 0 inches of thickness of trapped air, therefore providing an R-Value of '0'. Furthermore, being that it is acting as a load bearing support, I KNOW that it is against my body, so any breeze that hits it is going to effect convective cooling against the area of the UC exposed to the breeze, thereby effecting conductive cooling of my body against the area of the hammock/UC that it is exposed to. Even worse than that, is that any radiant heat is probably lost as well due to the lack of void between the 'condensation' layer.
If I alter the DIY UC to have at least one inch of void between the hammock and the wind then I cut the convective-to-conductive cooling down to a minimum, and I implement a heat transfer resistance value of 5, which only serves to enhance any R-Value provided by whatever sort of Under Quilt I choose to implement depending on the season. Plus, I also implement a void that separates my body from the condensation layer - which is always a good thing if you already sweat like a beast...

but this just may be the beer talking...

[BillyBob58]

Good looking work there, WRR!

hmm... Interesting...

I'm actually shooting for the complete opposite of this theory - I've fiddled with the HHSS enough now to notice that it's built in such a manor that it actually becomes load bearing under my weight (210#) in my ExUL. So, I've actually had to take the template shown above apart and add several inches of fabric to address this issue.
It would seem to me that the ideal in this scenario would to be to actually have an air void, as the presence of the non-breathable fabric would create a vapor barrier. Also, giving it an air void would allow the condensation to occur on the inner layer of the outer barrier. Furthermore, it seems to me that having the air void would help to insulate any sort of UQ that is in place.

Maybe this is ignorance, and it should actually be tightly fitted, but it just seems too 'right' to have a void. Mainly if for just the simple factor that nearly all insulation is rated based on it's ability to maintain resistance to heat transfer. While in general, 'air' isn't the greatest insulator, at least when trapped between two layers of a container it would absorb certain amounts of heat radiated off of a person and with one layer being non-porous it would seem to make sense that this would resist the loss of the radiant heat, thus minimizing the convective heat loss at a point of lapse that would equal the point of increase of ambient temp in the air void due to both convective/radiant heat loss. Thus, an inherit R-Value due to the trapped air void.

Again, this is totally just my understanding, and I'd like those more intelligent in these matters to chime in and help us all out.

edit...
I guess where I'm going with that is this: For some reason or another I recollect that 'air' has an R-Value of '5' per inch of thickness. That being the case, the HHSS UC with my weight produces 0 inches of thickness of trapped air, therefore providing an R-Value of '0'. Furthermore, being that it is acting as a load bearing support, I KNOW that it is against my body, so any breeze that hits it is going to effect convective cooling against the area of the UC exposed to the breeze, thereby effecting conductive cooling of my body against the area of the hammock/UC that it is exposed to. Even worse than that, is that any radiant heat is probably lost as well due to the lack of void between the 'condensation' layer.
If I alter the DIY UC to have at least one inch of void between the hammock and the wind then I cut the convective-to-conductive cooling down to a minimum, and I implement a heat transfer resistance value of 5, which only serves to enhance any R-Value provided by whatever sort of Under Quilt I choose to implement depending on the season. Plus, I also implement a void that separates my body from the condensation layer - which is always a good thing if you already sweat like a beast...

but this just may be the beer talking...

Keep in mind that even with a gap there, keeping the sil-nylon from contacting your hammock and keeping you from feeling all of the wind, it is only sil-nylon. If not backed up with some insulation, that wind can still push that sil-nylon past the gap and against your hammock, I suspect. Oh, and totally disrupting that "dead air space" built up in your UC. At least it seems to me it could. But I have never really tested it, so you test it for us!

The "load bearing" aspect helps support the HH pad, and any added insulation, holding it just barely snug against my back and butt and even legs for the most part. ( as with most UQs, there is a falling away to the left side of my legs when I lay on the diagonal. I have minimized this by using a shock cord mod to help lift in that area)



The "load bearing" or elastic tension serves to hold the HHSS pad and space blanket on top of it snug against your back, Just snug enough for no cold gaps. But not snug enough to compress the OCF pad significantly. It also serves to hold other insulation placed in the UC up against the pad, although it is enough pressure in some spots to significantly compress 800+ down. Any gaps = cold. Unless you manage to fill the gaps with puffy loft. In which case there is once again no gap.

