UKH

The Marmot Nabu is a great winter mountain jacket, but the air-permeable nature of Polartec NeoShell makes us think again about our expectations of shells, both hard and soft.

In this review Toby Archer explains all...

Read more at http://www.ukclimbing.com/gear/review.php?id=5883

In reply to UKC Gear: Hi Toby. Thanks for the review. You didn't mention how ridiculously large the sizing is on this jacket. I'm 6ft and 70kg so a standard medium. I tried the Marmot medium on in a shop and wouldn't ice climb with that much bagging around the waistband, while the small is too, well, small (in the arms etc). How did you find the fit?

In reply to UKC Gear: Interesting review. On the windproof point, is the air movement through the fabric something that is only noticeable in high(ish) winds on the bare skin of your arms? Would wearing a long-sleeve base layer be sufficient to avoid this?

In reply to BnB: It's odd because it fits me fine in medium. I'm about 177 cms (5'10"-ish) and I think about 75 kgs (32-34 waist). It might not be particularly slim fitting but I can't say I got annoyed by any bagginess when using it with a harness for example. Perhaps these things are actually quite personal in what we mind/don't mind.

In reply to nikk44:

Nope, you can notice it when you have a long-sleeve base layer on, particularly when its sweaty.

In reply to UKC Gear: another review of the nabu, with some pictures of the soft inside and the 'fit'.

http://gearthirty.blogspot.co.uk/2013/02/marmot-nabu-neoshell-softshell-hig...

In reply to nikk44:

I used my Neoshell jacket last Winter. Conditions were generally very good, with light winds being the norm.

There's no doubt that despite the good weather I felt quite a bit of air movement through it that you wouldn't get with a Goretex shell. I wouldn't call that a problem as such. The breathability of the material is excellent- which contrasts with my experience of Gore shells.

As Toby says in his Marmot jacket review, at least you can add a windproof layer when required (belay jacket, windshirt etc). You can't make a Gore type shell more wind permeable except by using pit zips etc.

In reply to UKC Gear: I use a mammut gipfelrat and find that if I use it with a marmot dry clime under the shell I have no issues with condensation or unwanted airflow. Nice review.

In reply to David Bennett:

That makes lots of sense David - the driclime obviously is a windproof layer. Will experiment more myself with this as the winter goes on.

In reply to UKC Gear: "My feeling is once you have a mid-layer or -layers on the sensation will become unnoticeable, particular so as people increasingly use for a mid-layer synthetic puffy insulation that has windproof outer of Pertex or similar."

By adding a windproof layer beneath the garment you are going to effect the breathability of your layering system and defeating the object of neoshell. Also, adding an insulated shell layer underneath (or any extra layer), to combat this negative side affect of air permeable membranes, will cause you to run hotter.

As I mentioned in the other thread, it's more than just feeling the wind coming through Neoshell that's the problem. It's the wind coming through a damp layer which acts like an air-conditioning unit, and is freezing cold (even when windchill alone is above freezing). The neoshell layer will always be damp as there's a constant exchange of moisture going on.

Mammut also states: "It combines the weather protection credentials of a hardshell with the outstanding moisture regulating performance of a softshell"

I always thought weather protection for a hardshell was wind and rain? Having used windproof layers that aren't waterproof over soaked base and mid layers I know that windproofing is vitally important to survival in the mountains.

I think that this marketing as "hardshell performance with softshell performance" needs to stop, and just call them waterproof softshells.

In reply to Martin1978:


Exactly, but that is an increasingly unfashionable point of view. Lots of people do it, so you must be wrong.


But I've had softshells that were certainly not waterproof but were *effectively* windproof, in that I could not feel a stiff cold breeze through them despite only wearing a thin or medium baselayer underneath.

In reply to Martin1978:


Of course you are, although I've always found things like Pertex and Marmot driclime breath plenty for me and I'm a hot, sweaty type on uphills


I guess only if your windproof layer isn't breathable at all.


Of course - adding any layers under a shell makes me sweatier if I'm going up hill.


Physics suggests this is true although that doesn't take into account the warmth gains that increased breathability should also offer. If you are wearing a less breathable jacket and sweat builds up wetting your under layers, then you will be losing heat by conduction too. Does one offset the other? Is one process more important than the other? Under what atmospheric conditions? Mr Fuller is probably the person best placed to discuss this; I suspect insulation/heat loss mechanisms on an exercising human will be very very complex with atmospheric conditions and individual physiology making things alter wildly.


But breathability is also important for hardshells, because if they lack this and you wet out your own base and midlayers, that also means you will lose heat rapidly. If gortex is wind protection 2, rain protection 3 and breathability 1, and neoshell is wp 1, rp 2 but breathability 3 (and of course those are completely made up values to illustrate a point) then you could say they are different approaches to offering the same level of protection?

From my experience of two different NeoShell jackets now I don't want to over-stress the air perm issue. Yes; I think it is MORE noticeable than Polartec claim, particularly under the conditions I point out. But it is not as if the material has no windproofing qualities at all. It is actually rather windproof; just not as much as Goretex*.

*Matt Fuller, IIRC, also pointed out that windproofness is a factor of they physical rigidity of the material as well. A soft light thin material (gore paclite for example) will deflect in wind and 'pump' air around inside your clothing possible causing convective heat loss. Probably lots of us have noticed that a heavyish 3 ply goretex mountain jacket with tough facing material is 'warmer' than a very light flexi paclite jacket for example.

In reply to Damo:


Absolutely, my old Buffalo stuff always felt like that.

In reply to TobyA:
>

Yes, good point. A related issue is that thinner, flimsier materials get pressed against you by the cold wind you so you actually feel the cold more, esp if your baselayer is damp, whereas a stiffer fabric, or mid layer, will offer more of a barrier and so prevent this. Same cold, same wind, same conditions, (maybe) same number of layers, but a different experience due to the rigidity/thickness of the outer layer.

In Antarctica there have been several cases of frostbite in the inner thighs that I know of, that were caused by the effect of the cold wind pressing thin pants fabric hard against the inner thigh, while the people were pulling sleds into a headwind. Other people out in the same conditions, same place, same time, but with thicker pants had no problems at all.