Macpac's Bush Cocoon (Pertex Shield Version)

Preface

From eVent to Pertex

A few years ago Macpac made some changes to their Bush Cocoon; they stopped using eVent (due to eVent's overly aggressive price increases) and replaced it with Pertex Shield Air.  On paper this drops the hydrostatic head from 20,000mm to 10,000mm (but 10,000mm, i.e. a 10 meter water column, is more than enough for a waterproof tent) and theoretically increases breathability. In practice we can't tell any difference between the two models. On a semi-superficial level, the colour is a major improvement.  We've gone from a bright "Nikau" green, to a far more subdued, olive-adjacent "Kombu" green.  

From eVent to Pertex.

Because there are no real design changes, this review uses images from the new Pertex and old eVent models. The test model of our Bush Cocoon is 15g heavier than the previous version, but that's well within manufacturing tolerance / variation. Macpac are good when it comes to accurate specs and we'd suggest going with their stated weights.

Before we begin the review, let's be clear who this product is aimed at, because it's not for everyone.
 

On The Move

If you spend a good deal of time sitting in and around your tent admiring the view or waiting for the sun to shine (i.e. camping), then this review may not be for you. If, however, you spend most of your time on the move and your tent is simply a place to crash before the next day's trek, then this review should be of some value ... we hope so.

Please see our companion post "Reasons To Go Modular" for the complete rationale behind us choosing a hooped bivvy + micro tarp setup. We'll touch on it briefly before getting to the main event: Macpac's Bush Cocoon.
 

A modular solution

At Scramble we like the modularity and flexibility of the 'bivvy + tarp' setup, in fact I'd go so far as to say, for long distance trekking, having the option to take a break pretty much anywhere in all conditions is now something I won't forego (for its morale boosting effect alone). But, we also like the all-round protection of a tent. Typically, at Scramble we want it all, so what's the solution?

Beefing up the bivvy; slimming down the tarp

We've settled on a compromise that works really well for long distance treks over multiple days and weeks. Rather than go with a good sized tarp and a lightweight bivvy bag, we've chosen to beef up the bivvy and slim down the tarp - this means a hooped bivvy and an ultralight (UL) "micro" tarp.

When combined with a micro tarp, a hooped bivvy gives you the best of both worlds: full protection when sleeping but also excellent coverage outside the bivvy; the tarp acting as an extended "tent porch" with better than average headroom (100cm) for cooking, getting changed, and packing up your stuff when it's bucketing down in the morning. The tarp allows for greater venting, reducing the condensation associated with single-skinned shelters, and provides protection for all the stuff you can't fit or don't want inside your hooped bivvy.

By modularising the tent, we get a robust all-weather protective shelter to get through the night and an indispensable quick shelter for short breaks in poor conditions during the day.

For details of the "porch / quick shelter" part of our modular tent recommendation see our review here. The rest of this review will be focused on our top rated, hooped bivvy / modular tent body, the excellent Macpac Bush Cocoon.

As always, we're looking at the Macpac Bush Cocoon from the point of view of long distance trekking over tough terrain.

Test subject: Height: 5ft 8"
Test item: Kombu Green OS (One Size)
Kit Tests: Winter, Summer, Spring
Disclaimer: None required (item not provided by manufacturer)

Datasheet

Manufacturer's Page

 

Scramble Review

Contents

• Introduction
• Design & Features
• Waterproofing, Breathability & Condensation
• Packed & Weighed
• Don't want to go lighter?
• Negatives?
• Conclusion & Rating

Introduction: Cocooned in a modular body

A hooped bivvy is somewhere between a normal bivvy, a bothy bag and a solo tunnel tent.

