Initial Review – Sea to Summit Ultra-Sil Dry Sack

Review Date: May 15, 2006

Name: Pat McNeilly
Age: 43
Gender: Male
Height: 5’ 8” (1.7 m)
Weight: 165 lb (75 kg)
Email address: pmcneilly@osophs.dhhs.gov
City, State, Country: Gaithersburg, MD, USA

Backpacking Background:
I have been hiking for at least 20 years but backpacking for only the last three years.  Most of my backpacking is done as overnight trips and occasional weekend and weeklong trips.  My typical packweight is approximately 18 to 20 lb (8 to 9 kg) before food or water.  Most of my backpacking is the three season variety in the mountains of Maryland, Virginia, and West Virginia.  In addition to backpacking, I also fish, hunt, and have been involved in disaster relief.  As a result, some of my backpacking equipment gets use in a number of different venues.

Product Information:

Product: Ultra-Sil Dry Sack
Size: 13 Liter (793 cu in)
Manufacturer: Sea to Summit
Year of Manufacture: 2006
Color: Light Blue
URL: http://seatosummit.com
MSRP: Not listed

	As listed	As measured
Weight	1.4 oz (40 g)	1.3 oz (37 g)
Length	21 in (53 cm)	21 in (53 g)
Diameter at base	8.5 in (21 cm)	8 in (20 cm)
Diameter at opening	12 in (30 cm)	12 in (30 cm)

Product Description (as described on the manufacturer’s website):
According to the manufacturer’s website, the Ultra-Sil Dry Sack is made of a Siliconized Cordura material, which is a waterproof nylon fabric.  The manufacturer goes on to say that Ultra-Sil nylon is a polyurethane coated Siliconized Cordura which allows for better waterproofing and greater durability.  Ultra-Sil Dry Sacks are reported to be more than 50% lighter than other popular dry sacks.  The product uses a Hypalon roll top closure with a stiffener at the top for a watertight seal.  The material has a slippery feel for easy packing and is nearly transparent or viewing the contents of the bag.  The manufacturer indicates that the seams are double stitched and taped.

Product Review:
The Ultra-Sil Dry Sack arrived in a standard Tyvek shipping envelope.  Inside, the product was stored in a multi-color rigid plastic package which measures 14 in (35.5 cm) by 2.5 in (6 cm).  A portion of the packaging is clear and allows the color of the dry bag to show through.  The packaging is quite impressive with color photos and large bold type.  The package also has a sticker on it to indicate that the product was awarded a Backpacker Magazine Editor’s Choice Award for 2006.  The back of the packaging includes a description of the product in five different languages (English, German, French, Spanish, and Japanese).

The Ultra-Sil Dry Sack is constructed of a Cordura nylon fabric with a ripstop type pattern throughout the material with a Sea to Summit logo 8.5 in (21 cm) from the top edge of the bag.  The material is coated and does have the slippery feeling described by the manufacturer.  The top opening has two edges with one having a black 12 in (30 cm) by 0.75 in (1.9 cm) strip of Hypalon (a synthetic rubber material) sewn to it.  The opposite edge has a 12 in (30 cm) by 0.75 in (1.9 cm) plastic stiffener sewn into a slot formed by the bag material being folded on itself.  On either end of the opening and attached directly to the Hypalon strip are the two pieces of a 0.75 in (1.9 cm) side-release buckle.  The bag has a single side seam as well as a seam attaching the material forming the round bottom.  These seams are double stitched and taped.  The seams around the opening are not taped but the Hypalon strip is intended to be folded over which should provide a waterproof seal.

The product has a tapered appearance from top to bottom when the bag is empty, with the top opening being 12 in (30 cm) wide while the round base is only 8 in (20 cm) wide.  On a small card inside the packaging (written in six languages, add Dutch), the manufacturer indicates that the top must be folded at least three times with excess air expelled to ensure a waterproof seal.  This folding from the top along with clipping the buckle produces a more cylindrical shape when the bag is full.  When I fold the top as recommended with the bag filed with air a tight seal is produced when the bag is squeezed.  Since the coating on the bag is slippery, excess air in the bag may allow for the closure to slide and not seal properly.  The small card with the product does indicate that the bag will keep objects dry in any situation where the bag is not submerged.  I plan to test the seal for air-tightness when the bag is full and when it is not.

The manufacturer states that items can be seen through the fabric.  I have found that if I hold something directly against the fabric, I can actually see through it.  I find that I can locate an item inside the bag by its color but need to hold it against the fabric to see it clearly.  I find this adequate at this point but will look closer at this during the test period.

Since the bag has a slippery feel, I have found myself carrying the bag by the top.  After the top is folded and clipped, the loop created makes a natural handle for the bag.  I am not sure of this would lead to problems later on in terms of added strain on the bag (particularly with a heavier load).  This might be something to watch for during the test.

Test Plan:
I plan tot use the Ultra-Sil Dry Sack on any backpacking trips I take during the test period.  I will also plan on using the bag as a pack liner for my smaller lumbar and daypacks.

I plan to look at how well this product keeps moisture out through a series of tests using a large tub of water.

●   Does the top have to be rolled down tight to seal adequately?
●   How much water enters if the bag is submerged?

Durability of the bag could be an issue and I plan to investigate the following:

●    How well does the bag handle normal abrasion?
●    Can the bag handle objects with sharp edges?
●    Will the seams and their taping show signs of stress from being packed too tightly? 
●    Does air trapped in the bag play a role in stressing the seams?
●    Does the Hypalon strip wear after repeated use and allow for an inefficient seal?
●    Can the plastic stiffener pierce the nylon fabric?? Could it become lost of this happens?
●    Does the buckle remain closed?  How easy is it to release the buckle?
●    Does the fabric degrade or become more opaque after being exposed to sunlight?

Some other things that I want to investigate include:

●    Will the bag’s coating help with loading and unloading it from a pack?
●    How well can I visualize items inside the bag in dark conditions?
●    Is it better to have the bag full when closing or is it difficult when half full?
●    Can I fit a sleeping bag into the dry bag?
●    How useful is the bag for other purposes such as hauling water or washing out clothes?

Summary:
The Sea to Summit Ultra-Sil Dry Sack is a very light weight item that appears to be sturdy, and well constructed.  I am impressed with the sealing mechanism which folds easily and creates what seems to be a very air tight seal.  I am most impressed with the fabric of the bag which looks to be quite strong and which also allows me to identify items inside the bag.

Things I like:

    1. Light weight
    2. Transparent fabric
    3.  Simple closure system

Things I don’t like:

    Nothing at present

I would like to extend my sincere appreciation to Sea to Summit and BackpackerGearTest for the opportunity to test this product.