80% of boat sinkings happen at the dock — not underway.

Know the moment your bilge starts rising — wherever you are.

A text the moment water rises. No app required.

A depth probe in your bilge sends an SMS the moment water crosses a threshold you set. The firmware is open source — build your own for ~$200 in parts, or order a fully assembled, managed kit.

Get early access → See your options

Depth ±1^cm

Range up to 100^cm

Notify SMS^{2 tiers}

Built by a programmer and a marina tech — field-testing now

FIG. 00 / HERO "Bilge-to-phone" [ foreground: hand holding phone, SMS alert on screen
background: dark bilge water visible · shallow depth of field ]

Two ways to run it

Your boat, your choice.

The core is open source and always will be. Run it yourself on hardware you source, or let us handle the build and the infrastructure.

Open source

Roll your own.

The firmware and schematics live on GitHub under MIT license. Source parts from our BOM — around $200 in components — flash an ESP32, and you're monitoring. No subscription, no cloud dependency.

Firmware on GitHub — MIT licensed
Wiring diagram + hardware BOM
Parts BOM, ~$200 in components
Self-host or bring your own SMS provider
Community forum & issue tracker

I'd build it myself →

Free forever · no account needed

Ready to run

Plug in and go.

A weatherproofed, pre-flashed unit with LTE-M cellular and a SIM already inside. Mount the probe, connect 12 V, done. We run the alert platform so you never have to think about servers or SMS credits.

Pre-assembled & tested
LTE-M cellular + SIM included
Managed alert platform — SMS + Discord alerts
OTA firmware updates, automatically
1-year hardware warranty + email support

I want the kit →

Device + first year of alerts included

Both paths run identical firmware. DIY builders can switch to the managed platform at any time — your config migrates automatically.

2 minutes · help us build it right

Tell us about your boat.

Whether you're planning to build from source or buy the assembled kit, your answers help us prioritize — hardware, docs, and the managed platform.

Your email at the end so we can follow up when the kit is ready to ship. No newsletter, ever.

Q1 Length of your boat?

Q2 How do you monitor your bilge today?

Q3 What would you expect to pay — device included, no contract?

An annual plan for SMS notifications would be on top of the device price.

Q4 Which path interests you most?

Helps us know how much to invest in docs, community tools, and the managed platform.

Q5 Your email * required

One update when v1 is ready to ship. If you opt in below, a couple of follow-up questions as the prototype evolves.

OK to follow up with a question or two as the prototype evolves.

* email is the only required field · the rest helps us prioritize

FIG. 01 / SENSOR The probe, in the bilge. [ large · close-up · probe mounted vertically, tip in water · cable visible ]

Fig. 01 — the probe

Direct-contact depth sensing.

A probe mounted in the bilge reads water depth to the centimetre. Runs off 12 V boat power, sits low, doesn't care about diesel sheen.

FIG. 02 / NOTIFICATION The text, on your phone. [ large · phone in hand · SMS thread visible · "Water at 22 cm — above your warning threshold" ]

Fig. 02 — the alert

One text at warning, another at emergency.

You set both thresholds. The device texts you wherever cellular reaches you — no app to keep logged into.

Operating principle

Two thresholds. A text when either is crossed.

FIG. 03 · BILGE CROSS-SECTION scale ≈ 1:5 · soundings in cm

Tier 01 · Warning

"Water is rising — heads up."

SMS to your number when water crosses your first threshold. Probably nothing. Worth a glance from wherever you are.

Tier 02 · Emergency

"This needs your attention now."

At the higher threshold, alerts escalate to emergency priority. A screw-terminal output (planned) lets you wire in your own horn or relay. It clears automatically when the water drops.

Under the hood · prototype v0.4

What the prototype
does right now.

Honest numbers from the v0.4 prototype we're testing this season. Some of these will firm up as we move toward production — what's planned is noted in line.

Sensing	Depth probe · direct water contact
Range / acc.	up to 100 cm, ±1 cm typical
Sample rate	~1 s continuous
Connectivity	WiFi LTE-M cellular planned (adds SIM cost)
Power	12 V boat power Battery backup planned
Mounting	3M VHB or screw bracket · bilge floor or wall
Enclosure	Off-the-shelf project box Not yet rated · production enclosure TBD
Alerts	Tier 01 — SMS + Discord · Tier 02 — emergency escalation + horn/relay terminal Planned
Config	Browser-based · no app install