The PeaPod System for Hammock Warmth

 
by Ed Speer Dec 2003

The Speer PeaPod:  An insulated blanket specifically designed to completely enclose an occupied hammock in such a manner that it provides sufficient warmth for sleeping comfort

 

"What makes the PeaPod the best warmth-to-weight-and-bulk ratio yet developed for staying warm in a hammock?"  Every time I'm asked that question, my mind wonders back to the countless pieces of gear and endless combinations I've tried in the battle to stay warm in my hammock.  And what a battle it has been!

 

The most obvious way to stay warm incorporates the sleeping pads already in widespread use for ground campers.  See the November 2003 issue of Hammock Camping News for more information on using sleeping pads in hammocks: http://www.hammockcamping.com/Newsletters/Nov2003.htm However, the thickness required for cold temperatures results in unacceptable expense, bulk, and/or weight for most backpackers.  While the sleeping pad solution is workable for many folks in warm to cool temperatures, I continued to search for a solution for subfreezing temps.

 

While many ideas instantly presented themselves over the years, most were abandoned on the battlefield when less-than-ideal conditions proved their shortcomings.  As the challenge got tougher, I resorted to trying less-conventional methods--unfortunately, the results were not encouraging.  After trying and rejecting a lot of commercially available gear, I was forced to make my own.  But still the answer was elusive, until one fateful day when a fellow tree hanger bemoaned the loss of insulation in his sleeping bag beneath him in the hammock and wondered aloud about the possibility of using an extra large sleeping bag around the hammock!  I instantly knew it would work and set about making my first prototype!

 

The early tests were positive and soon the PeaPod was born.  It is extra long to extend the full length of the hammock (i.e. 9 feet for an 8-foot hammock).  It has extra girth to accommodate the side sleeper with knees drawn up.  It was quickly learned than smaller dimensions result in constrictions that reduce the loft of the insulation--thus most commercially available sleeping bags are not up to the job.

 

The PeaPod has drawstring end closures and a full-length central Velcro closure.  This allows it to be positioned around a hammock already strung between trees.  The PeaPod can also be removed without taking the hammock down.  These features are useful when the PeaPod is to be used as a warm robe in camp (more about this later).  The PeaPod can also be used in the more-normal way as a regular sleeping bag or it can be opened flat and used as a large blanket.  Two PeaPods easily Velcro together to make an extra large sleeping bag for ground sleeping couples!

 

Velcro was chosen for the full-length central closure instead of zippers for reliability, weight savings, and ease of opening to exit the hammock.  Searching for zipper sliders in the darkness proved frustrating--Velcro can be opened at any point.  Securing the Velcro closed is simply a matter of grabbing each side, pulling them straight and touching the Velcro strips together.

 

With its' full-length Velcro closure, the PeaPod can be entirely enclosed around an occupied hammock or left open as much as needed.  For warm temperatures, it can be left open on top, in which case it serves as a bottom blanket providing warmth on the bottom as well as the sides.  For colder temperatures, it can be closed along the top, leaving an appropriate breather hole over the face.  In really cold conditions, it can be completely closed above the face without fear of suffocation (note this does add considerable expelled-breath moisture to the insulation above one's face--however, there are times when the added warmth may be worth the tradeoff)! 

 

Note that the PeaPod is designed to work with a top-entry hammock such as the Speer Hammock (with ridgeline and bug net removed).  Unfortunately it does not fit around camping hammocks that have a permanent ridgeline and bug net.

 

The PeaPod is attached to the hammock by tying the end drawstrings around the hammock end knots in such a way that the ends of the PeaPod lie just inside the hammock end knots.  The PeaPod is then wrapped around the hammock as much as needed.  As mentioned below, the drawstrings can be loosened as needed to avoid undue stress on the PeaPod that reduces the loft of the insulation.

 

Lightweight nylon fabric with a Durable Water Resistant (DWR) finish was chosen for its' durability, wind blockage, and quick drying in the field.  Breathable fabric was chosen over vapor barrier to allow evaporation of body moisture, which otherwise is a serious problem below the body, especially in cold weather.  Waterproof-breathable fabrics proved troublesome as they retained too much body moisture.  Vapor barriers can be employed inside the PeaPod for extreme cold weather if desired-- for more information on vapor barrier use, see Chapter 6, How To Stay Warm in the Hammock Camping book at http://www.hammockcamping.com/ or the January 2003 issue of Hammock Camping News at http://www.hammockcamping.com/Newsletters/Jan2003.htm.

