Stump Sound Tide Clock

mid‑sound · Permuda Island

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Right now at your dock

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— ft

Next high

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Next low

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Tide height

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above local low water

Today's range

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Your trip

Calculating…

The fine print

Trip planner

Pick a departure and how long you plan to be out. It checks the water at your dock at both ends of the trip.

Cast off

Time out min

Departure windows

Every stretch ahead with enough water to leave the dock and get back in.

Depth at your dock

Modelled from NOAA — predictions, shifted and scaled to your spot.

Expected depth Could plausibly sit here Below your minimum Now Night

Seven‑day outlook

Tide events at your spot, and how much of each day clears your minimum depth.

Day	Tides at your dock	Navigable	Deepest

Predictions from NOAA CO‑OPS station 8657419, transformed to your location in Stump Sound using a user‑calibrated time lag and range scale. NOAA operates no tide station inside Stump Sound — everything here is a model. When you have signal it also folds in forecast wind (Open‑Meteo) and the measured ocean surge at Wrightsville Beach, shown as a band; these are estimates and the wind knob is yours to calibrate. Wind, rain, river discharge and surge routinely move real water level by half a foot or more in a back sound, and the band cannot promise to catch all of it. Never use this as your only source for navigation. Carry a chart and a working depth sounder.

Works with no signal: a full harmonic tide engine (37 NOAA constituents with Schureman nodal corrections) is built into this page, so it keeps predicting on the water. Checked against NOAA's own published predictions over 44 tide events at three stations — agreeing to about 2 minutes and 0.05 ft. When you have a connection it quietly swaps in NOAA's official numbers and caches 400 days of them.

Data: NOAA Tides & Currents. Times shown in your device's local time zone ().

Calibrate

Tune the model to what you actually see off your dock. Everything saves to this device and to the page address — bookmark the page after you change things and your settings travel with the link.

Your dock

Depth you sound at your dock on an ordinary low and an ordinary high tide. These two numbers set the whole scale.

Depth at mean low wateryour shallowest normal reading

Depth at mean high wateryour deepest normal reading

Your boat

At your dock the binding number is almost never the hull — it's whatever you leave hanging in the water. Pick how you'll come in and the app uses the right one.

Hull draft9 in — everything tilted up

Trolling motor prop depthhow deep you usually set the shaft

Outboard skeg depthwaterline to skeg, motor down

Draft on planehull up on top, motor trimmed out

Hole shot draftdeepest moment — stern squats before she rises

Safety clearancewater you want under the keel

Your run

The sound entry is the landmark everything hangs off. From there it's a fixed no-wake run to your dock, and that whole leg has to have water in it — not just the minute you tie up.

No-wake legminutes, sound entry ↔ your dock

Run in from where you fishminutes back to the sound entry — optional

Wind & surge

The tide model is astronomical — it doesn't know the weather. When you have signal the app folds in forecast wind and the measured ocean surge at Wrightsville Beach, and draws the water as a band instead of one hopeful line. In a back sound these routinely move the water half a foot — more than your margin — so the trip calls are made off the band's lower edge.

Fold weather into the water level

Wind sensitivityinches the water moves in a 15 kt wind straight down the sound — tune this from what you see

Which wind raises your waterthe direction it blows FROM. Flip it if the app reads backwards for your spot.

Use the live ocean surge (Wrightsville Bch, 25 mi)

Because your water lags the ocean ~4½ hr, the surge measured now is a preview of what's coming to your dock — damped by the same choking that flattens your tide.

Local timing

How far the tide at your dock lags the NOAA station. Yours runs about 4 hr 35 min behind the ocean — measured off your wall clock, not assumed. That is far more than wave travel time over the 13 miles from either inlet; most of it is the sound filling and draining through narrow throats, which lags the ocean and flattens the swing at the same time.

NOAA source station

High‑tide lagminutes after the station

Low‑tide lagminutes after the station

Teach it

Two taps that make this thing yours. Do each once and the model stops guessing.

My sounder reads right nowsets the depth offset

Cross-check your wall clock

Your ceramic clock is the thing that calibrated this app. Two readings 22½ hours apart both solved to the same 4 hr 35 min lag behind the ocean — agreeing within 4 minutes. If the hand below stops matching your wall clock, one of you has drifted.

Your wall clock should pointhigh tide at 12, low tide at 6 —

A mechanical tide clock runs a fixed 12 h 25 m cycle, so it still can't show the unequal highs or the fact that the real interval here wanders by ±15 min a cycle. Expect it to wander from this app by up to half an hour and to need a nudge every few months. The dial on the main screen is driven by the actual predicted turn times, so it doesn't drift.

Version 1.3 · Offline harmonic model, cached NOAA data, forecast wind & measured ocean surge with signal, an interactive trip planner, and a day/night theme.