Drybag

A roll-top is a seal, not a lid

A drybag keeps water out with the fold at its mouth rather than with the buckle that holds the fold shut. Roll the top down on itself several times, press the air out as it goes, then clip the ends together and the trapped fold becomes the seal. Understanding that changes how one is used, and it explains why an overfilled bag leaks: there is not enough material left above the contents to roll.

How is a drybag closed properly?

Leave a clear span of empty fabric at the top, flatten the opening so the two edges meet cleanly, then fold it over at least three times in the same direction before clipping. Squeezing most of the air out first makes the roll tighter and the bag easier to pack; leaving a little air in makes it float, which matters on open water and is the reason the wider waterproof bags family exists in so many sizes.

Which material for which use?

Heavy coated tarpaulin resists abrasion from a boat floor, a rock ledge or a trailer, and it stands up on its own when packed, at the cost of weight and bulk. Lightweight coated nylon rolls into almost nothing and suits a rucksack liner or a summer bike bag, but it wears at the corners far sooner if dragged. Welded seams have no needle holes, while a stitched seam depends entirely on the tape sealing it, and the tape is where age shows first.

What size and how many?

• One large liner: a single bag inside the rucksack keeps everything dry and is faster than sorting kit at a wet pitch.
• Small sorted bags: separate colours for clothing, electronics and food make items findable without unpacking the lot in the rain.
• Phone size: a clear pocket keeps a touchscreen usable through the window, though photographs taken through it lose sharpness.
• Colour: orange and bright shades are easy to spot on dark water or under a bench seat, while black hides in the bottom of a boat.
• Carry system: shoulder straps turn a large bag into a pack, and a plain sack has to go inside something else.

What is worth putting in one?

Whatever ruins the trip if it gets wet: spare insulation, a phone, matches, documents and above all a sleeping bag, since down that gets soaked stops insulating and takes days to recover. For paddling, swimming and anything where the whole load may go under, a dedicated waterproof backpack with a rolled closure of its own removes the step of packing bags inside a bag.

How are drybags cleaned and stored?

Rinse salt water off after coastal use, because dried salt is abrasive and grinds at the coating from inside the folds. Dry them inside out and store them open rather than rolled, so the fold line is not held under pressure for months at a time. A pinhole found at home, with the bag inflated and held under water, is a two-minute repair; the same hole found at a river crossing is not.