Like a bothy bag, a hooped bivvy provides completely sealed (yet vented) protection and is thus great in emergencies; if stuck on the top of a mountain, disoriented in stormy conditions, you can simply roll out the hooped bivvy, get in and wait out the storm. It's similar to a traditional bivvy bag in that it's still very much something you'll only really sleep in, but it's also a little like a low profile solo tunnel tent in that there's room for more than just you and a sleeping bag, the good designs are not claustrophobic or coffin-like, they'll likely include an insect mesh to protect against those "biting beasties" while offering additional venting options, and like a tent you can peg them down for stability in high winds and/or at high elevations.

Bivvies, hooped or not are single skinned shelters with a fully waterproof membrane (much like waterproof jackets) and like waterproofs, the top models use higher quality, more "breathable" fabrics (i.e. they not only keep water out, but also allow moisture to escape from within, at least in theory), the three main market leading fabrics being Goretex, eVent and Pertex. Macpac originally went with eVent (as did Rab with their Ridge Raider) but now use Pertex Shield Air for their Bush Cocoon (whereas Terra Nova opted for Goretex for their Jupiter bivvy, below right).

Design & Features

The first thing that sets the Bush Cocoon apart from the majority of the big name competition is the large side entrance which runs along two thirds of the Bush Cocoon's flank.

Why is a side entrance uncommon?

A Side Door !!!

How do you get out of a car? You open the door (which is on the side), swivel in the seat and feet first, step out. Pretty sensible. But if most hooped bivvy manufacturers had their way, you'd wind down the front windscreen (or windshield), notice it's raining, climb out head first over the bonnet (or hood) get your hands and knees wet and to get back in you'd reverse the process. But this time you'd slide in feet first, facing up (so you can see what you're doing), getting a wet arse in the process. Genius!

It's quite natural, when sleeping in a hooped bivvy to store stuff near and around your head (spare clothes and/or an insulated jacket may make up your pillow, you may have your maps and compass, a head torch and numerous other things you want inside and to hand - let's call this your "office"). But then, in the middle of a downpouring night, you need to make use of that vast toilet called "the wilderness outside my bivvy". Dragging yourself out of your sleeping bag you then have to clamber over the office (crushing your compass as you go, and) dragging the debris out with you. You want to put something on your feet, but your feet, unlike your head and hands are still inside the bivvy ... you see the problem.

Reversing the process, allows you to mix in some added mud and moisture as you and the flotsam and jetsam of what was your tidy office slide back into various parts of your now damp sleeping bag. You'll find the broken compass in the footbox, some time in the morning.  

Macpac, a New Zealand brand (known for their quality backpacks) clearly did some thinking outside the bivvy-box and sensibly, gave their Bush Cocoon a side entrance, and a large one at that. Not only does this allow you to exit feet first, putting on some boots as you do, but if you need a pee, you can just turn on your side and with a little care, urinate from the snug confines of your unzipped sleeping bag (at least if you're a guy).

If you're hunting or spotting and need to lay in wait with a rifle or binoculars poking out the front of your bivvy, then I completely understand a front opening, otherwise I absolutely do not.
 

Insect Mesh

Unlike traditional bivvy bags, hooped bivvies allow for a completely sealed off experience. In summer, the door can be left open and the Cocoon's insect mesh, which covers almost two thirds of the Cocoon's side, provides absolute protection from biting insects. A micro-tarp porch, allows one the luxury of keeping this open regardless of overhead conditions.

In mild but saturated winter conditions, where one experiences dew and not frost (more on this later), when temperatures are hovering just above freezing, it's possible to leave the door open and use the insect mesh as a massive vent - this reduces condensation significantly.

The outer door (as well as the mesh) can be rolled up and secured with the toggle fixture pictured below right.

The Bush Cocoon's insect mesh.

Space

The Cocoon has an interesting design (see illustration above); the hoop does not run approximately perpendicular to the side of the bivvy and this creates a useful storage space on the far side opposite the door of the Cocoon.

I've never felt claustrophic in the Bush Cocoon. In fact, on summer mornings it's very pleasant to lie on one's side, enjoy the view and the breeze through the large window, while cooking up a brew.

