Waterproof/Modular Messenger Bag Ideation Sketches

this is for a project, i am now looking to refine the design to become a little more simple, and am exploring other options to make the bag fully rainproof, ie: having no gaps that rain could find itself into when the bag is closed.

open to critique on the design as well as sketching, and definitely looking for more exploration and ideas on creating a better more eye pleasing modular system.

and a few more…

Chrome already uses this exact attachment method. It works very well for bicycle use, but for other uses it become a bit cumbersome.

I have this bag, and have thrashed the crap out of it for 3 years commuting/riding to work. Its a thing of beauty. I can bring my work to the office, leave it there and pick up a 6 pack on the way home.

And square bags are very uncomfortable to wear, unless they have some padding where your laptop sits.

Good start on the sketches though. But, the idea is exactly how a chrome bag works, right down to how it sits on your body.

i have done my research on bags, and i am very aware of chrome. I know a few people who have had them, and have read these reviews pretty throughly

my goal is not necessarily to create something revolutionary (although this is never a bad thing, and i could use some help im sure), but i want to create something that works. I also like the shape in which the chrome bags open and flap, they create a good rain stopping measure.

If you have any input on what you like and dont like about your bad i would love to hear that too.


The chrome is definitely a good model to follow as far as function. I like the shoulder pad sewn into the strap instead of the removable type a-la Timbuk2 and Crumpler bags I also have. They never seem to be in the right place. Also, the use of seatbelt strap material is more comfortable than the heavy nylon type (again a-la Timbuk2 and Crumpler)

I use the Crumpler as a more professional looking bag if I’m traveling or going to meetings, I use the Chrome as an every day tool. The wife has a Timbuk2 because “it’s cute!” so I don’t have as much of an opinion on that aside from not fitting as well on the bike vs. Chrome.

I apologize but I see nothing in your sketches to suggest “Rain proof”. IMO if your are working the angle of making something rainproof two things: one make it look rain proof and really make it rain proof.

Good “water resistant” and “leak resistant” “messenger” bags such as the Chrome bags have overlapping flaps, reinforced double turned seams, and water proof “floating liners” meant to keep the wet away from the cargo. In addition the classic Musette construction(commonly mis-marketed and mis-referred to as “messenger”) does not lend it self to actually resisting or preventing water from entering the bag when worn over the shoulder and along the back.

Chrome bags do as well as they can to keep water out but that is more due to their over built, triple reinforced, independently lined leak proof construction as opposed to being due to the materials and pattern. (IMO they are over priced, over built, over heavy and over hyped but pretty damn bombproof nonetheless,… and I own two.)

Off the top of my head you may wish to check out Sealline,

and Ortleib

both are noted for the waterproof construction…to the point of being almost over the top comical in their styling

The aspiration to modularity is notable but I know of three patents you’re currently stepping on with the velcro and webbing “micro bags” attachments on the interiors.

Maybe you want to make it a little more specific rather than a be all, “everything including the kitchen” sink bag.

But, IMO, thats the appeal of the messenger bag: its ridiculously useful for carrying everything from laundry and a laptop to a 16 pack of Surly Pint Cans on ice (or if yer a hipster on yer fixie, a 24 pack of PBR… :unamused: )

as long as the revolution is incremental I think you’ll be OK. But there are literally THOUSANDS of bags out there that look and work like that already.

Are you looking at the fixed gear trend as an inspiration for your own project and on its perceived “simplicity” as the purpose and function? I ask that because that trend and its participants are very eccentric and by their own purpose and definition, fixed, on a specific look and lifestyle. Meaning: its not about the bag’s performance as much as its about the rider’s “performance” while wearing the bag in the context of the look and lifestyle.

What I dislike about Chrome bags:
–too heavy, full or empty
–over built
–unforgiving with odd sized cargo with hard edges
–no padding for me or my gear except on the shoulder
–poor ergonomics: with typical over the shoulder wear bag weight is not evenly distributed and shoulder goes numb after a bit on my back
–too hot. It traps heat radiating off my back making me and the bag, stinky and sweaty
–not enough smaller pockets to deal with smaller stuff (keys, camera, fuzzy bits, tools, repair kits, etc)
–Waterproof tarpulin lining not really water proof and gets dirty quickly
–dislike using the flap to access the bag when its on me.
–hate to take the bag off to use the flap to access the bag.
–only available in left sling
–no way to attach LED blinker or any other gear on exterior for night riding
–everyone and their grandmother has one

That was actually quite helpful.


I want to do a ‘messenger bag’ because i find myself wearing my backpack alot, and i want easier access to my belongings without taking my backpack off. I like that you can sling the bag to your side and access the compartment without taking the bag off.

One thing that i would argue has not been done thousands of times is bags that incorporate a modular system where an almost endless variety of smaller compartments can be made and attached.

recently i was thinking about experimenting with some sort of waist strap that could be used if the bag is being worn for a long time.

I am absolutely in the planning stages of this project.

I am also more interested in why the inner liner isn’t totally water proof, and how well the flap system keeps out rain.

again, the info is quite helpful.

the waist strap has also been done…
but it is quite effective.

there is no patent or anything on having a waist strap, so there is plenty of room for innovation and improvement in that department

I would recommend adding one regardless,
it prevents the bag from bouncing on your back when running.
also takes pressure load off of your back and shoulder.

I’ve ridden my Chrome through many a rain and snowstorm and haven’t gotten any papers wet. Its all in how you pack it. That doesn’t mean I can drop it in a lake and have it stay dry. There’s a difference between waterproof and water tight. Ortlieb does a great job with that, and one of chrome’s backpacks does as well.

It just makes it tougher to access your stuff quickly.

The waist strap works best with heavier/larger loads. The cross chest strap works best with every day use. It does still move around however, so its not totally perfect. There’s room for improvement/innovation there for sure.

Ive got a bunch on my plate, but you have all given me more ideas. More sketches/ideation to come soon!!!

The flap is pretty good in keeping out water and rain due to the flap being larger than the opening of the bag with pretty much any load, empty or full in it. it does leak on the left edge near where the shoulder strap attached to the bag when its on your back. But as long as you make sure its not folded funny when you close it, its pretty darn good for keeping rain out.

FYI: the DeMartini/Globe Canvas Co original messenger bag from the early 80’s (made famous in the movie “Quicksilver”…) was the first bag to use that overlapping flap with a slide adjust buckle on a 2" PP webbing strap…Chrome, RE-Load, Manhattan Portage, Stuart Crumpler, etc. appropriated it, made it their way and made it better.

The inner liner is stitched and taped PVC tarpulin. The taping used is only a PP webbing and therefore will leak if you put enough water in it. it does well repelling moisture and wetness when the exterior Cordura gets soaked, but if you did like i did once, thinking i was really cool, and pour 5 lbs of ice and use it as a cooler, it will leak, thru the lining seams and Cordura seams, down your back, take for ever to dry and stink in the process.

My comment about “thousands of times” was about the basic mussette construction, not the modularity. if thats your goal there are better patterns to use/experiment with, to enable the bag to open better so you can really make it modular and everything removable with ease.

ok, here are my updated design goals.

-main compartment easily accessible without taking bag off
-versatility / (modularity?)
-waterproof (rainproof)
-distributes load over more surfaces than a single shoulder.

as far as modularity goes ideas for ‘modules’ so far are:

-laptop sleeve
-waterbottle holder
-camera case
-artsupplies/pencil case
-misc. smaller removable compartments

some ideas are coming to mind, and will be posted as soon as i can translate them to paper.