Most people learn which of their swimsuits dries fast the unglamorous way. One is ready to pull a dress over by the time you reach the car. Another is still cold and heavy at lunch, leaving a damp outline on a café chair and a chill that lasts well into the afternoon. The difference is rarely luck and rarely the weather. It is built into the suit long before it meets the water, in the fibre it is spun from, the way it is knitted and what has been sewn inside it.
Quick-dry is one of the most used phrases on a swimwear label and one of the least explained. It helps to know what is actually happening as a suit dries, because once you do, you can judge it for yourself.
Water sits on a fibre or inside it
A wet swimsuit holds water in two places. Some is absorbed into the fibres themselves, and the rest is trapped in the tiny spaces between yarns and between layers. The first kind is slow to leave, because it has to work its way out of the fibre before it can evaporate. The second kind leaves quickly, provided it has somewhere to go. This is why natural fibres make poor swimwear. Cotton drinks water deep into every fibre and gives it back grudgingly, which is why a cotton towel stays damp for hours. The synthetic fibres used in swim fabric, nylon and polyester, absorb very little. Water clings to their surface rather than soaking in, so most of it can be shaken, wicked or evaporated away. Elastane, the stretch fibre blended in for fit and recovery, behaves in much the same way.
The knit decides how fast it leaves
Fibre is only half of it. The same yarn can dry quickly or slowly depending on how it is knitted. A smooth, dense jersey presents an even surface to the air, and water spreads across it in a thin film that evaporates readily. A fabric with a loose, lofty or textured structure, such as terry, heavy ribbing or crinkled novelty knits, holds pockets of water in its texture and releases them slowly. Good swim knits are also engineered to move moisture along the yarn, spreading it out rather than letting it pool, and more surface in contact with the air means faster drying. There is a trade-off worth being honest about. A heavier, denser fabric carries more material, so it will always hold a little more water than a flimsy one. But thin fabric that dries quickly and goes sheer when wet is not a bargain. The aim is a knit that is substantial enough to hold its shape and opacity yet sheds water efficiently.
What slows a suit down
When a suit stays wet all afternoon, the reason is usually one of a handful of things, and most of them have little to do with the outer fabric.
- 01Foam cups and thick padding, which absorb water like a sponge and are the last part of any suit to dry.
- 02Cotton or cotton-blend gussets and linings, which undo the work of a synthetic shell.
- 03Bulky folded seams and layered trims, where water collects in the channels between layers.
- 04Textured, ribbed or terry surfaces that trap water in their structure.
- 05Residue from sunscreen, salt and chlorine left in the fabric, which can clog the knit and change how water moves through it over time.
A suit dries as fast as its slowest part. The shell can be ready in minutes while a sodden cup keeps the whole thing cold.
Conditions still play their part
Even the best fabric depends on air. Moving air dries a suit far faster than still air, and low humidity faster than a heavy, humid afternoon. A suit worn in a light breeze dries quickly because your own warmth helps drive the water off. The same suit rolled in a towel and pushed into a bag does not dry at all, and it is exposed to the damp heat that is hardest on elastane. Hanging a suit in direct sun is tempting because it feels fastest, but UV breaks down fibres and fades colour over a season, and a shaded, airy spot does nearly as well without the cost.
How RIVA approaches it
RIVA's fabric is chosen with the walk home in mind. The collection is cut from a double-lined sculpting Italian jersey from a family mill on Lake Como, a chlorine and UV-resistant, recycled quick-dry knit that springs back to shape and dries on the walk home, with shells spun from regenerated ocean nylon. Double lining is there so every shape stays opaque when wet, and the seams are bonded rather than bulked up. Every piece is tested wet, stretched and dived in before it earns a place. Care keeps it that way: rinse in cool water after every swim to clear salt, chlorine and sunscreen, hand-wash gently, never wring, and dry flat in the shade. Skip the tumble dryer and the sunny windowsill, and the fabric will keep drying as quickly in its third summer as it did in its first.