Long Term Report – Sea to Summit Ultra-Sil Dry Sack



Review Date: September 13, 2006

Name: Pat McNeilly
Age: 43
Gender: Male
Height: 5’ 8” (1.7 m)
Weight: 155 lb (70 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 in³)
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 for viewing the contents of the bag.  The seams are double stitched and taped.

Field Conditions:  
I have continued to use this product on a range of trips including trips on the Appalachian Trail in Pennsylvania and in the White Mountains of New Hampshire.  I also used this product on dayhikes in Acadia and Shenandoah National Parks, as well as hikes near Washington, D.C.  The elevation on these trips varied from 200 ft to 6300 ft (60 m to 1900 m).  The temperatures I encountered on these trips ranged anywhere from 48 F to 87 F (9 C to 30 C).  I have used the sack in all types of conditions including light mists, fog with strong winds, and heavy downpours.  I even took it along one day on a hunting trip to help keep ammunition dry.

Product Review:
Since my Field Report, I continued to use the Ultra-Sil Dry Sack as much as possible.  I wanted to see how it would hold up to a good amount of abuse.   I have tried not to be too hard on the sack since the manufacturer does caution about too much abrasion and exposure of the fabric to excess amounts of sunlight.  After a few months of use I can say that I have not had a single item get wet while it was stored in this product. 

The sack has held up well in the course of the test and looks almost as it did when I received it.  There are no visible abrasions on it despite continually sliding it in and out of packs and across various zippers.  I would close the bag and expel air with the bag on bare ground and even on exposed rock at times.  There is no evidence of wear along the seams and the taping appears to be intact.  I have not noticed any fading of the color or evidence of the fabric becoming opaque after being exposed to sunlight.  The buckle provides a secure closure yet releases very smoothly and has not shown signs of wear. 

The Hypalon strip on the closure has wrinkled a bit with use but this has not affected the sack’s ability to seal properly.  I have not had any problems with the seal wearing.  In my earlier reports I had concerns about the plastic stiffener causing wear near the seal.  This has turned out not to be a problem. 

I have found that it is best to load the sack prior to sliding it into a pack.  This avoids having excess air in the sack which could take up unnecessary volume inside the pack.  The coated fabric allows the sack to easily slide in or out of even my most overloaded pack. 

One minor problem I have encountered is that the plastic stiffener along one edge of the seal tends to fold in on itself which then requires fully extending the sack to ensure that stiffener will align with the Hypalon strip before closing the sack.  This is only a minor inconvenience since I typically wanted to make sure the sack had a good seal.  Only during times that I was in a hurry and wanting to close things up quickly did this really present a problem.

Part of my test plan included evaluating alternative uses for the Ultra-Sil Dry Sack.  During one trip I attempted to fill the bag with air and close the seal tight, then use the inflated bag as a pillow.  This did not work out too well since I found that over approximately a 10 minute time that the sack slowly deflated and I would then need to add more air.  This left me a little perplexed since the sack did seem to be air tight. 

I also attempted to use the sack for hauling water.  I filled the sack approximately one third full and loosely closed the top.  This seemed to put a great deal of strain on the closure which I was not very comfortable with for any length of time.  While I had water in the sack, I noticed that the outside of the sack was wet.  I initially thought this was due to the filling process.  After wiping the outside of the sack with a towel I noticed that the sack was still wet.  Small droplets were forming on the surface of the sack.  It appeared that there must be small holes in the fabric which allowed the water to flow out.  I do not notice any wear of the material when the sack is dry but tiny abrasions are very possible after using the product for the entire test period.  None of the leakages appeared to be associated with the seams which appear to be going strong.  This caused me to repeat some of the tests I conducted and mentioned in my Field Report.  This included submersing the dry sack (filled with clothing) in my bathtub.  Some water did get into the sack even though there seemed to be a tight seal.  I noted that the water entering was not coming from around the seal but rather from an area on the lower one third of the sack.  When I performed this test for my Field Report water did not get into the sack.  When I exposed the filled dry sack to the full force of my home shower, I did not notice any water getting to the inside.  These results, although somewhat contradictory, give me some confidence that the Ultra-Sil Dry Sack will still protect my gear despite having some tiny holes in the fabric.  I must note that the manufacturer does state in the packaging that the sack should not be submerged and that the user should be careful to avoid abrasion. 

I have continued to use the Ultra-Sil Dry Sack with hard sided or sharper items including my stove.  The fabric has held up even with these items and I have not had anything poke through the material.  However, as I noted in earlier reports, I don’t have confidence with the thin sil-nylon and sharp edged items. 

Summary:
The Sea to Summit Ultra-Sil Dry Sack is a very light weight item with a sealing mechanism that folds easily and creates a very water tight seal.  The fabric of the bag appears to be durable and strong but needs some care to avoid abrasion.  The transparent nature of the sack allows me to identify items inside the bag without difficulty.

Things I like:

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

Things I don’t like:

    1. Difficult to expel air when partially filled
    2. Plastic stiffener tends to fold inside bag 
    3. Need to avoid abrasion

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