When we set out to build the Swimmer's Notes workout builder, we had one non-negotiable constraint: it had to work flawlessly with wet hands.
This single requirement changed everything about our design process.
The Problem with Standard Mobile UX
Most mobile apps are designed for dry fingers on a comfortable couch. Small buttons, precise scrolling, text input fields — these all assume ideal conditions. At the pool deck, you have:
- Wet fingers that slip on glass screens
- A phone that might be in a waterproof case (adding thickness)
- About 10 seconds between sets to log data
- Distractions everywhere (coach yelling, teammates splashing)
Our Design Principles
1. Minimum 48px touch targets. Apple recommends 44pt as a minimum. We went bigger — every interactive element is at least 48px, and primary actions like stroke chips are 56px+.
2. Tap, don't type. We replaced text input with a custom number pad for distances. Instead of typing "100," you tap 1-0-0 on large buttons. For strokes, it's a single tap on a chip. No keyboard, no autocorrect, no fumbling.
3. Chunked interactions. Each set follows the same pattern: distance → stroke → add. Three taps. We tested this workflow with actual swimmers at practice and iterated until the average set-logging time was under 5 seconds.
4. Visual confirmation. Every action provides immediate, unmistakable feedback. Adding a set plays a subtle animation and updates the set list. No wondering if your tap registered.
Testing at the Pool
We tested prototypes with a garden hose. Literally. We'd spray our hands, then try to log sets as fast as possible. Any interaction that failed the "wet hose test" got redesigned.
The result is a builder that feels natural at practice — fast enough that you can log between sets without holding up the lane, reliable enough that you never lose a workout.