Made by Filson: See Filson dry bags on filson.com
The Filson Dry Sling Pack is a 20-liter waterproof sling bag made from TPU-coated nylon with welded seams. It is built for anglers who want a roomy, dry pack they can rotate to the front without taking it off. Filson is the maker. FFIP score: 8.1/10.
Overall: 8.1/10 | Badge: Highly Recommended
Verdict: A big, waterproof sling that keeps my fly boxes dry.
Best For: Boat, raft and bank anglers who want a roomy waterproof sling for layers, a lunch, electronics and a few boxes.
Not For: Anglers who want a light, small chest-style pack, or who need lots of internal pockets.
Pros
- 20 liters of waterproof storage in a sling format, per Filson.
- RF-welded seams and a TPU-coated nylon shell, per Filson's dry bag materials page.
- Padded back panel and an extra-wide shoulder strap for carrying a real load.
Cons
- The main zipper is a stiff waterproof design and takes effort, per independent review.
- Little internal organization, per independent review.
- Size: a 20-liter sling is a lot of pack on one shoulder.
The FFIP Scorecard
| Criterion | Weight | Score | Why |
|---|---|---|---|
| Organization/access | 25 | 7 | Roomy, but the inside is mostly one big space, so I dig a bit. |
| Comfort/carry | 25 | 8 | Rotates around for quick grabs; the single wide strap pulls on one shoulder when full. |
| Weather protection | 20 | 9.5 | Where it shines: it ignores spray and a wet seat on a cooler lid. |
| Durability | 15 | 8.5 | Coated fabric wipes clean and looks the same after a season on a boat. |
| Value | 15 | 7.5 | Priced like a Filson, but it holds up for a bag that lives in a boat. |
| Overall (weighted) | 100 | 8.1 |
How Is the Filson Dry Sling Pack Built? The Engineering Behind It
Nylon tarpaulin with a TPU coating
Filson says its dry bags are made from nylon tarpaulin with a TPU (thermoplastic polyurethane) coating, which it describes as resistant to punctures, abrasion and UV light. In plain terms, the fabric is a woven nylon base that gives strength, and the polyurethane film on the outside makes it waterproof. PackHacker's review lists the Dry Sling Pack at 840D nylon with a clear ether TPU exterior. Ether-based TPU is the type known for holding up to moisture, which matters for a bag that lives in a boat. The outer surface wipes clean, which you can see in our photos: the olive finish carries a bit of dust and still looks like the same bag.
RF-welded seams
Filson says the seams on its dry bags are radio-frequency (RF) welded, the same method used to build whitewater rafts, and that the weld produces a durable, flexible bond that is stronger than the original fabric. How does that work? An RF welder passes a high-frequency electric field through two layers of coated fabric, which heats the plastic coatings until they fuse into a single piece. There is no thread and no needle hole, so water has no path in. For anglers, the benefit is simple: when the bag sits in the bilge, rides on a wet cooler or gets splashed on a rapid, the seams are not where the leaks start.
The zipper and the access
PackHacker's review says the main compartment uses a TIZIP waterproof zipper that opens along the left and bottom sides, with a YKK AquaGuard zipper on the front secondary compartment. A waterproof zipper presses sealing lips together along its length, so it is stiffer than a regular zipper. The front pocket is only highly water resistant, per the same review, so keep wallets and phones in the main compartment. That side-and-bottom opening also means you pack the bag differently, and the reviewer notes items must be packed in an upside-down fashion. I load mine by tossing in layers, lunch and electronics; it all fits, but with one big open space I have to dig a bit for the small stuff.
The sling geometry
Filson describes the Dry Sling Pack as a 20-liter bag designed for anglers who need access to gear on their back without removing the pack, with an extra-wide shoulder strap for comfort. When the side-stabilizing strap is unclipped, the bag rotates to the front. That clip is the clever bit: a clipped stabilizer keeps a loaded bag from swinging while you walk or row, and an unclipped one lets it slide to your belly for access. PackHacker lists a padded back panel and shoulder strap with breathable mesh, a top handle with buckle, a side grab handle, a front D-ring, attachment loops and a zippered mesh pocket on the back wall. The D-ring and loops are visible in our photo.
Size and weight
PackHacker lists the pack at 20 x 9.5 x 7.25 inches and 1.8 pounds, which makes it a day-pack-sized sling. Compared with a 13-liter sling, the extra volume buys you a layer, lunch and a spare box. The pack I carry is the olive Dry Sling Pack in the 20-liter size, and the dimensions above are PackHacker's numbers.
On the Water with the Filson Dry Sling Pack
This is the Filson Dry Sling Pack in olive, 20 liters, on a river float on the Smith River on a bright summer day. Rocky, pine-covered cliffs rose on one side and tall green grass lined the bank, and our rafts were pulled up on the shore while we rigged up. The water was flat and green, the day was warm, and big clouds were building with some sun breaking through, the classic summer setup where weather could be on the way.
That was one day of a ten-day trip, and it rained a lot. We still got into a lot of fish. I have been running this pack for a few seasons of float trips, roughly 10-15 days a year.
The moment it earned its spot came at lunch. We pulled over, and the Filson was riding on the cooler lid next to my Lid Rig box. Given that it rained nearly every day of that trip, I was super happy to have something that was extra waterproof.
