Here are some of my ramblings on Goretex:
When Goretex bivi bags first came out, it was thought that they were the answer to sleeping in the wet. If only it was so simple.
Goretex bivi bags are good but for them to work there are certain ground rules. The body produces copious quantities of moisture during a good sleep. For the goretex to let this out the outer surface must not be saturated with water and plenty of air must circulate around it. In translating, this amounts to not setting up your bivi bag in a puddle/ground water and protecting it from direct rain with a basha/tarpaulin.
I love my issue Taslan Goretex raingear. For standing still in torential rain it works for me, but that's because its a relatively new one. I stitched up a friend of mine by giving him one of my old sets(8 yrs old). It failed completely the other day in Scotland and he was drenched.
When soldiering, being very active, you work damp. Warm and damp is no real hardship, but the danger arises when you stop work. Cold and damp can be leathal. This is were the layered system works best. However, for the layered system to work it takes discipline. It is a learned/experience skill to "bother" changing clothing with the highs and lows of your work load. Climatisation is another completely underestimated factor, but thats another story.
Turning water into water vapour uses huge amounts of energy, more than your body can afford to use. Wind action removes water and vapour much faster but also takes away any heat.
Unless cold and dry, goretex doesn't work fast enough, so water accumulates on the inside of the suit. One way to rid yourself of some of this excess water/dampness is to give your undergarments a good airing under cover. Modern fibrepiles (best with a pertex outer for windproofing) not only retain heat when damp but are also efficient at wicking away moisture where the wind can take it away. So take off your goretex under a basha and let your fibrepile have the chance to work. Twenty minutes is all that it takes and then you can put your goretex back on. You may still be a little warm damp, but you won't be wet damp. Don't forget to give the inside of your gortex an airing too. If you can stay out of the rain then the goretex will start to work again removing even more moisture. You might even become dry within an hour or so. This works with boots as well. It takes three pairs of thick dry socks to dry a goretex boot.
Its all part of personal administration in the field; which is hard work but has to be done if you intend surviving/working in the elements for a sustained period of time. Its easy to pick out the more experienced soldiers because they do this job fast and have their kit well organised for the task.
For most of us, who can return to a heated cabin, Goretex is a good enough outer waterproof and windproof shell. It is far superiour to the total barrier waterproof. Unfortunately, it is not the complete solution the advertisments would like us to believe. Further performance has to come from your other clothing layers. Goretex is fragile, so you can prolong its life by only wearing it when you have to or expect to replace it every year or so.
If its not raining hard then a windproof that is rain resistant is probably better/more breathable.
