I’ve been using various pads and mats with my hammock for a few years trying to find the best combination of warmth and pack size. You need insulation underneath you in a hammock as you loose a lot of heat on your back as the air passes underneath – it wont take long (even on a warm day) to feel this effect.
The NATO closed foam mat is by far the warmest and works well with a hammock because it conforms to your body shape, the downsize is it packs big. You pretty much have to have it on the outside of your pack. I don’t like this because I want everything inside my pack. In this way I can use packs that don’t look like I’m intending to sleep overnight – this helps with the stealth aspect of wild camping. If you have a small pack that looks like you are on a day hike then its less suspicious than wandering onto land with a fully packed Bergen and mats strapped to the outside. Also its just easier to carry and I like to set ceiling limits on what I carry as that’s kind of the point of this game.
Inflatable mats work well as they can it inside your pack but they are vulnerable to punctures and ‘system failure’. Also the problem with all mats is that they move during the night so you often wake up cold and have to try and readjust the mat while lying on it (not easy).
Another downside to mats is they only provide warmth underneath you and not on the side. My preference is to use a wool blanket in the hammock because its easier to get in and out of the hammock, also the wool blanket feels more hardy and I care less about it getting wet or dirty or damaged by fire. You can use (and I have used) a sleeping bag in a hammock but they aren’t easy to get in and out of the hammock with and the zips (especially on mummy bags) are difficult to fully zip up when inside – I’ve also used the famous Czech Army Bedroll (which I love) but you have to be a contortionist of houdini’s ability to get it into the mummy configuration once in the hammock , and woe betide you if you have a sudden need to go to the toilet! You can use a sleeping bag inside a bivvy bag so that you can stand up to get into it and then lie down but if you are using a Tarp then this can become tricky too (depending on the size of the tarp and how high it is above the hammock), I have a Yugoslavian army blanket (100%) wool which is good and thick but isn’t that wide. So its difficult to have a full wrap of single layer wool without feeling the cold on the sides somewhere. The blanket works well doubled up on top – this is almost too warm! but again you get the cold on the sides.
For all of these reasons I decided to try an underblanket and pulled the trigger on a DD underblanket. An underblanket is basically a sleeping bag that you attach to the underside of hammock so the air that gets trapped underneath is warmed by your body and kept there. Its also a wind barrier. The reason a normal sleeping bag on top of the hammock doesn’t work (as you will hear in every youtube post on the internet) is because sleeping bags rely on loft to trap your body heat – you produce the heat and the bag conserves it. When you are lying on the hammock the bottom of the sleeping bag is compressed, so loft is lost and heat too. In Scotland in August I was blessed with good weather, but even in a 3 season bag and bivvy bag with a Vango inflatable mat I still woke up cold because the mat had moved and the sleeping bag was compressed under me. By placing the underblanket beneath the hammock you dont lose loft so the problem is addressed. Also the underblanket fully surrounds the hammock so you get warmth on the bottom and the sides. Therefore using a wool blanket (or hammock quilt) is more viable. The other attraction is that they can be compressed so they pack small. because I want to have minimal kit id be essentially swapping my pad for the underquilt – which means its less likely I would ground dwell but I will always want to find someway of using the hammock in preference to ground dwelling (who wants to sleep on the floor in the rain? or on an incline? or on the pristine forest floor? or where dogs or other beasties are likely to come and check you out?). Besides I recently acquired a folding German mat from Combat Cellar in Northampton which folds tiny – its thin – but it would do in a pinch.
The underquilt comes with 4 bungy type cords that are tied off to the bag and have carabiners at the end. These ties offs are loose so you can retie them and adjust the rigging to your liking. DD say that every hammock after 2012 has loops that should accept these underquilt ties but I’m not sure about that. I bought my second DD camping hammock this year (because simplicity is divine) and it doesn’t have these loops. It doesn’t matter though because by adjusting the lengths of the tie-outs you you can use 4 at the head and 4 at the feet to clip onto the webbing at each end which bring the side of the quilt up flush with the hammock. You need to tighten the draw string on the sides, head end and feet end to make sure there is as little of an airgap as possible between you and the quilt. I like to sleep low in the hammock but you need enough clearance to keep the quilt off the ground. Im lucky enough to have two trees in the garden and I have slept outside for the last two nights as a test. I think its generally wise to test kit in the garden rather than Dartmoor 🙂 Its later September but its an indian summer and the coldest I saw it at was 10 degrees Celsius. There was wind chill though and last night it rained heavily around 5 am.
This is the basic setup (before I adjusted the rigging);
Here is some detail of the bungy rigging
Here is the hammock rigged with the Basha – you can see I’ve got it very low so trying to get in and out of this with a sleeping bag would be a nightmare! with the wool blanket though its a piece of cake.
On both nights i just wore a tshirt and trousers. the first night I slept with no Basha as no rain was forecast – and I like to look at the stars whenever I get the chance! I slept with the blanket in a single layer on top and tucked in on the sides, I wore no hat. I woke up all the time because I was cold! but not from the sides or bottom, I was cold on top and on my head because of wind chill. Also when using the quilt you don’t sleep diagonally as easily so I was in a straight line, and because you cant use your arms as pillows at night (because its cold) my neck was aching. But the quilt was great! The second night rain was forecast so I rigged the Basha and this time I trusted the quilt to do its job and doubled up the blanket on top (the quilt can keep my sides warm). I still wore no hat but there was less wind because of the cover from the Basha. I also brought my inflatable travel pillow out of the garage. Very comfortable and warm nights sleep and the only time I woke was during the rain and that was only to smile to myself at how awesome it is listening to the rain hitting your tarp 🙂
So yes – a success! its going in my pack for the next trip to test it in anger. I might look at a DD tarp though. The Basha is awesome but its small. The very top and bottom of the hammock gets wet and there isn’t much space so if you were stuck in a downpour for any duration you wouldn’t have much space to move around/cook/brew etc..