Cairngorms trip Bivvy options

[chambo82]

Morning all , I have a week long packing trip in middle of May and trying to decide on which bivvy bag or tent to take ? The aim will be to make it to Bothy stops all being well but incase this doesn't happen we need the option of staying out, 1 of the others has an Alpkit bag and had to go for the xl version so bit worried about buying a bag online and sizing to be dodgy , I'm just over 6ft tall and around 90-95kg and have looked at bags with a hoop around the head section and also small tents , weight not massive issue as I'm no lightweight myself !!! lol although lighter the better if possible , any guidance / personal experiences appreciated all
Cheers

[whitestone]

There's a few threads on bivy/bivvy/bivi bags (spelling is variously random!) Basically standard bivy bags are too small in girth if you want sleeping mat, sleeping bag and yourself inside especially if you've one of the deep plush mats like the NeoAir or Exped mats. Some manufacturers quote girth, some width but since the "width" is measured when the bag is empty and laid out flat then girth is simply twice the width.

Standard bags are 75 - 80cm in width, large bags around 90cm in width.

The other consideration about bivy bags is rain protection at the head: you can't fully seal them due to CO2 buildup in the bag. For this reason many will use the bivy bag in combination with a tarp. However you are now getting towards the weight of quite a few lightweight tents so the choice isn't as straightforward as you might think. In the end it's personal preference. Mine is for a bivy bag with tarp as it's more flexible in where you can pitch since a tent is only ideal if you can find a spot that is big enough and smooth enough to pitch it according to the manufacturers instructions.

[Mariner]

Another consideration is volume.
A Skyscape X cuben fibre tent passed through my hands briefly recently.
It was 1kg lighter than my regular tent yet strangely the same volume and cost four times as much.
My bicycle 7 tarp is tiny in comparison.
Weight vs volume hmm tricky.

[Justchris]

Rab storm. Bug net. Open or closed hood. Not the most breathable but fine as a just in case bag.

[chambo82]

Hmm decisions decisions !!!

[Bearbonesnorm]

Hmm decisions decisions !!!

Indeed.

The Hunka XL is plenty big enough for a winter bag and mat on the inside and breathes very well - helped by breathable material on the top and bottom, although having a mat on the inside will negate this slightly. As a 'just in case bag' it's brilliant but as Bob says, there's the issue of what to do with your head should it rain. Pulling your jacket over your face works reasonably well as does closing the hood up fully and rolling onto your side but that's not easy with an air mat inside.

I don't really get hooped bags, although I'd quite like to try an Outdoor Research Helium as the additional headroom seems to come with very little weight penalty.

If midges, slugs and other delicacies are a concern, then as Chris says, the Rab storm's a reasonable bet or the Rab Ascent if you want superior breathing and don't mind additional expense.

Something like a SMD Lunar Solo, would cover all bases but seems an expensive 'just in case' option ... as does everything else I've mentioned bar the Hunka.