You and all your kit may be a tight fit

For shorter summer trips there's enough room inside the Bush Cocoon to store all ones gear, but only just. We tend to reserve the Bush Cocoon for more challenging conditions and combine it with our G-38 tarp which provides ample room to store ones gear outside the bivvy. Pictured below (at the end of the day, just prior to unpacking), is how we tend to use the Bush Cocoon.

A small tarp allows one to store kit outside the Bush Cocoon.

Inside the Bush Cocoon, there's enough room to study maps for the day ahead; there's a good deal of room around the head and shoulders and for those under 6 foot, likely some storage room at the footbox, but changing in and out of clothes is tricky, though not impossible. For three or four day summer trips, where one doesn't mind a little rain, the Bush Cocoon alone is an option. In a summer deluge, it would be possible (though frustrating) to get into waterproofs from inside the Cocoon and, in summer, kit dries out no problem. But for more extended trips and during the other three seasons, we recommend the micro-tarp setup pictured above and below (especially in winter, where sleeping bags and mats take up significantly more space).

Looking down on the Bush Cocoon with a decent sized porch provided by the G-38 tarp.

Ventilation

There is only one vent in the Bush Cocoon (some hooped bivvies have an additional vent at the foot end - we believe Macpac should implement one in their Cocoon - more on this later). In our view the head vent, though adequate, could be larger (meaning a larger hood too). This would likely add a little weight, but not much. The vent is well designed and well sheltered, but is more about preventing carbon monoxide poisoning than heavily reducing condensation (more on this later).

The Bush Cocoon's single vent - a little on the small side?

The Foot Section

From the hoop to the foot section many hooped bivvies resemble their non-hooped siblings in that they simply tail to a flat point at the feet. The Bush Cocoon has a built in sleeve intended for either a short pole or a stick (see below). I carry a lightweight 30cm pole section as very often I'm pitching above the tree-line. This incidental but nonetheless handy feature helps to increase the airflow around the bivvy and reduces the amount of condensation that ends up on your sleeping bag. In mild winter conditions I've found this has less effect due to the loft of the sleeping bag combined with saturated atmospheric conditions. But in the other seasons this certainly does improve things.

There are two guylines, one at the head and one at the foot, and this makes the Bush Cocoon a very robust and stable structure which excels in high winds.

Pictured above (left) you can make out the interesting (non-perpendicular) hoop angle of the Bush Cocoon.

Pole Sleeve

Some front-opening hooped bivvies have a flawed design, requiring the door to be open when threading the pole through the sleeve. The Bush Cocoon has no such issues, since it opens at the side, meaning the sleeve is not integrated with the door in any way. This means that the inside remains dry during pitching.

Not a great deal else to say here, except that the pole is a tight fit requiring a little force to get it into its grommets at either end, but this is as it should be and makes the structure rigid and stable.

The Bush Cocoon's pole sleeve

Accessories: Pegs & Poles

The 7 pegs that come with the Bush Cocoon are decent, U-pegs, each weighing 10g. I use a mix of Scramble's nail, Y-pegs and Tornados (depending on conditions). Since even though the Bush Cocoon is very low profile, I've been in edgy situations in high winds where feeling "buckled in" has reduced anxiety and allowed for a better nights sleep (at the cost of a few extra grams).

Reasonable tent pegs

Macpac have gone with the tried and tested, 9mm DAC NSL Featherlite Pole for their hoop. The same poles we recommend for the porch section. No issues here.

Excellent DAC NSL Poles

Pertex Shield Air: Waterproofing, Breathability & Condensation

It's impossible to talk about bivvies of any kind without mentioning the dreaded C word. But before we get onto condensation, a brief note on two associated factors: waterproofness and breathability.

Breathable & Waterproof?

Breathability is extremely hard to empirically qualify when out in the field. Certainly, eVent, Pertex and Goretex all have a reputation for being "breathable", but rather than us make unscientific guesses, here's a geek who ran some breathability tests on Goretex, eVent and Neoshell jackets - how much this translates to a bivvy is anyone's guess.

