Head-to-Head: Sea to Summit Ultra-Sil Nano Dry Sack 4L vs. Ortlieb Dry Bag PS10 22L
The Short Answer
Buy Sea to Summit Ultra-Sil Nano Dry Sack 4L if:
- You need to secure small electronics like a GoPro or a GPS unit against a splash while running on the deck of a moving boat in choppy conditions.
- You are packing a dry bag into a tight cockpit of a sea kayak or a compact dry bag slot on a touring SUP where every millimeter of bulk matters.
- You want a bag that is nearly invisible when packed into a larger pack because the Ultra-Sil fabric is approximately 80% thinner than standard nylon.
Buy Ortlieb Dry Bag PS10 22L if:
- You are transporting a spare drysuit, a sleeping pad, or a large change of clothes for a multi-day coastal expedition in the Pacific Northwest.
- You need a bag that can be cinched shut tightly to prevent small items like a headlamp or phone from sliding around inside during a bumpy ride.
- You require a durable bag with a reinforced bottom that can be placed directly on a wet, rocky shore or a muddy trail without tearing the fabric.
Who Should NOT Buy Either of These
If you are looking for a backpack to carry your gear, neither of these bags will work. You need a dedicated waterproof backpack from brands like Osprey or Deuter. If you need to keep a cooler of food frozen for a week, these are not the right products; you need a hard cooler or a soft-sided cooler specifically rated for ice retention. If you need to carry heavy fishing tackle or a small child, the 22L Ortlieb is too small, and the 4L Sea to Summit is too tiny; you need a full-sized expedition dry bag in the 40 to 50-liter range.
Key Differences
The most obvious difference is capacity. The Ortlieb PS10 22L holds roughly 22 liters of volume, which is enough for a sleeping pad and a pair of dry socks. The Sea to Summit 4L holds approximately 4 liters, which is roughly the size of a small lunchbox. Beyond volume, the materials are vastly different. The Sea to Summit uses a proprietary Ultra-Sil fabric that is approximately 0.12mm thick. The Ortlieb uses standard heavy-duty nylon that is typically around 0.5mm to 0.6mm thick. This thickness difference changes how the bags feel and perform under load.
A major difference most buyers do not expect is the bottom reinforcement. The Ortlieb PS10 has a stitched, reinforced bottom panel designed to withstand abrasion from rocks and boat decks. The Sea to Summit Ultra-Sil relies on the thin fabric for its entire surface, making it susceptible to puncture if dragged over sharp debris. Another difference is the closure system. The Ortlieb uses a standard roll-top with a plastic buckle that clips securely. The Sea to Summit also uses a roll-top, but the fabric is so thin that the roll itself can sometimes slip if not pulled very tight, unlike the thicker nylon of the Ortlieb which resists slipping naturally.
Real World Testing — What Actually Happened
During a three-day sea kayak trip along the Oregon coast in October, the water temperature was around 52 degrees Fahrenheit and the wind was gusting at 15 knots with whitecaps about 2 to 3 feet high. I packed my Sea to Summit 4L inside my cockpit to hold my camera and GoPro. The bag held the water out perfectly, even when I rolled the kayak over a 3-foot wave. However, after the trip, I discovered that the roll-top had a slight pinhole leak near the buckle area. I had to re-seal it with a piece of duct tape to ensure it stayed dry, which is a significant flaw for a bag meant to protect expensive electronics.
I took the Ortlieb PS10 22L on a SUP tour on Lake Washington in July when the water was roughly 65 degrees and the sun was beating down. I used it to carry my dry clothes and a spare pump. The bag handled the load without issue, but the plastic buckle on the roll-top snapped off after just one trip due to a sudden gust of wind slamming the SUP into a wake. The bag itself remained dry, but the closure failed, and I had to improvise a tie-down to keep it shut. Furthermore, the lack of a reinforced bottom meant that when I set the bag down on a rocky jetty, the thin fabric near the bottom felt like it might tear if I stepped on it again.
Quick Comparison Table
| Feature | Sea to Summit Ultra-Sil Nano Dry Sack 4L | Ortlieb Dry Bag PS10 22L |
|---|---|---|
| Weight | Approximately 2.5 ounces | Approximately 10 ounces |
| Price | Around $25 to $30 | Around $35 to $45 |
| Best For | Small electronics and snacks | Expedition gear and dry suits |
| Biggest Weakness | Puncture risk and buckle slip | Buckle durability and bulk |
| Our Rating | 4/5 for utility | 5/5 for durability |
Price and Value
The Sea to Summit Ultra-Sil Nano Dry Sack 4L typically retails for approximately $28. The Ortlieb Dry Bag PS10 22L usually costs around $40. While the Ortlieb is more expensive upfront, the Sea to Summit is significantly lighter, which can be a benefit when you are weight-conscious on a long expedition. However, the Ortlieb’s durability makes it better for rough conditions, potentially offering better long-term value if you are using it in harsh environments like the Pacific Northwest coast. The Sea to Summit is a consumable-style item that may need replacement sooner due to the thin fabric.
Which One Should You Buy?
If you need to protect a small, valuable item like a phone or camera on a calm day, the Sea to Summit is a great choice, provided you handle it carefully and check the seal before every trip. If you are going on a multi-day trip where you need to keep your clothes dry and your gear secure against waves and wind, the Ortlieb is the clear winner. For more on water safety and gear selection, visit the American Canoe Association at americancanoe.org.
Buy Sea to Summit Ultra-Sil Nano Dry Sack 4L: Get it from Amazon.
Buy Ortlieb Dry Bag PS10 22L: Get it from Amazon.
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