Today in this article, we’ll be discussing everything about bivy sacks considering the following outline:
Everything you need to know about a Bivy Sack
What is a Bivy Sack?
Bivy; also known as bivouac sack, were invented to serve climbers who wanted and needed ultralight emergency protection for their sleep systems when they were out for an ascent. Originally, bivy sacks were nothing more than a nylon shell that was essentially waterproof but it really offered nothing more than that. It was quick protection from a quick rain or snow event that allowed you to essentially make camp anywhere in places that were impossible to do so with a tent.
Since their creation, bivy has evolved; technology has changed and people are using them for all sorts of reasons including military forces all around the world. Think of a bivy as a single wall tent because that is what they are, there are many different types and they have different types of opening different materials.
Types of Bivy
On the basis of protection, bivy is classified into three types.
- Limited protection Bivy
- Partial protection Bivy
- Full Protection Bivy
Limited Protection Bivy
Limited Protection Bivy is made of a simple nylon shell and this is really to protect you from splashing. You have this underneath the tarp; maybe it’s raining; the wind’s blowing a little bit and water splashing up on, this protects your sleep system.
Partial Protection Bivy
Partial protection bivy is more robust than a Limited Protection Bivy and classified as a military level sleep system. It is made from gore-tex; it’s quite a bit heavier and this will offer you a lot more protection than a nylon bivvy.
Full Protection Bivy
A full protection bivy offers 100% protection as it’s waterproof and also it can be zipped up 100% to prevent bugs from getting in and whatnot.
Related: Best Bivy Sacks in 2021
Majorly, bivy’s are made up of two types of fabrics; nylon, Gore-tex, and you have other materials out there. Gore-tex tends to be the most expensive, heaviest and also the most breathable.
An opening of a bivy is different on every single model; some are easy to get into while some are not. In some. you can hop in from the side while in some of the others, you have to crawl in from the front. A military gore-tex bivy has a side zipper which allows you to get in from the side and then of course there are Bivvy’s which you can access from the side or you can crawl.
It’s very important that some weigh less than a pound which makes them ultra light. A military or a bivy made from Gore-Tex material is usually around 2 pounds or in some cases heavier.
That brings us to our next point when bivy’s came along the selling point was that they were ultralight weight. Since then things have changed along with the materials that are being used. Now, we are seeing tents that are ultra-lightweight; even lighter than a bivy. So, that selling point is no longer.
A key factor and the most important benefit to a bivy is that it allows you to set up very quickly in places where you couldn’t set up a tent; you could do it on a rocky face, you could do it next to a wall, you could do it in a place where tent stakes would not be able to penetrate the ground.
Pros and Cons of using of a Bivy
Since there’s a time and a place to use a bivy, there are pros and cons to using a bivy.
Pros of using a Bivy:
In the winter time, a bivy can add as much as ten degrees to your sleep system which is awesome. In the winter time you can go out for a zero degree trip. You can bring a zero Degree bag. You put this over your sleeping bag and now you have a negative ten sleeping bag. In other words you are going to stay warmer.
They block the wind extremely well. They are super easy to set up. If you see extreme weather coming in, you can hop in in a matter of seconds.
Another huge advantage of using a Bivy is you can set them up anywhere.
Cons of using a Bivy
With this type of gear there are many cons associated with them. So, you have to keep these in mind when planning your adventure.
First off, for rainy conditions they are not well suited as you will have to use a tarp with these because as soon as you open this thing up everything inside is going to get wet. There’s no way to crawl out of a bivy without everything on the inside getting wet.
Bivy’s can add ten degrees to your sleep system, in the summertime is a good thing. If you get hot you sweat with a bivy; this is a single wall tent that is essentially laying on top of you so condensation is a major problem with a bivy. It doesn’t really matter what type of material that you have because no material is one hundred percent breathable. If you are going to sleep in a bivy it doesn’t matter if it’s in the wintertime or if it’s in the summertime, the odds are you are going to wake up damp, your sleeping bag is going to be damped, the bivi itself is going to be damped.
This presents unique problems that you have to address and counts as a no big deal if you’ll be using your bivy for just a quick overnight trip. If it’s a multi-day trip, you have to take time, you have to dry your bag, you have to drive the bivvy sack as well. All of this takes time that takes away your adventure.
You have to think about bugs, if your bivy sack zips up 100%, no bugs but that means that your head is inside of the bivi and when you are inside of a shelter you’re breathing you are releasing moisture and that moisture will collect on the bivi itself. If your bivy sack doesn’t zip up 100% then you have to contend with bugs.
When you put in your sleeping bag inside of your bivy you crawl in you will realize and you will see just how tight and confined it is. Generally, with a bivy, there’s not enough room to put your gear inside of there you will have enough room in there for your cell phone and a battery pack.
If you love being confined and enjoy having limited space, you will love a bivy most people don’t like feeling that way and with that being said make sure to consider that before you go out and purchase one.
If you’re somebody who has always spent their time sleeping in a tent and having plenty of room, it can take quite a bit of time to get accustomed to sleeping in one of these.
The ultra lightweight bivvies can range from an easy sell of $20-30 whereas the expensive one’s made of Gore-Tex with military camos can cost around $250 or more.
In the wintertime, a bivy can be favorable to you as it can make your sleep warmer, blocks the wind, and even in the case of snowing under your tarp; bivy can keep you warm.
In the summertime, they’re too hot I tell you your body is releasing heat it’s releasing moisture you have your sleeping pad you probably won’t even have a blanket or a sleeping bag because that’s just too hot and if you sweat your sweat will gather on the inside of that bivy and make you even more damped.
There’s a place and a time to use them which can be for very very quick trips in dry arid environments.
I wouldn’t recommend using bivy for
- Thorough Hikes
- Summer time or humid areas.
- In the case of rain, use them with a tarp.
- You can use some of these without a tarp. Some are 100 percent waterproof but they are designed to be used with short duration rain events, not prolonged ones.