This photo shows the Sea to Summit Hydraulic Dry Pack during the testing process near a river.

Sea to Summit Hydraulic Dry Pack Review

- Field-tested -

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The Sea to Summit Hydraulic Dry Pack is a rugged dry bag with removable backpack straps. It’s particularly great for water sports like whitewater rafting or canoeing or kayaking adventures where portages might be necessary.

To get us a closer look, Sea to Summit sent Man Makes Fire a 120-liter review unit. After testing the Sea to Summit Hydraulic Dry Pack during a 7-day whitewater rafting trip on the Middle Fork of the Salmon River in Idaho, this is what we learned:

The Sea to Summit Hydraulic Dry Pack Basics

This photo shows the Sea to Summit Hydraulic Dry Pack with its backpack straps.
The Sea to Summit Hydraulic Dry Pack is a rugged dry bag with removable backpack straps for easy carry (120L version shown above).

The Hydraulic Dry Pack is Sea to Summit’s burliest dry pack, and the Australian company offers it in four core size options: 35-liter, 65-liter, 90-liter and 120-liter.

The heart of the Hydraulic Dry Pack is a roll-top dry bag with an oval-shaped base. Instead of being a uniformly round cylinder like most dry bags, the shape is a bit squashed. It turns out, I like this shape quite a bit because it makes packing and stowing the bags easier.

How so? When you’re filling the Hydraulic Dry Pack with gear and clothes, the interior shape gives you more options for odd-sized gear. For instance, a tent might not fit horizontally in a traditionally round dry bag of the same size — but it could fit horizontally in the Sea to Summit Hydraulic Dry Pack. This lets you add additional gear and clothing to best fill out the dry bag. This seems like a small feature, but I’m a big fan.

Here’s another benefit of the shape: When it’s time to carry the Sea to Summit Hydraulic Dry Pack, the oval shape also keeps the weight closer to your torso, making it easier to carry.

 

The Backpack Harness System

This photo shows the author wearing the Sea to Summit Hydraulic Dry Pack during the testing and review process.
The Sea to Summit Hydraulic Dry Pack backpack straps are comfortable and secure for carrying heavy loads.

The backpack strap system on the Hydraulic Dry Pack is very good. The straps are comfortable — and the entire pack system is super adjustable. You can adjust the height of the torso and fit of the sternum strap. And once you’re carrying a load, the load lifter straps let you dial in the ride.

For the bigger packs — the 65-liter and up — the padded hip belt lets you share the load with your hips. It’s not quite as good as a dedicated backpacking pack and hip belt system, but it’s surprisingly comfortable.

Sea to Summit did a nice job of maintaining excellent quality throughout, too: The nylon materials and stitching are great, as is the rugged aluminum attachment hardware.

Waterproof Dry Bag

This review photo shows the Sea to Summit Hydraulic Dry Pack with the backpack straps removed.
During our test on the Middle Fork of the Salmon River, we placed the Sea to Summit Hydraulic Dry Pack 120L in a mesh drop bag under the front seat. In this position, it was splashed through the self-bailing floor of the raft for seven days — no leaks!

If you completely remove the backpack straps, the Hydraulic Dry Pack turns into a standard dry bag. For our whitewater float trip on the Middle Fork of the Salmon River, we stowed a fully-loaded 120-liter Hydraulic Dry Pack underneath the front bench seat in a mesh Down River Drop Bag. This kept our gear — primarily clothes and down sleeping bags — out of the way.

As a testing situation, the mesh drop bag held the Hydraulic Dry Pack just above the self-bailing floor in our NRS Otter raft . . . and that meant frequent splashing every day for seven days. Incidentally, placing down sleeping bags in a near constantly wet situation is a bit of a high-risk move — if down sleeping bags get wet, they’re almost worthless to sleep in. The Sea to Summit Hydraulic Dry Pack inspires confidence with its build quality, so I took the risk.

Never once did the Sea to Summit Hydraulic Dry Pack leak during seven days of whitewater rafting.

Of course, you should know that most roll-top dry bags aren’t technically 100% waterproof because they can eventually seep if they’re fully submerged and under constant water pressure. For typical rafting, kayaking, stand-up paddleboarding or hiking in the rain, dry bags are practically waterproof.

