Slackwater VS Datify

Slackwater's answer

The tide math runs on the phone. Slackwater carries the NOAA harmonic constituents for the stations you save and computes the curve locally, so the tide times, the solunar windows and the alerts all still work in a marsh or a canyon with no bars. Several of the free tide apps are online only, which fails in exactly the places you need them. Slack water also gets treated as a first-class thing here: the app tells you when the current actually turns, not only when the height peaks, which is the moment most of this planning is really about.

Slackwater's answer

Scope and price for the person actually standing in the water. The large fishing platform runs about $75 a year and is mostly a social network with a catch log around it. Slackwater is a timing tool: $24.99 a year, $3.99 a month, or $39.99 once for Lifetime, and free for three spots with no ads and no account. It also covers the parts the simpler free tide apps leave out, including slack water and the current turn, a bite rating for the day, alerts at any tide height you choose, a session log that fills in the conditions for you, and an Apple Watch app with widgets and a Live Activity so the next tide is on your wrist and your lock screen.

Slackwater's answer

Inshore and surf anglers, kayak and small boat people, surfers, clammers, and anyone whose plan for the next six hours depends on what the water is doing. They tend to fish the same handful of places over and over, which is why the free tier is three spots rather than a countdown to a paywall. Most of them are standing somewhere with one bar or none, so working offline is a requirement here rather than a bonus feature.