Just how waterproof is waterproof?

6 thoughts on “Just how waterproof is waterproof?”

  1. It’s now 4 years later (since the original post was posted). Hopefully someone’s still tending this blog …..
    I’ve got a pretty tight budget so I have to be very judicious in the products I choose. I’m leaning towards the S2S ultra-sil tarp-poncho but wonder how waterproof it is vs the nylon one. If one has to walk in a heavy rain, will the ultra-sil really keep the rain out or will it start to seep through after a while?

    Any advice would be much appreciated. Thank you.

    1. G’Day –

      Thanks for checking in with us about the performance of Tarp Ponchos. We are indeed still tending the blog, although we’ve been beset by gremlins recently which have prevented email questions being forwarded. So – sorry for the delay in posting this response.

      A poncho actually works in quite a different way than a rain jacket when it comes to keeping a hiker dry. A rain jacket fits around your torso and arms, and therefore a backpack will be carried outside of the jacket, with the shoulder straps and hip belt pressing against the fabric of the jacket. For this reason, a rain jacket has to be made of a fabric with a very high hydrostatic head to prevent water being forced through the fabric by the pressure exerted by the pack harness.

      In contrast, a poncho works like a tarp: it sits outside of the backpack which the hiker is carrying and therefore is not subject to pressure from the harness. It is, essentially, a loose-fitting tarp which the user wears, and from which rain should just run off.

      The hydrostatic head of both the regular 70D Nylon Tarp Poncho and the 15D Ultra-Sil Nano Tarp Poncho is adequate to repel rain in these circumstances; the main differences between the two products is the weight and packed volume.

      However, if you find yourself hiking for hours in torrential rain (think Scandinavia / Ireland / West Coast of New Zealand) for hours, you may get to a point where the fabric of either of these Tarp Ponchos eventually becomes overloaded. To be fair, I can’t remember the last time a consumer reported an issue of this kind.

      If you would like more details on this, drop us a line at marketing@seatosummit.com and put ‘Tarp Poncho performance questions’



  2. Hi!

    Does the seam tape of dry storage like Big River Dry Bag have warranty? The seam tape of my dry bag along the folds of the roll top cover has worn out and started to have slits. Can this be replaced or repaired?

    1. G’Day Ruel

      Sorry to learn that your Big River Dry Bag is looking a little worse for wear.

      All Sea to Summit products are warrantied against manufacturing and material defects for the useful life of the product. In this case, if the seam tape has failed, we would regard that as a warranty; if it has simply worn through from use over an extended period, we would regard this as wear and tear.

      Can you please email us at info@seatosummit.com with some high resolution images of the damaged seam tape? Please let us know where and when the dry bag was purchased and your full shipping address. Include ‘Big River Dry Bag seam tape issue’ in the subject line.



      1. I was just hoping to repair my Big River Dry Bag but to my surprise, Sea to Summit coordinated with R.O.X. Philippines to replace my bag with a new one. Wow! The store staff also shared with me product care tips to make the bag last longer. Great product and customer support. Way to go, Sea to Summit!

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