Zippered waterproof bags like the YETI Panga Waterproof Duffel can often handle 30 minutes or so of submersion and might even achieve a waterproofness rating, but a quality roll-top dry bag properly rolled is just as effective. There’s a reason why roll-top style dry bags are the go-to choice for whitewater rafting trips — they’re easy to use and they work.

 

Size Option Specifications

The Hydraulic Dry Pack comes in four size options: Think of the 35-liter as a day pack, the 65-liter as a multi-day backpacking pack, the 90-liter has a week-long+ backpacking pack, and the 120-liter as a massive gear hauler.

The 120-liter is huge, and when it’s time to haul it, you’ll appreciate the backpack carry straps.

35-liter Hydraulic Dry Pack

Dimensions: 13″ x 8″ 28″
Weight: 2 lbs 4 oz

65-liter Hydraulic Dry Pack

Dimensions: 14″ x 10″ x 33.5″
Weight: 2 lbs 15 oz

90-liter Hydraulic Dry Pack

Dimensions: 16.5″ x 11.8″ x 39.5″
Weight: 3 lbs 7 oz

120-liter Hydraulic Dry Pack

Dimensions: 18.5″ x 12.6″ x 44.5″
Weight: 3 lbs 15 oz

Rugged Construction

The Hydraulic Dry Pack uses Sea to Summit’s 600D Hydraulic Fabric, which is also the burliest fabric in all of Sea to Summit’s dry bag and pack lineup. It has a three-layer construction of sorts: The middle is a 600-denier fabric that has a TPU laminated to both sides. By adding a fully-waterproof TPU layer to each side, you get a bit of extra waterproof protection. If an abrasion on the outside penetrates the exterior TPU layer, the interior layer will still protect your gear. Similarly if you pack the interior with gear that rubs the interior raw over time, the exterior TPU layer will protect the contents.

Sea to Summit says its fabric is also UV stabilized and won’t crack in cold weather. Compared to many heavy-duty dry bags and packs that feel sort of plastic-like, especially when they’re cold, Sea to Summit’s 600D Hydraulic Fabric feels more supple — which we like very much.

This photo shows the bottom of the 120L Sea to Summit Hydraulic Dry Pack.
The oval shape of the base makes carry easier, keeps the bag from rolling, and gives you additional packing options.

Competitive Alternatives & Options

If you’re looking for a large waterproof dry bag that doubles as a waterproof pack, here are several alternative options that might also meet your needs and interests:

NRS Bill’s Bag Dry Bag — The NRS Bill’s Bag blends a standard cylindrical dry bag design with removable backpack straps. It’s available in two sizes, 65 liters and 110 liters. One benefit is the extra secure roll-top strap system, which we like a lot. While the backpack straps are decent, they’re less rugged and comfortable than the Sea to Summit Hydraulic Dry Pack strap system — and do not include a hip belt.

SealLine Black Canyon Dry Pack — The SealLine Black Canyon Dry Pack is a rugged waterproof dry pack with permanently attached backpack straps. The biggest benefit of the Black Canyon Dry Pack is its comfortable, padded straps and hip belt. The biggest drawback is that the straps aren’t removable. The fabric is a rugged 600D polyurethane-coated polyester that feels a bit stiffer than the more supple Hydraulic Dry Pack fabric.

YETI Panga Waterproof Duffel — The biggest benefit of the YETI Panga Waterproof Duffel (see our full Panga Duffel review here) is that it has a duffel bag shape with a long zipper. This can make it easier to pack than dry-bag style packs that open from the top. While the YETI Panga Waterproof Duffel has removable backpack straps, they’re not as comfortable as the Hydraulic Dry Pack strap system.

The Bottom Line

The key thing to remember about the Sea to Summit Hydraulic Dry Pack is that while it’s a great waterproof backpack, you can also remove the pack straps and hip belt to transform it into a standard dry bag. We’re fans of this sort of versatility because sometimes you’ll want the straps for easy carry . . . but just want the bag for simple waterproof protection. Overall quality is outstanding, and the oval shape excels for both backpack carry and packing. Very highly recommended.

Get the Gear:

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Sea to Summit Hydraulic Dry Pack
Benefits
Rugged overall design
Comfortable (and removable) backpack strap system
Offered in four size options
Drawbacks
The 35-liter version doesn't have a supportive hip belt like the larger packs (but most people won't need one in the 35-liter size option)
4.8
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