Silnylon or urethane coated

[Chethro]

When you touch a wet tarp from the inside will silnylon or the urethane coated nylon taffeta pass the moisture?

I'm trying to decide if I should go with the more expensive McCat or Warbonnet Big mambajamba or a cheaper urethane coated rectangular type. I probably won't be camping in the winter.

[Just Jeff]

Sil can pass moisture if it has pressure on it...that usually doesn't happen under normal use, but if you have something pressing on the tarp it can soak thru. Very heavy rains can sometimes mist thru but it's not really a problem...that's why most people use it.

Urethane coated is heavier so it's less susceptible to this. It can also delaminate over time, which sil doesn't do.

[Cannibal]

Oh yeah, sil will pass thru moisture; extremely irritating when it's cold and wet out and you've got nice warm, dry clothes on as you climb into your hammock.

Go with the 'more expensive' options if you are even kind of concerned with long life and weight. Just be aware that you will, at some point, be mad at any tarp you buy; nature of the beast. If you feel like spending a little more coin, Brian (OES-MacCat) will make you a tarp of Spinntex. Oh man is this stuff sweet! You won't have to worry about moisture pass-thru, crazy lightweight, and so far, very durable.