Waterproof Bags

Waterproof bags, judged by the closure rather than the label

Waterproof bags cover two separate jobs: stopping rain from reaching the contents, and staying usable once the outside is soaked. The range runs from small roll-top sacks meant to live inside a larger pack, through duffels around 55 litres, up to rucksacks of 90 litres. Fabric gets the attention, but the closure is what decides how much water actually gets in.

What is the difference between waterproof and water resistant?

A water resistant bag has a coated face fabric and will shrug off a shower. A genuinely waterproof one also deals with the two places water sneaks through: the seams, where a sewing needle has left a line of holes, and the opening. Welded or taped seams close the first. A roll-top closes the second by folding the fabric over itself several times before the buckle clips, which is why a drybag with no zip at all is the simplest thing to trust in a canoe or on a wet crossing.

Which capacity suits which kind of trip?

Litres describe volume when the bag is packed, not when it is rolled shut, so a roll-top loses some of its stated capacity every time it is sealed properly. Around 40 litres carries a day out with layers, food and a flask. Fifty litres starts to take an overnight kit. Eighty to ninety litres is kit-bag territory: a full change of clothing, boots and bulky insulation, usually carried short distances rather than walked in all day. Larger is not automatically better, since a half-empty bag sags and rubs.

What should be checked before buying one?

• Closure: roll-top for immersion and heavy rain, coated zip for quick access, plain zip only for showers.
• Seams: look for welded or taped joins on the panels; visible stitching on an outer seam is a route for water.
• Carry system: shoulder straps and a hip belt for anything walked with, grab handles for a duffel that gets thrown into a boot.
• Base fabric: the underside takes the abrasion, so a heavier panel there outlasts one made of the same cloth as the sides.
• Openings: every external pocket, drain hole and lash point is another interruption in the waterproof shell.

For walking, a waterproof backpack keeps the load against the back rather than swinging off one shoulder. Holdalls and pouches where dryness matters less than volume sit in the wider military bags selection.

Where do waterproof bags fail first?

At the fold of a roll-top, where the same crease is stressed each time, and at the strap anchor points, where stitching passes straight through the shell. Grit trapped under the base wears the coating from the outside in. Loading a bag until it is drum tight puts pressure on those same anchors, which is the fastest way to open a small leak.

How should a waterproof bag be cleaned and stored?

Rinse mud and salt off with plain water, sponge the inside, then hang it open until it is dry right through. Detergents and machine washing strip coatings. Store it loosely rolled or hung rather than crushed flat under other kit, because a permanent hard crease in a coated fabric eventually cracks along the line.