Since the shift from eVent to Pertex we've not noticed any changes in performance. So, although what follows relates to the eVent version, it applies equally to Macpac's latest incarnation.

In the first Winter Kit Test of 2017, I tested the Bush Cocoon in probably the most testing conditions possible. In search of ice and snow primarily to test an ice axe, I got unseasonably mild temperatures and unrelenting precipitation - useless for ice axes; ideal to test the Bush Cocoon. I described the conditions in another review like so:

Wales is known for its wet weather, [I went to] the wettest part of a wet country at one of the wettest times of year, but even the locals were surprised by the sheer relentlessness of rain, hail and snow (mostly rain). In those conditions, no amount of skill will keep you dry. Even when it was "dry" the air was dank and mizzle drifted in coating what was once dry, until eventually everything was wet, and stayed wet.

The Bush Cocoon's seven nights of rain, hail and some snow

Condensation

All single skinned shelters suffer from condensation, the more compact they are the worse the problem. The question is to what degree can this be mitigated?

All else being equal, as air temperature rises relative humidity (RH) drops - which is another way of saying the capacity to "hold" more moisture increases. So warm air can "hold" more moisture than cool air. When warmer, moist air cools near a cold surface, locally the RH rises until, saturated, the moisture is "released" in the form of water droplets or "dew" on the cool surface. This is called condensation.

The factors, that cause / exacerbate condensation in a single skinned tent or bivvy are:

• a high moisture level inside the bivvy (tick)
• a large temperature difference between the warm air inside and the cold air outside (tick - plus it was just above freezing so condensation was in the form of water droplets not ice)
• poor ventilation, so the moist air is not transported away (tick - I'd forgotten to pack some of my tarp accessories, which meant I couldn't ventilate the bivvy as effectively as I'd have liked)
• highly waterproof tent fabrics (tick)
• a high relative humidity (tick - everything was sodden, saturated and soaked for the full 7 nights)

So with all boxes ticked, under these circumstances condensation was quite an issue. But how much of a problem was it? Scramble's top-rated winter sleeping bag is an ideal bag in these conditions, being practically waterproof. A down bag would have been a different story. So although condensation is never pleasant, it wasn't actually that much of a hazard.

Macpac describe the waterproof / condensation conundrum well:

During periods of high humidity, such as during rain, it can be impossible to remove or reduce condensation. In these conditions, even a high degree of ventilation can actually increase the condensation rather than reduce it. In dry snow conditions, the humidity is usually very low, which can help to minimize condensation. The more effective barrier that the (waterproof bivvy) fabric provides to stop rain getting through, the worse the condensation problem will be. This puts our tent designers in a difficult position and they naturally tend to favour keeping the rain out.

So what can you do to minimise condensation?

• Minimise the amount of moisture within the bivvy
• Ensure that all available ventilation is used
• Pitch the bivvy to catch any available draft
• Leave damp items outside or in bags
• Dry out the bivvy whenever possible

Many of these recommendations point to the usefulness of combining the Bush Cocoon with a micro-tarp, especially for longer trips.

UPDATE: 29/03/18:  During the second winter test of 2017 and the following 2018 winter kit test, condensation was almost entirely negated by being able to vent the Bush Cocoon. The only area that suffered was at the footbox (see negatives) and we've amended our function score to reflect this.

Condensation issues solved by the use of a "micro tarp" (2018 Kit Test).

Packed & Weighed

When packed up Scramble's Bush Cocoon came in at 975g as shipped from Macpac. When packed, it's 37cm tall and 13cm in diameter. So reasonably compact.  The bags provided by Macpac are all good quality, so nothing to complain about here. All in all, it's a very high quality package.

The Bush Cocoon all packed up with somewhere to go

A complimentary product that's been quite useful, providing some added protection for when the Bush Cocoon is strapped to the outside of a pack, is Big Agnes' 7L Trash Can (pictured below on the left side of the Crux pack).

