If you're headed to a rainy city, that means you should buy a waterproof backpack, right?
Not necessarily. A water-resitant backpack may be just what you need.
Waterproof Means Submersible
If a backpack is labeled waterproof, that means you can completely submerge the bag in water without letting moisture inside. Waterproof is more about being underwater than about being in the rain.
Waterproofness is for extreme conditions, not a light drizzle.
You can walk through a waterfall or whitewater raft down a river with a waterproof backpack, and your stuff will stay dry.
To clarify, backpacks made with waterproof materials are not necessarily waterproof backpacks. A fabric can be waterproof. A zipper can be waterproof. And yet, a backpack made with waterproof fabrics and waterproof zippers may be classified as "water resistant" - not fully waterproof.
Few travel situations require a truly waterproof backpack. Extreme water resistance, like what you'll find in the Outbreaker Collection, will excel for most trips. Especially city adventures.
The Downside of Waterproof Bags
Creating a waterproof bag, one that keeps your stuff dry when you submerge the bag in water, is a huge endeavor.
Designers have narrow options and have to make sacrifices in the pursuit of waterproof. Every material needs to pass a submersion test, and the components must be assembled in a way that doesn't create holes. The standard process of sewing fabric creates holes for water to seep through with every stitch. Those holes are too minuscule to impact your travel backpack's performance in a rainstorm, but do matter if you submerge a bag in a lake.
Most companies approach waterproof assembly by welding thermoplastics - essentially melting two pieces of fabric together using ultrasonic sound waves.
Welding is an expensive way to make a backpack, and it requires very particular fabrics. Not every fabric can be welded. For that matter, many waterproof fabrics cannot be welded and therefore cannot be made into a truly waterproof bag. To top it off, waterproof bags also must be simpler in design than sewn bags due to the limitations of welding. That's why most are designed as a bucket-like main compartment with one or two flat pockets. Your choices in aesthetics and functionality are limited with a waterproof bag.
This would be terrible for a travel backpack. You’d be sacrificing organization, packability, and features for a level of water protection you just don’t need for most travel.
Waterproof backpacks are great at keeping water out when you're kayaking down a river, but the strict limitations in materials and assembly make them unideal for most travel circumstances.
So, what does water-resistant really mean?
The short answer: it depends. Unlike "waterproof," which has a clear definition for bags, water-resistant is a little vague.
A water-resistant backpack might only keep your stuff dry in a drizzle, or it might perform well in a downpour. To understand where a backpack falls in that spectrum, check for two main factors: zippers and fabric.
If you see coated zippers on a backpack, that's a clue your bag will perform well in heavy rain. Coated zippers keep water out of the bag in one of the most vulnerable places, since zippers are full of holes.
Fabric is a little more complicated. Some "water-resistant" fabrics are simply tightly-woven nylons with a durable water resistant (DWR) coating applied to the back. No matter how tightly you weave a fabric, there will always be holes. Holes mean water gets through. Cheaper fabrics combat this issue with a coating to repel moisture. That coating works for a while... but it's infamous for rubbing away over time.
Higher-quality waterproof fabrics, like VX21 sailcloth, have multiple layers to trap moisture and keep coatings from wearing off. Tortuga travel backpacks have both a layer of waterproof PET film and a weather-resistant coating. It'll keep your stuff dry, even if you're stuck in a downpour.
As its name implies, sailcloth was originally used for the sails of racing boats and is made to stand up to extreme conditions. Sailcloth is a premium fabric choice for maximum performance and durability. If you see "sailcloth" or multiple waterproof layers in a backpack's fabric, that's a clue that your stuff will stay dry in heavier rain.
The Bottom Line
A high-quality, water-resistant backpack will keep your stuff safe and dry in a rainstorm. If you throw a water-resistant backpack into a lake, however, your laptop may not fare as well. If you're kayaking, bring a truly waterproof dry bag.
The Outbreaker Backpack is a water-resistant, carry-on-sized backpack designed for city travel. You can learn more about the advantages of a waterproof fabrics and all the other travel-optimized features built into the Outbreaker Backpack.
This post will teach you about the difference between waterproofing and water resistance. Backpacks made with waterproof materials are not necessarily waterproof backpacks. A high-quality, water-resistant backpack like the Tortuga Outbreaker will keep your stuff safe and dry in a rainstorm.