A cooler lid is where a dry sling lives on a float: out of the bilge, within reach, and ready to swing onto your shoulder when you pull in. For more on setting up a boat, see drift boat tips 101 and the captain's position.
How Does the Filson Dry Sling Pack Score, Criterion by Criterion?
Organization/access (Score: 7/10)
Organization is the Filson Dry Sling Pack's honest trade-off. You get a large main compartment, a front secondary compartment and a zippered mesh pocket on the back wall, but PackHacker notes there is no internal organization in either compartment. That works if you use pouches and boxes inside. A magnetic box like the one in our photos helps, since it keeps flies in one place. I throw layers, lunch and electronics in and it all goes, but the inside is mostly one big space, so I have to dig a bit.
Comfort/carry (Score: 8/10)
Comfort and carry come from the padded back panel and extra-wide shoulder strap, with breathable mesh, per PackHacker. The side-stabilizing strap keeps the load from swinging. At 20 liters it is a lot of pack on one shoulder, so how heavy you load it matters. The pack rotates around so I can grab things without taking it off. On a long day the one wide strap is fine, though a full pack does pull on one shoulder.
Weather protection (Score: 9.5/10)
Weather protection is the reason to buy: nylon tarpaulin with a TPU coating, RF-welded seams and a TIZIP waterproof main zipper. This is where the pack shines for me; it sits on a cooler lid in a raft and does not care about spray or a wet seat. Filson says its dry bags are 100 percent waterproof, and PackHacker says the front compartment is only partly waterproof, so use the main compartment for anything that cannot get wet.
Durability (Score: 8.5/10)
Durability starts with the fabric and the welds. Filson says the coating resists punctures, abrasion and UV light. The zipper is the part to look after. In my experience the coated fabric wipes clean, and the olive shows dust but not damage. After a season on a boat it looks like the same bag.
Value (Score: 7.5/10)
Value is the Filson Dry Sling Pack's softest score. It is priced like a Filson, so it is not cheap, but for a bag that lives in a boat I think it holds up. Judge it against the other waterproof slings in the comparison, and consider how much volume you actually need.
Who Should Buy the Filson Dry Sling Pack (and Who Should Skip It)?
Buy the Filson Dry Sling Pack if you want a waterproof pack with room for a layer, a lunch and your electronics, and you spend your days in a raft, drift boat or on a river bank. It suits anglers who like to keep gear within reach on the cooler or at the oars. For a boat day checklist, read how to organize for your next trip.
Skip it if you want a small pack that rides close to your body, or you want a lot of internal pockets. A 13-liter sling or a vest is lighter on the shoulder and easier to organize.
How Does the Filson Dry Sling Pack Compare?
The Fishpond Thunderhead Submersible Sling is the closest competitor in this review series.
| Feature | Filson Dry Sling Pack | Fishpond Thunderhead Sling |
|---|---|---|
| Capacity | 20 L (per Filson) | 13 L (per Fishpond) |
| Weight | 1.8 lb (per PackHacker) | 1.8 lb (per Fishpond) |
| Main zipper | TIZIP waterproof (per PackHacker) | TIZIP waterproof (per Fishpond) |
| Price (per maker site) | See Filson | $269.95 |
The weight is the same on paper, so the 20-liter bag gives you more volume for the same carry. In my scoring the Fishpond edges it, 8.3 to 8.1, with the Thunderhead ahead on organization and durability and the Filson ahead on value.
Our Pick in the FFIP Shop
The Filson Dry Sling Pack is not in the FFIP Shop. Our pick is the Nirvana waterproof sling pack (7.5 L), an IPX-7 rated sling that weighs 1.24 pounds and lists at $89.99 in the shop at the time of writing. It holds far less than the 20-liter Filson, so pick it for light days and the Filson for a full load. Stock changes, so check the page.
Frequently Asked Questions
How big is the Filson Dry Sling Pack?
Filson describes the Dry Sling Pack as a 20-liter bag. PackHacker lists it at 20 x 9.5 x 7.25 inches and 1.8 pounds. Mine is the olive, 20-liter version.
Is the Filson Dry Sling Pack waterproof?
Filson says its dry bags are made from TPU-coated nylon tarpaulin with RF-welded seams. PackHacker reports a TIZIP waterproof zipper on the main compartment and a YKK AquaGuard zipper on the front compartment, which is only water resistant.
How does the Filson Dry Sling Pack rotate to the front?
Filson says the bag rotates to the front for easy access when the side-stabilizing strap is unclipped. Clip the strap when you walk or row and unclip it when you want to reach in.
Does the Filson Dry Sling Pack have a lot of pockets?
It has a main compartment, a front secondary compartment and a zippered mesh pocket on the back wall, per PackHacker. The review notes that there is no internal organization, so many anglers use small pouches or boxes inside.
Final Verdict
The Filson Dry Sling Pack is a good bag for rafts and drift boats. It stays dry, stays put and stays out of the way. Just know it is more of a big dry bucket than an organized pack.
Christian's Pro Tip: Park it on top of the cooler where you can reach it from the rower's seat. Put the rain jacket in last so it comes out first.
Tight lines, everyone!