If you have no tension or "load bearing, how are you going to keep the pad/SB ( if you are using them? ) snug against your back? The pad has a harness, but I don't think that is enough to do the job. ( not trying to discourage your plan, just thinking out loud about possible challenges )

If you have a gap allowing any condensation to not come in contact with the insulation or your back, then what is going to support the insulation in order to keep it snug against your back? Well, maybe a separate UQ suspension? I don't get any condensation using the system as designed though some folks do. The UC tension holds the pad/space blanket against my back, in theory keeping the SB warm and in theory preventing condensation against it's warm surface. ( condensation tending to occur against cold surfaces, not warm) And in theory serving as a vapor barrier to keep insensible perspiration ( vapor ) from traveling through the insulation and condensing against the cold UC. This theory has always worked perfectly for me, but not for every one.

I will be interested to see what you figure out works!

[WetRivrRat]

You've got some good points, definitely some things to consider - I may be an odd one though because I sweat SO much when I sleep - we HAD one of those liquid proof bed covers and I've literally woken up in pools of sweat on multiple occasions. I know it's gross, but that's just me...

BTW when I say load bearing I literally mean load.... bearing.... as in there is absolutely no room left, the seams are under duress...

I'll be making my own under quilt as well, and I plan on making it so that it pulls up and around my body pretty close. I do sleep cooler outside than I do indoors but I haven't thought through the actual design yet.

[BillyBob58]

You've got some good points, definitely some things to consider - I may be an odd one though because I sweat SO much when I sleep - we HAD one of those liquid proof bed covers and I've literally woken up in pools of sweat on multiple occasions. I know it's gross, but that's just me...

Well, that sounds hard to deal with!

BTW when I say load bearing I literally mean load.... bearing.... as in there is absolutely no room left, the seams are under duress...

WOW! Do you mean with an actual factory HH SS UC? I have never had that kind of tension with any of my UCs. In fact, I can normally reach out (on a no net model UL Explorer ) and easily pull the UC down quite a few inches lower, even from the point of maximum tension/compression.

[WetRivrRat]

{...}WOW! Do you mean with an actual factory HH SS UC? {...}

yah, in fact the friend from whom I'm borrowing it from was looking at it from underneath as I was in it (we were trying to evaluate the air void) pointed out how tight it was -
It wasnt until I made the necessary changes to the template to create the 1" void that we noticed how 'bad' it was. I ultimately ended up adding about 5-7 inches of extra fabric to get a consistent 1" void. Once we saw how much fabric I had to add we started thinking about how much 'lift' the UC was adding, and we are going to to a unweighted vs weighted hang to see what the differences are between where the hammock hangs (height from the ground) with and without the UC on.

Now two things,
One- the 5-7 inches of extra fabric is not the finished product, I'm still trying to find the best lay for the darts and where I can remove excess material based on an average sleep positions, etc - so that number could fluctuate
Two- It is my understanding that my suspension lines should not have stretch memory (default ExUL lines) but they do, I have a permanent mount system in my house and I leave my lashings in and the hammock hung when I'm home, unless we need to get to something on the other side of the room - when I take it down I have to pull pretty hard or undo one of the lashings to hang it back because it recoils. I generally see about 3" min stretch - but have seen up to 6" depending on how much of the full lines I use (~ 1" per 1' used)

So it may be that my weight or my hammock causes the scenaro to occur, alls I know is that I don't get any freedom of movement with the stock HHSS UC - which is not a complaint - just an observation

Oh, and the duress... Probably less a destructive duress and more of a 'super stretchy material' streching around the threads - and it was only in my bum and upper shoulder area on the mid-seam, where the highest areas of weight loading was occurring.