The Bush Cocoon on the Crux AX50 inside a Big Agnes "Trash Can" heavy duty stuff sack.

The "Trash Can" is a tough, durable yet relatively light stuff sack intended for collecting rubbish while "on the trail". Made from MIPAN Robic (a regenerated and tough nylon), the Trash Can weighs 60g and does a great job of protecting the Bush Cocoon from rock and spiky vegetation.

The Bush Cocoon fits the Big Agnes 7L Trash Can perfectly.

Don't Want To Go Lighter?

"But if you went for an ultralight tent you could have a tent and your beloved 'micro tarp' and it would still be lighter!"

This is true, it would also be nearly twice as expensive and in stormy mountain conditions, I wouldn't trust these ultralight tents as far as I could throw them, which at well under a kilo is a long way. For summer (and some 3 season use), they're fine, but we want a solution for all seasons. Furthermore, the amount of weight saving comes at a cost, and insanely lightweight fabrics and 1g tent pegs may provide UL bragging rights, but will not withstand the battering that our shelters go through.

When you're trekking over long distances, where you finally pitch can be less than ideal; these UL tents cry out for "magazine cover" perfect pitching locations. When you spend £500 on a tent, you tend to be far more timid and cautious about where you pitch, and you can end up protecting it as much, if not more than it protects you. So no, I'll stick with our tough, four season, modular setup even though, all-in (bivvy + micro tarp) it's twice the weight of some single UL solo tents. 
 

Any Negatives?

Condensation is a negative (not particular to the Bush Cocoon) but can largely be mitigated when combined with a micro-tarp, since the Cocoon has excellent venting at the head-end via the large side entrance. However, at the footbox we did get condensation which froze the top of the sleeping bag's footbox to the inner wall of the Cocoon. Not a huge deal but we feel that a vent at the footbox would be a welcome addition to help prevent this. We've docked half a point here.

Now that Macpac have remedied the colour issue, there's only one minor gripe. The tent pegs could have been better (they're adequate, but we feel they weren't up to the standard of the rest of the package).

Aside from that, the Bush Cocoon, as hooped bivvies go, is a real gem.

 

Conclusion & Rating

The ultimate body for a flexible, modular setup

In terms of design and choice of materials, the Bush Cocoon is almost faultless. The design is both innovative and highly practical - the side entrance being a major plus. The only point of potential debate is around the vent. Could it be larger? Possibly. Should there be another at the foot? We think so, and we've passed this suggestion on to Macpac - hopefully, one day, they'll listen. 

When combined with an UL "micro" tarp, the venting provided by the side opening solves most of the traditional condensation issues which plague single skinned tents and bivvies. With such a combination, one has a hybrid or partially double skinned tent, with excellent venting options, better headroom (under the tarp porch) than many solo tents - the tarp providing a superior cooking environment - as well as additional shelter for kit remaining outside the bivvy. The Bush Cocoon offers complete protection from the elements in winter and from insects and other annoyances in the summer. In the mountains, where conditions are hazardous and progress potentially life threatening (whiteouts etc), the Bush Cocoon can be deployed quickly and allow one to hunker down and wait out the danger. It's not an ultralight option, but it's tough and protective enough to use all year round, and for Scramble, Macpac's aptly named Bush Cocoon is the perfect "body" for a modular tent system.

 

Product Images

 

Rating (out of 10)

* The value score is derived from two factors:
1) Competitive Market Price (CMP). This represents our judgement of a competitive online price point if we were to stock the item. e.g. if we feel we would need to sell an item at 40% off (i.e. 60% of its full RRP) to be competitive, then our CMP score will be 6/10.
2) Customer Value Price (CVP). We then make an honest appraisal of the maximum price we would be willing to pay for the item (and we're mean). So if we'd pay 80% of its RRP our CVP score would be 8/10.
We then average the two scores to get our final value score, which in our example would be 7/10.

 

 

Last Updated: 12/06/24