 

But the real versatility of the PeaPod comes from the fact that it can easily be enhanced with extra insulation as the temperature drops!  While alone it can provide all the needed protection for warm to cool temperatures (i.e. 70-45oF), the PeaPod readily becomes the key part of a component system for colder temperatures.  Adding a top blanket inside the PeaPod-wrapped hammock is useful for most folks.  This can vary from a light sheet or fleece blanket to a summer-weight sleeping bag as the temps drop.  The top blanket fills the space above one's body where the sides of the hammock hold up the PeaPod. 

 

Note that blankets or quilts over the top of one's body function better in a hammock than struggling to get into or out of a sleeping bag.   Top blankets or quilts should have a foot pocket to accept one's feet--the foot pocket and the sides of the hammock hold them in place.  When using a sleeping bag, turn it over so it works similar to a top blanket.

 

As colder temperatures call for thicker top blankets, the old top blanket can now be used as a bottom blanket or liner inside the PeaPod!  In this manner, warmth at any temperature is possible!  And this allows a single PeaPod to function over a very wide temperature range.  At colder temperatures, you must carry more insulation anyway, even if you were sleeping on the ground.  In a hammock with a PeaPod, you can get maximum warmth with the least bulk and weight by combining your gear as components added incrementally to the PeaPod.  In other words, the PeaPod with Bottom Blanket Liner and summer-weight sleeping bag as Top Blanket should be the weight and warmth equivalent of a winter sleeping bag and sleeping pad used on the ground!

 

As ever-thicker bottom blankets are added, the PeaPod should be loosened to accommodate the new thickness--retying the ends with more slack is called for.

 

The current Speer PeaPod and Top Blanket are both filled with 0.8" thick LiteLoft synthetic insulation.  However, the Top Blanket is large enough to fold double lengthwise when used as a Bottom Blanket inside the PeaPod--that gives 2.4" of insulation beneath the hammock sleeper!

 

Other items can also be used for additional bottom insulation.  Sleeping pads placed between the hammock and the PeaPod add great warmth without the usual loss of comfort or hassles with slipping common to pads used inside the hammock.  Clothes in your backpack but not worn to bed can provide excellent insulation when placed inside the PeaPod as liners--use your rain suit, wind suit, fleece sweater, insulated jacket, shirt, pants, long johns, etc,  Even folded ground sheets or tarps can be used in this manner for extra bottom insulation.  Frameless backpacks, pack rain covers, and stuff sacks can also be used effectively in this manner--most anything already in the backpack can be used!  The amount of additional bottom warmth will surprise you!

 

But we're still not finished--at certain times of the year, vast amounts of natures own insulation is available.  Dry leaves or dry grass make unbeatable insulation!  With no extra carried weight, all the insulation needed is often easily collected right off the ground.  Packing dry leaves or grass into the PeaPod can give 3-5" of compressed insulation--enough for 0oF!  All without carrying an ounce of extra weight!  I've used this technique numerous times and highly recommend it--just be sure and return the dry leaves or grass to the spot where they were collected.

 

The following table suggests some specific temperature ranges for your consideration.  Note that the Speer Top Blanket, at 0.8" thick, can be exchanged for the sleep pads when used as a Bottom Blanket inside the PeaPod!  Note also that cold wind will greatly alter the temperature ranges given in the table--testing your own gear in all conditions at home before heading for the backcountry is highly recommended.

 

   How To Stay Warm In A Hammock

Using the Speer 1.6" Loft Synthetic Pea Pod

 

                                                        Temperature in Degrees F (no wind)

 

+75

75-65

65-55

55-45

45-35

35-25

25-15

15-5

Fabric Treatment

 

 

 

x

x

x

x

x

Pea Pod

 

 

x

x

x

x

x

x

Sleep Pads:

 

 

 

 

 

 

 

 

   1/4X22X47

 

 

 

 

x

 

x

x

   1/2X24X54

 

 

 

 

 

x

x

x

Mylar Sheet

 

 

 

 

 

x

x

x

Top Blanket:

 

 

 

 

 

 

 

 

   Thin Sheet

X

 

 

 

 

 

 

 

   Speer Top Blanket

 

X

X

X

 

 

 

 

   30o F Sleeping Bag

 

 

 

 

X

X

 

 

   20o F Sleeping Bag

 

 

 

 

 

 

X

X

Clothes:

 

 

 

 

 

 

 

 

   Thermal Long johns

 

 

 

 

 

 

 

 

      Lt wt

 

 

 

 

X

 

X

X

      Med wt

 

 

 

 

 

X

X

X

   T-Shirt

 

 

 

 

 

 

 

 

      Short Sleeve

X

 

 

 

 

 

 

 

      Long Sleeve

 

X

X

X

 

 

 

 

   Socks

 

 

 

 

 

 

 

 

      Lt wt

 

X

X

X

 

 

X

X

      Heavy wt

 

 

 

 

X

X

X

X

   Balaclava

 

 

 

 

 

 

 

 

      Lt wt

 

 

 

 

X