Hammocking, and underinsulation requirements

[andrewa]

As the MYOG viewers will know, I've recently made my "ultimate" quilt and underquilt for my Hennessy Hammock, having carefully searched the hammockforums site , but wonder whether I've overdone it.

Today, whilst sorting out how to hang my UQ below my hammock, I realised that what I've made may well be too warm for what I need in NZ in January.

Temps there are only going to drop to about 10C at night. I'm wondering whether a bit of 2mm closed cell foam may be enough? I'm happy to tuck my UQ away for colder temps.

Andrew A

[Macca81]

Drop it down a touch at the ends so air can flow in. I can garuntee this will cool you down

[HitchHiking]

Ive gone lower then 10 Degress with a car windscreen reflector. I think it was about 7ish. I also had a good top quilt. Depending on how you feel the cold a blue mat might do it. Can also take it onto the ground if you had to.

[Tiffany]

I tried out my henessy with just a self inflating foam mat and a sheet last week. I was out at lamington in QLD and it got very cold. I think it was about 15 degrees. I am normally a snow lover and run around in a t-shirt during winter, so it was a bit of a surprise.
The mat underneath kept me fairly warm, but I was searching for more things to put over me so I could stay warm. Warmer clothes or a top blanket is definately on my list for next time.
I hadn't considered a car windscreen reflector before. Good idea HitchHiking.

[Nuts]

Im no hammock hanger but ive been wondering why under insulation is needed, saw a discussion somewhere including a calculation that a reflective layer 1" under a hammock was equivelent to r8 sleeping mat (as there is no convective losses)?? They were talking about using a heatsheet but obviously it needs some way to maintain the constant 'gap'.

[photohiker]

Im no hammock hanger but ive been wondering why under insulation is needed

Conductive losses. Where your body contacts the hammock, your exposed area is in near contact with the ambient outside air. Windchill multiplies the effects.

A heatsheet sounds like a great idea, but there are implementation issues: Maintaining the gap and excluding air movement. Not so easy when the shape of the hammock changes everytime you move...

[ULWalkingPhil]

Without a under quilt or pad, laying on a hammock is very cold.

A couple of weeks ago on my last overnight hike, overnight temp got down to 15 degrees, with my under quilt and top quilt, I was very warm. Actually a bit to warm, had to take the top quilt off. My top quilt is a -7 down bag, and it only weighs 600 grams.