Why I Built Gillby

What did checking the water used to look like?

I'm not from Florida, but I've been down here for years. Boating is newer for me. I run a 2008 Contender 21 Open out of the Deerfield, Boca and Pompano stretch, and I'm still learning this water.

When you're new, you don't have years of instinct to lean on. So before every trip I ran the same routine.

A wind app. A wave app. A tide app. A radar app. Then a couple of sites to guess what the inlet and the sandbar would look like when I got there.

Every one ran on its own clock. Every one had its own idea of where I was. I would stitch it together in my head, head out, and still get caught in the rain.

My wife said it out loud before I did. It was way too hard to get a good read on the weather without checking five different things. And when we asked an AI, it did not have good answers on its own. That is part of why Gillby also plugs into AI assistants like Claude and ChatGPT, so they can answer from real water data.

So I built the thing we wanted.

One map. One clock.

Gillby puts the whole picture on one map and one timeline. Slide to the hour you want to leave and everything moves with you: wind, waves, tide, radar and lightning.

Pick what you are doing today and you get one verdict for it. Pick your boat and the chop reading changes, because a 21-footer and a 35-footer do not ride the same sea.

Less scrolling. More salt water.

What does Gillby do today?

• Seven days of hourly conditions for each spot, built from the big wave and weather models, NWS forecasts, NOAA tides and the buoys.
• A local correction trained on about ten months of nearby buoy data. On held-out data it cut wave-height error from 0.45 to 0.36 ft and wind error from 1.9 to 1.5 kt.
• Go or no-go for each inlet, plus a chop index tuned to your boat.
• Lightning from the GOES-19 satellite every 20 seconds, with an all-clear countdown.
• Radar, satellite, NOAA charts and depth shading on the same map.
• Route checks that know your draft, the tide, the bridges and your departure window.
• 1,181 sandbars with how much water is over the bar right now.
• Marinas, ramps, fuel docks, wrecks, reefs and anchorages. About 3,600 places.
• Beach cams, right inside the app.
• Float plans you can share with the people who should know where you went.
• Ask Gillby in plain English, in the app or from Claude and ChatGPT.

It started with my home water. It now covers spots across Florida, from the Keys to the Panhandle.

What Gillby is not

Gillby is not a navigation chart. Use it to plan, then trust your eyes, your sounder and the official advisories.

Why a passion project?

Gillby is a hobby. I built it because I needed it, and I check it every time I go out.

If it saves you from juggling five apps on the dock, it did its job. If something is missing for your water, tell me. That is how it gets better.

Start with how I read Boca Inlet before I run it, or open the water map.