Improves waterproofing!

Part of the rational behind using a ShellTA as well as a conventional waterproof is because all waterproofs degrade.

The most obvious reduction in performance comes because the water repellency of the outer fabric is lost, because of dirt, abrasion, water pressure or contamination with water softeners. This causes the fabrics to become saturated and the inside is likely to reach the dew point, causing condensation and a loss of breathability.

Conventional membrane waterproofs may also be punctured, membranes can crack, abrade and delaminate and seam tape can peel off.

Some of these problems only manifest themselves in extremely wet weather and the ShellTA gives you another tool to reinforce your waterproofs in those rare extremely wet conditions. It provides a “defence in depth”.

Improving venting with the ShellTA

When the inside of your ShellTA becomes wet (normal when layered over wet softshells in the rain) it tends to stick to inner layers that are already water logged. This reduces venting, insulation and wet weather breathability. However, when you wear the ShellTA over your sack, like a poncho, this seperates the fabrics and improves performance.

When you wear the ShellTA under your sack, ease the front fabric out from beneath your hip belt and shoulder straps to separate it from under layers.

What happens when the ShellTA fabric becomes saturated?

Like any waterproof breathable fabric, breathability stops when the fabric becomes saturated, however it remains waterproof. Wind will help breathability, even in the rain, especially if air is allowed to circulate through the ShellTA.

The fabric of my sleeve was wet before getting in the ShellTA

When you wear it over a wet waterproof the water tends to stick to the ShellTA, providing a useful drying effect. Once it is saturated this effect diminishes and air circulation beneath the waterproof canopy is the only way drying will continue.

Why use a lunch ShellTA when it’s not raining?

Although the ShellTA is made from a thin waterproof fabric, with little inherent insulation, two people sat together inside can share a surprising amount of heat that would otherwise be lost to the atmosphere. It’s also a very simple way of adding extra protection for your legs, without the hassle of overtrousers …and it doesn’t need to spoil the view: each person can open their side vent to peer out and breathe in the mountain vista.